Sweet Corn Newsletter No. 5 – July 24, 2015

July 24th, 2015 1:54 PM

Sweet CornSweet Corn IPM Newsletter No. 5 – July 24, 2015
Click on photos to enlarge.

HIGH FALL ARMYWORM COUNTS CONTINUE

Corn Earworm Numbers Lower this Week

SITUATION
Corn harvest is underway in southern Maine. Growth continues to be erratic, with cool night temperatures and dry conditions in much of the state. It looks as though early season supply will be spotty in many areas. Insect pressure is primarily coming from fall armyworm, as both European corn borer and corn earworm numbers have dropped off in most fields this week.

European corn borer: Moth catches dropped to very low levels this week, with most sites catching no moths and no sites exceeding the silking corn threshold of 5 moths. European corn borer feeding damage has also dropped off with only one field in Cape Elizabeth over the 15% damage threshold in a pre-tassel field. There is a chance that a second generation of European corn borer moths could emerge late in the summer to threaten late silking corn, especially in far southern Maine.

Corn earworm: Trap captures of moths were generally very low this week, perhaps due to cool night temperatures with showers and fog in many locations. A 6-day spray interval was recommended for silking cornfields in Garland, Farmington, Oxford and Wells. A 5-day spray interval was recommended for a silking field in Auburn. A 4-day spray interval was recommended for one field in Cape Elizabeth. It is likely that moth counts will rise again when warmer night temperatures return, or more storm fronts arrive from the south.

Fall Armyworm Moths

Fall Armyworm Moths (female right, male left), photo by James Dill

Fall Armyworm Eggs on Corn

Fall Armyworm Eggs on Corn, photo by David Handley

Fall armyworm: Moth counts continue to climb at our trap locations this week. Sprays to protect silking corn from egg-laying moths were recommended at most sites. Silking fields in Auburn, Biddeford, Bowdoinham, Cape Elizabeth, Dayton, Garland, Farmington, Lewiston, New Gloucester, Nobleboro, North Berwick, Oxford, Poland Spring, Wales, Warren, Wayne and Wells were over the control threshold of three moths caught in pheromone traps. The fields in Auburn, Cape Elizabeth, Farmington, Garland, Oxford and Wells were also on spray schedules for corn earworm, so no additional sprays for fall armyworm were recommended at those sites.

Squash vine borer: Moth counts indicate that the threat level to pumpkins and squash continues to be high in most locations this week. The threshold of five moths per week in pheromone traps was exceeded in Biddeford, Cape Elizabeth, and Wells.

Potato Leafhopper

Potato Leafhopper, photo by James Dill

Potato leafhopper alert: We are seeing signs of potato leafhopper in vegetable and strawberry fields this week. These small, bullet-shaped insects feed on plant sap from the undersides of leaves, causing the leaves to become curled, stunted and yellow-streaked. Beans are often the first crop to show symptoms, but other crops are also susceptible, including potatoes and strawberries. To scout for leafhoppers, brush the leaves of the plants with your hand. The small, whitish adults can be seen flying off the plant. Look for small, light green leafhopper nymphs on the underside of injured leaves. They are about 1/16 inch long. When touched, they will crawl sideways in a crab-like manner. Control options for potato leafhoppers are listed in the New England Vegetable Management Guide and the New England Small Fruit Management Guide.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                             491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                           1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 6 0 10 0% 5-day spray interval recommended on all silking corn
Biddeford 0 0 10 10% One spray recommended for FAW on silking corn
Bowdoinham 0 0 3 2% One spray recommended for FAW on silking corn
Cape Elizabeth I 0 1 25 One spray recommended for FAW on silking corn
Cape Elizabeth II 17 0 108 21% 4-day spray interval recommended on all silking corn
Charleston 2 0 0 0% No spray recommended (no silking corn)
Dayton 0 0 23 0% One spray recommended for FAW on silking corn
Farmington 2 0 5 0% 6-day spray interval recommended on all silking corn
Garland 2 0 5 0% 6-day spray interval recommended on all silking corn
Levant 1 0 1 3% No spray recommended
Lewiston 0 0 8 2% One spray recommended for FAW on silking corn
New Gloucester 0 0 69 0% One spray recommended for FAW on silking corn
Nobleboro 0 0 5 One spray recommended for FAW on silking corn
No. Berwick 1 0 10 0% One spray recommended for FAW on silking corn
Oxford 2 0 6 0% 6-day spray interval recommended on all silking corn
Palmyra 0 2 0 3% No spray recommended
Poland Spring 1 0 5 One spray recommended for FAW on silking corn
Wales 1 0 3 0% One spray recommended for FAW on silking corn
Warren 1 0 3 One spray recommended for FAW on silking corn
Wayne 1 0 5 6% One spray recommended for FAW on silking corn
Wells I 1 0 15 0% One spray recommended for FAW on silking corn
Wells II 2 0 9 3% 6-day spray interval recommended on all silking corn

CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

Spotted Wing Drosophila Alert: July 20, 2015

July 21st, 2015 2:59 PM
Male and Female Spotted Wing Drosophila Flies

Male (left) and Female (right) Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

SPOTTED WING DROSOPHILA ALERT: JULY 20, 2015

Click on photos to enlarge.

David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist; Frank Drummond, Professor of Insect Ecology/Entomology

Spotted wing drosophila (Drosophila suzukii) is a new pest that is a concern for growers of raspberries, blueberries and day-neutral strawberries. This small fruit fly is similar to those that hover around the ripe bananas in your kitchen, but this species will lay its eggs on fruit before it ripens, resulting in fruit that is contaminated with small white maggots just as it is ready to pick. Infested fruit quickly rots and has no shelf life. Spotted wing drosophila can complete a generation in under two weeks, with each adult female laying hundreds of eggs. Therefore, millions of flies can be present soon after the introduction of just a few into a field. Repeated insecticide sprays (1 to 2 per week) may be needed to prevent infestations once the insect is present in a field. The flies can successfully overwinter in Maine, although they may not build up to damaging levels until late summer. We have set out monitoring traps for spotted winged drosophila around the state to determine its activity in berry fields. However, these traps may not provide adequate early warning, i.e. when we find them in a trap they are probably already getting established in the field.

We have found a few spotted wing drosophila in Maine over the past week, including single flies in Buxton and Limington and two flies in a trap in Mechanic Falls. These are not yet damaging numbers. Research in Maine and other regions suggests that when 6 to 10 flies are caught in a yeast-baited trap in a week, larvae will start appearing in the fruit.

Products that provide good control of drosophila on berry crops include spinosad (Radiant® for strawberries, Delegate® for raspberries and blueberries), Brigade®, Danitol®, malathion and Assail®. Research suggests that adding table sugar to group 4A insecticides, such as Assail®, may improve their effectiveness. The recommended rate would be 1-2 lbs. sugar per 100 gallons of spray. Please check product labels for rates, post-harvest intervals and safety precautions. Keeping fields clean of overripe and rotten fruit will also help reduce the incidence of this insect.

For more information on identifying spotted wing drosophila (SWD) and updates on populations around the state, visit our SWD blog. Other SWD sites include:

drosophila trap

Drosophila Trap, photo by David Handley

Michigan State University’s website,
Pennsylvania State University’s SWD website, and
University of New Hampshire’s SWD web page.

Spotted wing drosophila populations may start to build rapidly in the coming weeks as more food (fruit) becomes available for the flies, especially if conditions remain warm and humid. Now is the time to set out traps, if you haven’t already. Start protective sprays on any berries that have begun to ripen, once more than 4 spotted wing drosophila flies are caught in a trap, or any larvae are noticed in the fruit. Look for fruit flies hovering around fruit and symptoms of premature fruit decay.

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                             491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                           1.800.287.0279

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

The University of Maine is an equal opportunity/affirmative action institution.

Sweet Corn Newsletter No. 4 – July 17, 2015

July 20th, 2015 2:11 PM

Sweet CornSweet Corn IPM Newsletter No. 4 – July 17, 2015
Click on photos to enlarge.

FALL ARMYWORM THREATENS SILKING CORN

Corn Earworm Numbers Remain Moderate

SITUATION
Most fields in southern and mid-coast Maine now have silking corn, and harvest is not far away. Many areas could use some rain to help fill out developing ears. While corn earworm and European corn borer pressure remains moderate, fall armyworm numbers increased significantly at nearly all sites and is now a threat to corn at all growth stages.

European corn borer: Moth catches continue to be generally light and scattered around the state, with no sites exceeding the silking corn threshold of 5 moths. European corn borer feeding damage was over threshold in pre-tassel to tasseling fields in Biddeford and North Berwick this week. Remember that larvae are usually most exposed during the pre-tassel stage, so sprays are most effective at that time.

Corn earworm: Trap captures of moths were only slightly higher at a few sites this week, while others had fewer moths than last week. A 6-day spray interval was recommended for silking cornfields in Auburn, Levant, Poland Spring and Warren. A 5-day spray interval was recommended for silking fields in Cape Elizabeth, Garland and Wales.

Fall armyworm: Moths were significantly higher in number and more widely distributed this week. These moths are now laying eggs in young cornfields, and we expect to find feeding damage soon. Silking fields, especially those that are not presently under a spray schedule for corn earworm are seriously threatened by fall armyworm. Moths may lay eggs on the flag leaves of developing ears, and the small larvae can then enter the ears through the silk channel without leaving visible damage to the plant that would be picked up by field scouting. Therefore, when more than 3 fall armyworm moths are caught in pheromone traps in a week, a spray is recommended for all silking corn in a field, unless the field is already under a spray schedule for corn earworm. This week, fields in Auburn, Biddeford, Cape Elizabeth, Garland, Lewiston, Nobleboro and Sabattus were over the threshold for silking corn. Biddeford, Lewiston, Nobleboro and Sabattus were not on spray schedules for corn earworm so sprays on silking fields were recommended at those sites.

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

Two Squash Vine Borer Moths

Two Squash Vine Borer Moths, photo by Jeffrey Hahn, Univ. of Minnesota Extension

Squash vine borer: The threshold of five squash vine borer moths per week in pheromone traps was exceeded in Cape Elizabeth, Dayton and Wells. Sprays for this pest should be directed at the base of the plant to prevent the larvae from boring into the base of squash and pumpkin plants. See the 2014-2015 New England Vegetable Management Guide for details.

Late Blight on Tomato Leaf

Late Blight on Tomato Leaf, photo by James Dill

Late Blight Alert: Infections have been confirmed for potatoes in Vermont and New York. Growers should be scouting potatoes and tomatoes regularly for late blight lesions on the foliage. So far, the drier weather we’ve been having in Maine has not made conditions ideal for this disease. However, with just a few days of warm, wet weather, it could become a serous problem. Applying preventative fungicides can greatly reduce the likelihood of infection. For more information visit our website for Bulletin #2427, Tomato and Potato Late Blight Information for the Upcoming Growing Season, and the New England Vegetable Management Guide.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                             491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                           1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 2 0 11 1% 6-day spray interval recommended on all silking corn
Biddeford 0 1 10 26% One spray recommended for FAW on silking corn
Bowdoinham 0 1 1 0% No spray recommended
Cape Elizabeth 4 1 10 12% 5-day spray interval recommended on all silking corn
Charleston 2 2 0 0% No spray recommended (no silking corn)
Dayton I 1 0 0 1% No spray recommended
Dayton II 1 1 0 8% No spray recommended
Farmington 0 1 2 1% No spray recommended
Garland 5 0 3 1% 5-day spray interval recommended on all silking corn
Levant 2 0 0 0% 6-day spray interval recommended on all silking corn
Lewiston 1 0 7 0% One spray recommended for FAW on silking corn
Nobleboro 0 4 8 7% One spray recommended for FAW on silking corn
No. Berwick 2 0 2 17% 6-day spray interval recommended on all silking corn
Oxford 0 0 1 5% No spray recommended
Palmyra 0 2 0 0% No spray recommended
Poland Spring 2 0 0 10% 6-day spray interval recommended on all silking corn
Sabattus 0 2 10 1% One spray recommended for FAW on silking corn
Wales 4 0 1 2% 5-day spray interval recommended on all silking corn
Warren 2 0 1 13 6-day spray interval recommended on all silking corn
Wayne 1 2 2 6% No spray recommended
Wells I 0 1 1 13% No spray recommended
Wells II 0 0 1 3% No spray recommended

CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

Strawberry IPM Newsletter No. 7 – July 10, 2015

July 13th, 2015 12:03 PM

StrawberriesStrawberry IPM Newsletter No 7 – July 10, 2015

RENOVATION AND WEED MANAGEMENT ISSUE

Time to Get Your Strawberry Beds Ready for Next Year

Be Ready to Manage Pests in Day-Neutral Strawberries

A very cold, long winter resulted in some moderate winter damage to strawberries in some fields, but more than adequate snow cover prevented more serious injury. Good spring growing conditions with little to no frost issues resulted in a pretty good crop in most fields. Fruit size was a bit off in some fields, likely due to very dry conditions in April/May. Weather conditions for harvest were also pretty good and customers were out in force early, although some growers with late fruit had difficulty in keeping the pickers coming after early July. Pest pressure in most fields was light throughout the season. Insects, including tarnished plant bug and strawberry bud weevil or clipper appeared fairly late and often in low numbers. Spider mites were hardly an issue, and cyclamen mites were also low this spring. Root weevils and white grubs were an issue in some fields, especially where problems had been observed last year. Applications of soil insecticides and/or parasitic nematodes seem to have reduced the problem in most situations. Disease pressure was also light in most fields. Dry weather and timely fungicide sprays kept gray mold to a minimum, and foliar diseases, such as powdery mildew and leaf spot only began to show up towards the end of the season.

Don’t forget about your strawberries after harvest. Follow the recommended renovation steps listed below for matted row strawberries as soon after harvest as possible; and continue to scout for and manage disease, insect and weed problems as they arise. Some of the more common issues to be alert for during the summer are listed below.

DISEASES
Foliar diseases should be monitored in your fields by regularly examining leaves. All of the common leaf diseases were present in fields this spring and we should expect that they would continue to be a problem through the summer. The most common summer diseases are powdery mildew, leaf spot and leaf scorch. Fungicides available for these diseases include captan, Topsin-M®, Cabrio®, and Pristine®. See the New England Small Fruit Management Guide for detailed descriptions of these diseases and their management.

Powdery Mildew

Powdery Mildew, photo by David Handley

Leaf Scorch

Leaf Scorch, photo by David Handley

Black root rot is a disease complex which can be brought on by a combination of problems, including nematodes, soil fungi (Rhizoctonia, Pythium), herbicide carryover, and soil compaction. Plants become weak and may wilt and die. Roots on affected plants are black and poorly developed. This tends to be a problem in fields that have been in strawberries constantly for many seasons, and in fields that are under stress in other ways, such as winter injury. Rotating fields to crops other than strawberries for at least three years is an important management strategy for black root rot. Improving soil drainage and breaking up hardpans in the soil may also help. Pre-plant root dips with azoxystrobin (Abound®) may also reduce incidence of black root rot in some fields.

INSECTS
If black vine weevils or strawberry root weevils are a problem in a strawberry field that you would like to carry over, bifenthrin (Brigade®, Bifenture®) can be applied when adult feeding is noticed (usually until mid-late July). Look for notching along the leaf edges and the presence of the black or brown snout beetles. Applications should be made at night when these insects are active, and the highest rate of the insecticide should be used. For control of the grubs a soil drench of Platinum® (thiamethoxam) insecticide should be applied during the fall and/or early spring when the grubs are active in the soil. This product has a 50 day pre-harvest interval and may also be used as a pre-plant or planting treatment for root weevils. Parasitic nematodes such as Heterorhabditis bacteriophora or Steinernema feltiae can also be applied to provide control of root weevil grubs in late August. Nematodes require specialized handling and application. Contact us or talk with one of the suppliers for more details. See the New England Small Fruit Management Guide for sources.

Black Vine Weevil

Black Vine Weevil, photo by David Handley

Strawberry Root Weevil Grub

Strawberry Root Weevil Grub, photo by David Handley

White grubs have been a problem in many fields in recent years. The grubs may be the larvae of several species of scarab beetles, including June beetles, rose chafers, Japanese beetles, Asiatic garden beetles and European chafers. The beetles lay their eggs in June and July and the grubs feed on the roots of strawberries from July through mid-September. Affected plants will be stunted and wilted and may die during dry periods. Pulling up plants reveals that roots have been chewed off about an inch below the soil line. Sifting through the soil below the plants may reveal the whitish crescent-shaped grubs which can range in size from 3/8 inch to almost 1 ½ inches long, with six legs near the head and a swollen rear-end. The two most effective periods to treat plantings for grubs are in the spring prior to when they pupate (May) and in the late summer when the next generation is actively feeding (late August). Materials should be applied with plenty of water to moist soil to be sure they reach the root zone. Materials currently registered for control of grubs include Platinum® and Admire Pro®. Parasitic nematodes can also provide control of grubs and should be applied with similar timing. Nematodes are very sensitive to ultraviolet light and dehydration and must be applied with lots of water. See the New England Small Fruit Management Guide for sources of parasitic nematodes.

Strawberry rootworm (not root weevil) is a small (1/8″) dark brown to black beetle which feeds on strawberry foliage, causing it to look skeletonized. The small larvae feed on strawberry roots, further weakening the plant. Adult feeding damage on the leaves usually occurs in late July through August. Heavy rootworm feeding weakens strawberry plants so control is warranted when injury is noticed.

Strawberry Rootworm Beetle

Strawberry Rootworm Beetle, photo by James Dill

Potato Leafhopper

Potato Leafhopper, photo by James Dill

Keep a lookout for potato leafhoppers, which can weaken strawberry plants and spread disease. The potato leafhopper does not overwinter in Maine, but must fly in from southern states. These small, bullet-shaped insects feed on plant sap from the undersides of leaves, causing the leaves to become curled, stunted and yellow-streaked. Symptoms are often first noticed in new strawberry plantings, but leafhoppers will also infest older plantings and a variety of vegetables, flowers and fruit crops. To scout for leafhoppers, brush the leaves of the plants with your hand. The small, whitish adults can be seen flying off the plant. Examine the underside of some injured leaves. Look for small, light green leafhopper nymphs. They are about 1/16 inch long. When touched, they will crawl sideways in a crab-like manner. Controls for potato leafhoppers include malathion, carbaryl or Provado®.

MITES
Two-spotted spider mites can increase significantly during the summer. Continue to take leaf samples for spider mites throughout the summer. If more than 25% of a 60-leaf sample has mites, controls should be applied. Summer is an ideal time to use predatory mites to control pest mites, because they prefer warm temperatures, and there is less chance of an insecticide spray that might kill them. Amblyseius fallacis can provide good control of two-spotted spider mites when they are released at a rate of about 10,000 mites per acre. Predator mite releases should only be made after a spider mite infestation has been found in the field. Releasing predators into a clean field will often result in them dying, due to a lack of food. See the New England Small Fruit Management Guide for sources of predatory mites.

Two-spotted Spider Mites

Two-spotted Spider Mites, photo by David Handley

Cyclamen Mite Damage on Strawberry Plant

Cyclamen Mite Damage on Strawberry Plant, photo by David Handley

Cyclamen mites: If your field had cyclamen mite symptoms this spring, summer is a good time to control them. Plants showing weak growth and yellow, crinkled leaves may be infested with cyclamen mite. These mites are very small and reside down in the crown of the strawberry plant feeding on the developing leaves. They are very hard to see, even with magnification. Miticides such as Thionex®, Kelthane® or Portal® can be effective, but must be applied with lots of water to be sure that the material is carried down into the crowns.

WEEDS
Weeds can become a big problem during the summer because they are often forgotten among all the other demands on our time and because of limited control options. However, the importance of good weed management should not be underestimated. Keeping weeds under control this summer will prevent future infestations. Here’s a summary of weed control options for strawberries:

  1. Cultivation: Following renovation, cultivation between strawberry rows can provide effective temporary control of annual weeds. Several types of cultivators are available which will work well in strawberry beds. Cultivators can also be used to help sweep runners into the plant rows.
  1. DCPA (Dacthal®): A pre-emergent herbicide used in the early spring, late fall or after renovation. It offers good short-term control of some annual broadleaf weeds and grasses. It is weak on ragweed, galinsoga, smartweed, shepherd’s purse and mustard. Its action will be improved if worked into the soil by irrigation or light cultivation, and it tends to work best in lighter, warmer soils. This may be used as an alternative to terbacil or napropamide when there is a high risk of plant injury from those products.
  1. Napropamide (Devrinol®): A pre-emergent herbicide which provides good control of annual grasses, volunteer grains and some broadleaf weeds. It is typically applied just before mulching in the fall. Split applications have become popular due to the loss of other pre-emergent herbicides, e.g. half maximum rate application after renovation or in late summer after desired daughter plants have rooted, and a second half rate application once the strawberry plants are dormant. Napropamide should be activated by irrigation, rainfall or light cultivation within 24 hours of application. Repeated long-term use of this material, i.e. with no crop rotation, may eventually result in poor daughter plant establishment, due to rooting inhibition.
  1. Terbacil (Sinbar®): An effective pre-emergent herbicide with some post-emergent activity, which should be applied at renovation time – after mowing and tilling the beds, but before new growth begins. A second application can be made in late fall, after the plants are dormant. No more than 6 oz. may be applied in a single application, and no more than 8 oz. may be applied in one season. An example of one season’s use could be 5 oz. applied at renovation and 3 oz. applied in the late fall, the latter in addition to napropamide or DCPA. Terbacil can cause injury to strawberry plants. It is important to determine appropriate rates for each location.
  1. Clopyralid (Spur®): One application per crop per year following harvest to emerged weeds. Apply uniformly in a minimum of 10 gallons of water per acre. Do not tank mix with other herbicides. Offers control of clover, dandelion and thistle.
  1. Sethoxydim (Poast®): A post-emergent herbicide for control of actively growing grasses. It will not control broadleaf weeds. It should not be applied when grasses are under stress, e.g. drought, or on unusually hot, humid days. Do not use sethoxydim within 6 weeks of terbacil (Sinbar®) applications, to avoid leaf injury. Sethoxydim should be used in combination with a crop oil concentrate. Do not tank mix with 2, 4-D.
  1. Clethodim (Arrow®, Prism®, Select®): A post-emergent herbicide, similar in activity to Poast®, for control of actively growing grasses. It will not control broadleaf weeds. It should not be applied when grasses are under stress, e.g. drought, or on unusually hot, humid days. Clethodim should be used in combination with a crop oil concentrate.
  1. Paraquat (Gramoxone Inteon®): A contact herbicide for post-emergent control of most annual weeds and suppression of many perennial weeds. Paraquat will injure or kill strawberries, so applications are made between rows only, with a sprayer shielded to protect the strawberries. It should be used in combination with a nonionic surfactant. Paraquat should not be applied within 21 days of harvest or more than three times in one season.
  1. Pelargonic Acid (Scythe®): A contact herbicide for post-emergent control of most annual weeds and suppression of many perennial weeds. Scythe® will injure or kill strawberries, so applications are made between rows only, with a sprayer shielded to protect the strawberries. This product has a relatively low toxicity and no residual soil activity. It has a strong, unpleasant odor.
  1. 2,4-D Amine (Formula 40®, Amine 4): A post-emergent herbicide effective on most broadleaf perennial weeds. It will not control grasses, nor offer any pre-emergent control. 2,4-D should be applied immediately after harvest is complete if emerged broadleaf weeds are a problem. After application, the bed should be left undisturbed for three to five days, before mowing the leaves off the plants. This allows time for the material to be taken in by the weeds. This material can also be used when the plants are dormant (late fall or early spring) to control winter annuals and biennials. Fall applications may result in injury to the strawberries if the plants are not completely dormant. Do not tank mix 2,4-D with sethoxydim (Poast®).
  1. Flumloxazin (Chateau®): A pre-emergent herbicide for control of broadleaf weeds, including dandelion and shepherd’s purse. For use in the fall when plants are dormant for control of weeds the following spring.
  1. Pendimethalin (Prowl H20®): A pre-emergent herbicide that may be applied as a band with a shielded sprayer between the rows of strawberries. No weed control will be provided within the plant rows, and contact of this product on the strawberry plants will cause injury. May not be applied within 35 days of harvest.

The use of herbicides alone rarely gives complete weed control. Some hand weeding will be necessary. To provide good weed control throughout the life of a strawberry bed, growers should concentrate on crop rotation and good pre-plant weed control.

Strawberry Bed Renovation Review

Bed renovation should begin as soon after harvest as possible. The earlier the beds get renovated, the more time runner plants have to develop, which means larger crowns and more flower buds for next year. Early renovation also improves weed management by tilling in many weeds before they go to seed, and can help with insect and foliar disease control by interfering with life cycles at a critical stage of development. The first step in the bed renovation process is to determine which beds should be carried over for another year and which should be plowed down and put into a crop rotation. Beds that did not suffer much from winter injury, had good production and a good plant stand with no major weed, insect or disease problems should be carried over for another year. Beds that do not meet these criteria should be plowed down and seeded to a suitable cover crop to reduce weed, insect and disease problems that have developed, and to increase soil organic matter content. Ideally, beds that are plowed down should be rotated out of strawberries for at least three years. If properly managed, crop rotation will greatly reduce pest problems and improve the vigor and longevity of strawberry beds without the need for soil fumigation.

Strawberry Bed Renovation

Strawberry Bed Renovation, photo by David Handley

Renovating a strawberry bed is basically a thinning process to promote healthy new growth that can support a good crop next spring. While some parts of the following renovation scheme may be modified for individual situations, all beds should undergo the following steps once harvest is complete.

  1. Broadleaf weed control: If perennial broadleaf weeds such as dandelion, shepherd’s purse, daisy or goldenrod are a problem and/or a high population of annual broadleaf weeds such as lambsquarters, sorrel or pigweed are present, hand-pull as many as possible, especially within the plant rows, and/or apply 2,4-D amine (Formula 40®), or clopyralid (Spur®).
  1. Leaf mowing: Four to five days following the 2,4-D application (or immediately if 2,4-D was not applied) mow off the leaves of the strawberries about 1 ½ inches above the crowns. If the planting is weak, it is recommended that this step of the renovation process be skipped.
  1. Fertilization: Apply 40 to 60 pounds of actual nitrogen per acre (use the higher rate on sandy soils and fields where growth has been weak). Phosphorus and potassium applications should be made according to soil test recommendations. Soil testing kits and information are available from your county Cooperative Extension office.
  1. Plant thinning: For the single matted row system, strawberry plant rows should not be any wider than 24 inches. After mowing off the leaves, till the sides of the rows to narrow the beds back to a width of 12 to 18 inches. Use the wider setting for varieties that tend to throw few runners or any fields experiencing drought stress. Set the tiller so that it incorporates the mowed leaves and spreads about one inch of soil over the remaining crowns at the same time. This will reduce leaf disease and mite problems, and help stimulate new root growth on the remaining plants.
  1. Pre-emergent weed control: To control annual weeds, apply terbacil (Sinbar® 80WP) according to label directions (2 to 6 oz. per acre). Be sure to follow all label precautions. To avoid plant injury, do not use terbacil if you do not intend to mow off the leaves. Napropamide (Devrinol®) or DCPA (Dacthal®) may be used as an alternative to terbacil at this time, as described below. If you are not using herbicides, regular cultivation, before weeds are more than 2” tall, will be needed throughout the summer.
Strawberry Irrigation

Strawberry Irrigation, photo by David Handley

  1. Subsoiling: Soil compaction caused by tractor and picker traffic in the field can cause soil drainage problems and interfere with good root development. Using a subsoiling blade between the rows will break up compacted layers of soil and improve water infiltration. Subsoiling is best done late in the renovation sequence to prevent interference from straw and crop residues.
  1. Irrigation: To encourage rapid plant growth and get the most out of fertilizers and herbicides, irrigate the beds regularly. Strawberries will grow best if they receive 1 ½ inches of water per week during the growing season.

Don’t forget your plants once these renovation steps are completed. Check the strawberry fields regularly during the summer for pest problems. Finding and managing problems early can prevent major problems next spring. Pay close attention to the following items.

NUTRITION
Following the application of 40 to 60 pounds of actual nitrogen at renovation, another 20 pounds of nitrogen should be applied in mid- to late-August to stimulate flower bud development. One way to determine the nutrient status of strawberry plants during the summer is to have a leaf tissue analysis done. Tissue analysis offers a view of what is happening within the plant, and can spot any nutrient deficiencies. In combination with regular soil tests, tissue analysis will provide a complete picture of a field’s fertilizer needs. For more information about tissue analysis contact: Analytical Lab, 5722 Deering Hall, Rm. 407, University of Maine, Orono, ME 04469-5722, telephone: 207.581.2945.

Pest Management for Day-Neutral Strawberries

Most of the important pests that damage June-bearing varieties can be as much or more of a problem on day-neutral types. Because day-neutral strawberries will have buds, flowers and fruit all occurring at the same time, it is critical to pay close attention to the required number of days to harvest after a pesticide application, to be sure you can safely harvest ripe fruit while still protecting buds and blossoms. Some of the more important pests are listed below, along with currently recommended pesticides and days to harvest as stated on current labels.

Male and Female Spotted Wing Drosophila Flies

Male (left) and Female (right) Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

Spotted wing drosophila (Drosophila suzukii) is a new pest, which is likely to be a concern for day- neutral strawberries, fall raspberries and blueberries. This is a small fruit fly, similar to those that hover around the bananas in your kitchen. However, this species will lay its eggs on fruit before it ripens, resulting in fruit that is contaminated with small white maggots just as it is ready to pick. Infested fruit quickly rots and has no shelf life. This insect can complete a generation in under two weeks, with each adult female laying hundreds of eggs. Therefore, millions of flies can be present soon after the introduction of just a few into a field. Frequently repeated insecticide sprays (1 to 2 per week) may be needed to prevent infestations once the insect is present in a field. Spotted winged drosophila can successfully overwinter here, although it may not build up to damaging levels until late in the summer. We have set out monitoring traps for spotted winged drosophila in fruit plantings around the state to determine the activity of this pest in Maine. However, these traps may not provide adequate early warning, i.e. when we find them in a trap they are probably already established in the field. Products that provide good control of drosophila on strawberries include Radiant®, Brigade®, Danitol®, malathion and Assail®. Keeping fields clean of over-ripe and rotten fruit will also help reduce the incidence of this insect. For more information on identifying spotted wing drosophila and updates on populations around the state, visit our SWD blog. Other spotted wing drosophila resources include Michigan State University’s website, Penn State’s website, and University of New Hampshire’s website.

Tarnished plant bug: This is one of the most prevalent and persistent pests of day-neutral strawberries, because summer flowering coincides with peak populations of this insect. Adult and nymph stages feed on the flowers and developing fruit, causing them to have seedy ends and other malformations. Regular insecticide applications are often required to keep the damage in check. Scout the flower clusters for adults and nymphs often to determine if controls are necessary. Insecticide products for tarnished plant bug are included in the following table.

Tarnished Plant Bug on Strawberry

Tarnished Plant Bug on Strawberry Flower, photo by David Handley

Tarnished Plant Bug
Product Days to Harvest
Brigade® 0
Pyganic® 0
Assail® 1
Dibrom® 1
Rimon® 1
malathion 3

 

Two-spotted spider mites: Mites can become a problem during the summer when the growing conditions are warm and dry. In addition to infesting the leaves, mites can move onto the fruit, reducing marketability. Plants that are drought-stressed, over fertilized with nitrogen, or prone to dust covering, e.g. growing beside a dirt road, are especially prone to mite infestation. Predatory mites can be an effective means to control spider mites and keep them in check over the season. Releases should only be made when spider mites are present in the field to provide the predators with a source of food. Most of the products labeled for controlling spider mites will also kill predatory mites; so do not use these products after predators have been released. Scout for mites often during the season by examining the undersides of the leaves. Control is warranted if more the 25% of leaves examined have mites.

Two-spotted Spider Mites

Two-spotted Spider Mites, photo by David Handley

Two-Spotted Spider Mites
Product Days to Harvest
Brigade® 0
Zeal® 1
Vendex® 1
Acramite® 1
Danitol® 2
Agri-Mek® 2
Oberon® 3
Savey® 3
Kelthane® 3

Potato leafhoppers, sap beetles, thrips and spittlebugs may also become problems on day-neutral strawberries, but are less frequently observed than tarnished plant bug and spider mites. Recommendations for these insects can be found in the current edition of the New England Small Fruit Management Guide.

Gray Mold on Strawberries

Gray Mold on Strawberries, photo by James Dill

Foliar and fruit diseases also need to be managed on day-neutral strawberries, and should be controlled in much the same way as they are for June-bearing varieties. Most of the fungicide products labeled to control gray mold, powdery mildew, leaf spot and leaf scorch have either zero or one day to harvest, so protecting blossoms at the same time as fruit is near harvest should not be a problem; but be sure to check labels carefully and schedule your sprays and harvests accordingly. Anthracnose fruit rot can be especially troublesome for day-neutral strawberries, because it grows well under warm conditions and spreads by splashing water, which is encouraged on plastic mulch. Fungicides registered for control of anthracnose include Cabrio®, Abound®, Pristine® and Switch®, all of which have zero days to harvest restriction.

Visit the 2014-2015 New England Small Fruit Management Guide online for more detailed pest information.

Hold the Dates:
Fruit & Vegetable Growers Field Day at Highmoor Farm: Wednesday July 22, 9:00 a.m. to 3:00 p.m. Call 207.933.2100 or visit the Highmoor Farm Field Day website for registration information. Please register early!

New England Vegetable & Fruit Conference will be held on December 15-17 in Manchester, NH. Details and registration information are coming soon. Please visit the NEVFC website.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management
P.O. Box 179                             491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                           1.800.287.0279

Where brand names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against products with similar ingredients. Always consult product label for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment. A Member of the University of Maine System


 

Sweet Corn Newsletter No. 3 – July 10, 2015

July 10th, 2015 12:12 PM

Sweet CornSweet Corn IPM Newsletter No. 3 – July 10, 2015
Click on photos to enlarge.

FIRST FALL ARMYWORM MOTHS CAUGHT

Corn Earworm Threatens Early Silking Corn

SITUATION
More early silking corn is showing up in southern Maine. With good growing conditions and adequate moisture, it won’t be long now before we see some native sweet corn on the stands. Later pre-tassel corn is being side-dressed at many sites this week. Although insect pressure has been low to moderate at our scouting sites this week, we did catch our first fall armyworm moths of the season, indicating that this pest may soon be threatening corn, in addition to European corn borer and corn earworm.

European Corn Borer Larvae on Pre-tassel Stage Corn

European Corn Borer Larvae on Pre-tassel Stage Corn, photo by David Handley

European corn borer: Moth catches were fairly light and scattered around the state this week, with the exception of a field in Nobleboro, where 47 moths were caught, far exceeding the silking corn threshold of 5 moths. However, this field is also on a spray regime for corn earworm, so no additional sprays should be required. European corn borer feeding damage was over threshold in pre-tassel to tasseling fields in Biddeford, Dayton, Nobleboro, No. Berwick, Wayne and Wells this week. Sprays applied at pre-tassel are most effective because the larvae are usually more exposed at that time.

Corn earworm: Trap captures were a bit higher and more widely distributed around the state this week, with more northern sites now starting to pick up a few moths. A 6-day spray interval was recommended for silking fields in Cape Elizabeth, Dayton, North Berwick and Wales. A 5-day spray interval was recommended for silking fields in Lewiston and Nobleboro.

Fall armyworm: The first moths of the season were caught in our traps in southern Maine this week. These moths will be laying eggs in young cornfields, and we should expect to find feeding damage soon. Fall armyworm caterpillars leave large ragged holes in the corn leaves and lots of sawdust-like waste within the whorl and developing tassels. When feeding damage is found, we combine the number of infested plants with any showing injury from European corn borer, and would recommend a spray if the total feeding damage exceeds the 15% of the number of plants scouted. In silking fields, fall armyworm larvae may enter the ears through the silk channel, leaving little visible damage to the plant. For that reason, when more than 3 fall armyworm moths are caught in pheromone traps in a week, a spray is recommended for all silking corn in a field. Only one field in Biddeford was over the threshold for silking corn this week. However, that field is not yet in silk, so no spray was recommended.

Fall Armyworm Moths

Fall Armyworm Moths (female right, male left), photo by James Dill

Squash Vine Borer Larva

Squash Vine Borer Larva, photo by Jeffrey Hahn, Univ. of Minnesota Extension

Squash vine borer moths were caught in pheromone traps in, Biddeford, Cape Elizabeth, Dayton, Oxford and Wells this week. The threshold of five moths per week was exceeded in Cape Elizabeth, Dayton and Wells. This pest can cause significant damage to summer squash, winter squash and pumpkins. The larvae bore into the base of the plants, causing vines to wilt and eventually collapse. See the 2014-2015 New England Vegetable Management Guide for control options.

Japanese beetles are starting to appear in southern and mid-state areas. These insects often find their way into cornfields and feed on the silks of developing ears, causing poor tip fill. Sprays for corn earworm (except Bt’s) will often control Japanese beetle as well.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                             491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                           1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 0 0 0 5% No spray recommended
Biddeford 1 0 3 18% One spray recommended for ECB in pre-tassel corn
Bowdoinham 0 0 0 0% No spray recommended
Cape Elizabeth I 0 0 0 0% No spray recommended
Cape Elizabeth II 2 0 1 0% 6-day spray interval recommended on all silking corn
Charleston 0 0 0 0% No spray recommended
Dayton I 2 0 0 6-day spray interval recommended on all silking corn
Dayton II 4 1 0 16% 6-day spray interval recommended on all silking corn
Farmington 1 0 0 1% No spray recommended (no silking corn)
Garland 0 1 0 1% No spray recommended
Levant 0 0 0 2% No spray recommended
Lewiston 4 2 1 0% 5-day spray interval recommended on all silking corn
New Gloucester 1 0 0 0% No spray recommended
Nobleboro 5 47 0 25% 5-day spray interval recommended on all silking corn
No. Berwick 2 0 2 33% 6-day spray interval recommended on all silking corn
Oxford 0 0 0 4% No spray recommended
Palmyra 0 3 0 0% No spray recommended
Sabattus 0 4 0 7% No spray recommended
Wales 2 2 0 0% 6-day spray interval recommended on all silking corn
Warren 0 0 0 5% No spray recommended
Wayne 0 1 0 27% One spray recommended for ECB in pre-tassel corn
Wells I 0 0 0 17% One spray recommended for ECB in pre-tassel corn
Wells II 0 1 0 1% No spray recommended

CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

 

Sweet Corn IPM Newsletter No. 2 – July 3, 2015

July 2nd, 2015 4:22 PM

Sweet CornSweet Corn IPM Newsletter No. 2 – July 3, 2015

Click on photos to enlarge.

CORN EARWORM MOTHS MORE WIDESPREAD

European Corn Borer Feeding Over Threshold in Pre-Tassel Fields

SITUATION
Cool night temperatures through much of the state have slowed corn development a bit this week, although overall growth looks very good. More early fields in southern Maine are coming into tassel and a couple of fields started under plastic or row covers are in silk. Both European corn borer and corn earworm are now active in cornfields in much of the state. These are especially a threat to early silking fields, which growers often spray lightly, if at all; assuming these pests aren’t yet present in damaging numbers.

European Corn Borer Damage on Pre-tassel Stage corn

European Corn Borer Damage on Pre-tassel, photo by David Handley

European corn borer: Moth catches are spotty around the state this week with a little less than half of the sites now catching moths. A field in Nobleboro was over threshold of 5 moths per week; but there was not yet any silking corn in the field, so no spray was recommended. European corn borer feeding damage was over the 15% threshold within pre-tassel fields in North Berwick and Livermore Falls. Otherwise, feeding damage has been very light.

Corn earworm: More locations captured corn earworm moths this week, although numbers are still low, and most fields do not yet have any silking corn that could be threatened by this pest. When more than one corn earworm moth is found at a site, all silking corn in the fields should be protected with a spray. Additional sprays are based on the average number of moths caught per week or per night (see table below). Only one field in Dayton had moths over threshold and early silking corn. A 6-day spray interval was recommended at that location, based on a weekly moth catch of 2.

Fall armyworm: No moths have been captured in our pheromone traps this week, and no feeding damage has been reported. This is usually the last major corn pest to arrive in Maine from southern overwintering sites.

Squash vine borer moths were caught in pheromone traps in Dayton and Wells this week. George Hamilton in New Hampshire has been reporting high numbers of moths this week. This pest threatens summer squash, winter squash and pumpkins. Unlike many moths, squash vine borer moths fly during the day. They are black and orange and resemble wasps. The moths lay eggs at the base of squash plants. The larvae bore into the base of the plants, causing vines to wilt and eventually collapse. The control threshold for squash vine borer moths is 5, which was exceeded at the site in Dayton this week. See the 2014-2015 New England Vegetable Management Guide for control options.

Two Squash Vine Borer Moths

Two Squash Vine Borer Moths, photo by Jeffrey Hahn, Univ. of Minnesota Extension

drosophila trap

Drosophila Trap, photo by David Handley

Spotted wing drosophila: The first captures of a spotted wing drosophila are being reported from southern New England this week. These small fruit flies can cause serious fruit losses in raspberries, blueberries and other soft fruits. The flies only attack fruit that has begun to ripen. We will be setting out traps for spotted wing drosophila in Maine berry fields over the next two weeks. We don’t expect populations to reach damaging levels for at least a few more weeks. For more information visit our web blog.

Highmoor Farm

Highmoor Farm, photo by David Handley

Highmoor Farm Field Day
The Highmoor Farm Field Day will be held on Wednesday, July 22, 2015. Visit the Highmoor Farm Field Day blog for more information.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                              491 College Avenue
Monmouth, ME 04259           Orono, ME 04473
207.933.2100                            1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 5 2 0 0% No spray recommended (no silking corn)
Biddeford 0 0 0 5% No spray recommended
Bowdoinham 0 3 0 No spray recommended
Cape Elizabeth I 0 0 0 0% No spray recommended
Cape Elizabeth II 1 0 0 1% No spray recommended (no silking corn)
Dayton I 2 4 0 6-day spray interval recommended on all silking corn
Dayton II 0 3 0 0% No spray recommended
Lewiston 1 0 0 0% No spray recommended (no silking corn)
Livermore Falls 0 6 0 31% One spray recommended for ECB on pre-tassel corn
New Gloucester 0 0 0 No spray recommended
Nobleboro 2 34 0 0% No spray recommended (no silking corn)
No. Berwick 1 0 0 41% One spray recommended for ECB on pre-tassel corn
Poland Spring 0 0 0 1% No spray recommended
Warren 0 0 0 0% No spray recommended
Wells I 2 0 0 1% No spray recommended (no silking corn)
Wells II 0 0 0 0% No spray recommended

CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

 

 

 

Sweet Corn IPM Newsletter No. 1 – June 26, 2015

June 29th, 2015 9:26 AM

Sweet CornSweet Corn IPM Newsletter No. 1 – June 26, 2015
Click on photos to enlarge.

2015 SWEET CORN PEST SEASON BEGINS!

European Corn Borer and Corn Earworm Moths Active in Early Fields

The 2015 University of Maine Cooperative Extension Integrated Pest Management (IPM) program for sweet corn is underway. More than twenty volunteer farms are serving as pest monitoring and demonstration sites, with fields in North Berwick, Wells, Dayton, Cape Elizabeth, New Gloucester, Poland Spring, Auburn, Lewiston, Sabattus, Nobleboro, Warren, Monmouth, Wales, Wayne, Oxford, Farmington, Levant, Stillwater, Garland and East Corinth. Pheromone traps have been set up at these farms to monitor the adult (moth) stages of European corn borer, corn earworm and fall armyworm, and we are scouting the fields for feeding injury by insect larvae. We will share the information we collect at these sites along with management recommendations every week during the season through this newsletter and blog. If you would prefer to receive this newsletter via e-mail, give us a call at 207.933.2100 or send an e-mail message to: pamela.stpeter@maine.edu.

Corn Field at Whorl Stage

Corn Field at Whorl Stage, photo by David Handley

SITUATION
A dry early spring and warm temperatures in May allowed farmers to get some early cornfields planted and growing. Cooler temperatures this month have slowed development of young plants, but overall growth looks good. Some very early corn, started under plastic or row covers is already beginning to silk in southern Maine. Most early fields are at late whorl and early pre-tassel. Some weather fronts coming up from the south have apparently brought some corn earworm in the state, and European corn borer moths are already active in some fields. Growers with early corn should be on the lookout for feeding damage in their fields.

European corn borer: Moths have been found in many of our pheromone traps this week, suggesting that this insect is off to an early start and is now laying eggs in young cornfields. The egg masses are small and look like a clump of overlapping fish scales on the undersides of corn leaves. European corn borer overwinters in Maine, and is usually the first pest to become a significant problem. To monitor corn borer, we scout 100 corn plants in each field, examining twenty plants in a row at five different locations. This provides a good estimate of the total amount of injury in a field.

In the early stages, European corn borer feeding damage looks like small “pinholes” in the leaves. Whorl stage corn only needs to be sprayed if fresh feeding injury is found on 30% or more of the plants scouted in a field. Once the corn reaches the pre-tassel stage, the control threshold is lowered to 15% because larvae feeding on the later stages are more likely to move into the ears. On the tassels, feeding damage first appears as chewing and brown waste found in the small florets. After the tassel has emerged from the stalk, the larvae chew into the stalk just below it, often causing the tassel to fall over. Sprays during the pre-tassel stage, when both moths and larvae are present, reduce the opportunity for larvae to move into the stalks and ears of the plant. Once the larvae are in the stalks they are protected from sprays. Good spray coverage of the entire plant provides the most effective kill of larvae as they move from one part of the plant to another. Rotating the type of insecticide used also improves control. Materials registered for controlling European corn borer include Bacillus thuringiensis products (XenTari®, Dipel DF®), Avaunt®, Coragen®, Warrior®, Lannate®, Baythroid®, Asana®, Radiant®, Delta Gold®, Mustang®, Sevin XLR® and Larvin®.

Thus far, we have only found corn borer feeding injury in a pre-tassel field in North Berwick. But the presence of moths in other locations suggests that feeding injury will soon become more widespread. Growers should start scouting whorl stage corn for feeding injury now. Once corn reaches the silk stage, sprays may be based on the number of corn borer moths caught in pheromone traps rather than feeding injury. European corn borer moths will lay eggs on flag leaves of silking corn, and the larvae can move into the ears without leaving visible feeding injury that would be noticed when scouting. If more than five moths are caught during a week in a field with silking corn, a spray is recommended. One field in Dayton had early silking corn this week, and was over the spray threshold for moths in the pheromone traps. Fields in Lewiston, Nobleboro and Wayne were also over the control threshold, but there was no silking corn at those sites, so no spray was recommended. Varieties of corn genetically modified to produce the Bt toxin (e.g. Bt corn, Attribute® varieties), should not need to be sprayed to control European corn borer.

European Corn Borer Moth

European Corn Borer Moth, photo by David Handley

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Corn earworm: Moths were caught in pheromone traps at two coastal sites this week (Nobleboro and Warren). This is a relatively early arrival of corn earworm in Maine, but because most locations do not yet have silking corn, they pose very little threat at this time. Corn earworm generally appears in Maine in early July, but the actual date varies greatly. The arrival of this pest is only a concern for fields with corn in the silk stage. Fields not yet in silk do not need to be protected from corn earworm. When corn earworm moths start being caught at a site, all silking corn in the fields should be protected with a spray. These moths lay eggs on the fresh silks and the larvae move directly into the ears of corn. When corn earworm moths cannot find silking corn to deposit their eggs on, they may lay eggs on the leaves of younger corn. The larvae will feed on the foliage and tassels, similar to armyworm, until the ears become available. When larvae are found feeding on younger corn, the damage is accounted for, along with any borer or armyworm damage, to determine if a spray is warranted.

Fall armyworm: This is usually the last serious corn insect pest to arrive in Maine. The moths must fly in from southern over-wintering sites, and tend to lay their eggs on the youngest corn available. When the larvae hatch, they chew large, ragged holes in the leaves, and may bore into developing ears. Larvae may also move into the ears through the silk channel, behaving similarly to corn earworm. Pheromone trap catches will indicate if there is a threat to silking corn. However, corn will usually be on a spray program for corn earworm when fall armyworm is present, and both insects would be controlled. We have not yet caught any fall armyworm moths in our pheromone traps.

Harstack Trap

Harstack Trap, photo by David Handley

Do-It-Yourself IPM: To get the most accurate information about the pest situation on your farm you should monitor the fields yourself on a regular basis. Pheromone traps and lures are available that can give you an accurate, early warning of the arrival of all of the major insect pests. Traps and lures can be purchased from pest management supply companies such as Gempler’s (Tel. 1.800.382.8473) or Great Lakes IPM (Tel. 517.268.5693).

To learn more about IPM scouting techniques, insect identification and control thresholds, order the fact sheet Managing Insect Pests of Sweet Corn available from the University of Maine Cooperative Extension. Color pictures are provided to help with insect identification, and a chart with spray thresholds is supplied to post near your sprayer for easy reference. You can download a copy from the Cooperative Extension Publications website at or call the Pest Management Office at 1.800.287.0279.

Hold the Date!
Highmoor Farm Field Day will be held on Wednesday, July 22, 2015. Visit the Highmoor Farm Field Day blog for more information.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                              491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                            1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations /
Comments
Auburn 0 4 0 0% No spray recommended
Biddeford 0 0% No spray recommended
Bowdoinham 0 0 0 No spray recommended
Cape Elizabeth I 0 2 0 0% No spray recommended
Cape Elizabeth II 0 0 0 0% No spray recommended
Dayton I 0 8 0 0% One spray recommended for ECB on silking corn
Dayton II 0 0 0 0% No spray recommended
Farmington 0 3 0 0% No spray recommended
Lewiston 0 8 0 0% No spray recommended (no silking corn)
New Gloucester 0 0 0 0% No spray recommended
Nobleboro 3 41 0 0% No spray recommended (no silking corn)
No. Berwick 0 4 0 38% One spray recommended for ECB on pre-tassel corn
Oxford 0 0 0 0% No spray recommended
Poland Spring 0 0 0 0% No spray recommended
Sabattus 0 1 0 0% No spray recommended
Wales 0 0 0 0% No spray recommended
Warren 1 0 0 0% No spray recommended (no silking corn)
Wayne 0 5 0 0% No spray recommended (no silking corn)
Wells I 0 0 0 0% No spray recommended
Wells II 0 0 0 0% No spray recommended

CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

Highmoor Farm Field Day – July 22, 2015

June 24th, 2015 9:32 AM

Highmoor Farm Field Day

Tall spindle apple trees

Tall Spindle Apple Trees, photo by Renae Moran

Wednesday, July 22, 2015
9:00 AM to 3:00 PM
Highmoor Farm, 52 US Route 202, Monmouth, Maine 04259
Registration fee is $20.00 (includes lunch). Preregistration is strongly encouraged.

Contact Pam St. Peter at pamela.stpeter@maine.edu or 207.933.2100 to preregister. Please register by July 15 to give us an accurate count for lunch.

The Maine State Pomological Society and Maine Vegetable and Small Fruit Growers Association will be joining with the Maine Agricultural and Forest Experiment Station and the University of Maine Cooperative Extension to hold a public field day at Highmoor Farm in Monmouth on Wednesday, July 22, 2013, rain or shine.

High Tunnel Tomatoes

High Tunnel Tomatoes, photo by Danielle Murray

This year’s field day will include tours of current research projects in tree fruit, including a new tall spindle orchard, and projects in vegetables and berries, including grape and raspberry variety trials, sweet corn evaluations, pumpkin trials, broccoli evaluations, as well as reduced tillage in organic systems and permanent beds, high tunnel tomatoes, irrigation and compost application in high tunnels, trellis installation and DA meters.

Growers are welcome to attend the whole day, or may come for just the morning or afternoon programs and tours. Whichever you decide, please plan to be there for lunch to share some time and informal discussion with fellow farmers, research and Extension staff and state officials.

Highmoor Farm is the Field Research Station for fruits and vegetables, and has been working with Maine farmers to improve crop production since 1909, when the farm was purchased by the state to carry out research on orchard practices. For more than 100 years, researchers at Highmoor Farm have helped to develop cultural techniques, new varieties and pest management practices to improve the success of Maine’s vegetable and fruit farmers.

AGENDA

9:00 AM Registration
9:30 AM Welcome and Opening Remarks
Fred Servello, Maine Agricultural & Forest Experiment Station Associate Director
John Rebar, University of Maine Cooperative Extension Director
9:45 AM How Changes in the Farm Bill May Impact our Business
Erin Roche, Maine Crop Insurance Education Program Manager
10:00 AM Using the DA Meter to Measure Fruit Ripeness and to Solve Honeycrisp Storage Problems
Larry Lutz, Scotian Gold Tree Fruit Specialist, Nova Scotia
10:30 AM Break
10:45 AM Making Your Farm Safe for Visitors and Employees
Maine Department of Labor SafetyWorks! Program
11:15 AM Maine State Pomological Society Business Meeting
Andy Ricker, President
Legislative Update
State Senator James Dill and State Representative Jeffrey Timberlake
12:00 PM Lunch
1:00 PM Concurrent Experiment Station Research Tours
Tree Fruit Tour –
Renae Moran, Glen Koehler, and special guests Larry Lutz, Scotian Gold Tree Fruit Specialist and Jorge Acero, Maine Department of Labor State Monitor Advocate for Migrant and Seasonal Farm Workers. Strategies for controlling bitter pit in Honeycrisp, the new tall spindle apple orchard, cold hardy plum varieties, and ladder safety. Scotian Gold is a cooperative in Nova Scotia with 55 grower-members representing 2,500 acres of apple trees.
Berry and Vegetable Tour –
David Handley and Mark Hutton. Pumpkin, sweet corn, broccoli and grape variety trials; pest update; and reduced tillage in organic systems and permanent beds; high tunnel tomatoes and strawberries; irrigation and compost application in high tunnels.
3:00 PM Adjourn


Thank you to our sponsors, Crop Production Services and Maine State Pomological Society.

Directions to Highmoor Farm, 52 US Route 202, Monmouth, Maine 04259 (207.933.2100)
Traveling North on I-95: Drive north on the Maine Turnpike (I-95) and take Exit 86 in Sabattus. Turn left onto Route 9/Middle Road. Travel about 2 miles on Route 9 East, then turn left onto Route 132. After 4.5 miles, turn left onto Leeds Junction Road. Travel about 2.8 miles, then turn right onto U.S. Route 202 and travel about 1.3 miles up the road until you see Highmoor Farm on the right.

Traveling South on I-95: Take Exit 109B in Augusta. Continue west on U.S. Route 202 and travel about 15 miles. Highmoor Farm will be on the left.


For more information about this or other workshops, please contact:

Renae Moran, Tree Fruit Specialist
University of Maine Cooperative Extension
Highmoor Farm
P.O. Box 179
Monmouth, ME 04259-0179
Tel. 207.933.2100, ext. 105.
rmoran@maine.edu


Any person with a disability who needs accommodations for this program should contact Pam St. Peter at 207.933.2100, or 1.800.287.8957 (TDD) to discuss any needed arrangements. Receiving requests for accommodations at least 10 days before the program provides a reasonable amount of time to meet the request; however, all requests will be considered.

Strawberry IPM Newsletter No. 6 – June 18, 2015

June 19th, 2015 11:24 AM

StrawberriesStrawberry IPM Newsletter No. 6 – June 18, 2015
Click on photos to enlarge.

STRAWBERRY HARVEST GETS UNDERWAY!

Crop Prediction: Good to Moderate

Situation: Harvest is underway in Southern Maine and more northern areas are soon to follow. We’ve been getting calls on bird damage, but otherwise the pest pressure has been very low in most fields this week. Fruit size, especially on secondary and later fruit appears to be smaller this year, which may be a result of our very dry spring and/or cold winter. Regardless, the overall quality looks good and yields look to also be good, especially in areas that received adequate rain or irrigation during the fruit development period. Our annual strawberry bed renovation issue will be posted in two to three weeks. In the meantime, we hope the information provided by the Strawberry IPM Newsletter has helped you make the best pest management decisions possible for your fields. Happy harvest!

Tarnished plant bug nymphs were only found in one field this week, and populations were below the management threshold. Overall, tarnished plant bug pressure has been very light this spring, and hopefully growers were able to reduce sprays as a result. However, if you are also growing day-neutral strawberries for a late summer and fall crop, begin scouting for tarnished plant bug as soon as the plants begin to flower. Tarnished plant bug populations are at their highest in the late summer, so damage on these fruit can be severe. Often control must occur when both flowers and nearly ripe fruit are present, so select insecticides with short residuals and days to harvest. Some examples include Assail®, Brigade®, Bifenture®, and Dibrom®.

Tarnished Plant Bug on Strawberry

Tarnished Plant Bug on Strawberry Flower, photo by David Handley

Two-spotted Spider Mites

Two-spotted Spider Mites, photo by David Handley

Two-spotted spider mite activity has been low in most fields throughout the season, despite dry conditions, which can promote their development. Mite populations can build up almost anytime, especially in hot, dry, dusty conditions; so growers should continue to scout for mites throughout the summer and be prepared to manage them if they build up after renovation. Spider mites can become a problem on day neutral strawberries in the late summer and fall, so scout these plantings regularly for mites.

Leaf diseases, including powdery mildew, leaf spot and leaf scorch, are at very low levels as we come into harvest. These diseases can pop up anytime during the season, so continue to be on the lookout throughout harvest and following renovation.

Leather rot (Phytopthora cactorum) and Anthracnose fruit rot (Colletotrichum acutatum) can be a problem on day-neutral strawberries ripening during the late summer and fall, especially following heavy rain showers and humid weather. Water splashing on the surface of plastic mulch can lead to the development and rapid spread of these diseases. Fungicides effective for gray mold may not provide control of leather rot and may not be very effective for anthracnose. Aliette®, Agri-Phos® or Phostrol® are recommended for leather rot, while Cabrio® and Pristine® are effective for anthracnose.

Review: Keeping Strawberries Fresh for Market
Strawberries are highly perishable and can fall into decay very rapidly if not handled properly. Train your pickers and sales people regarding how to keep the fruit in the best condition possible all the way from the field to the customers, in order to maintain the best quality and prolong shelf life. Pickers should be careful not to bruise fruit during harvest, and not to put damaged fruit into the containers. All harvested fruit should be cooled immediately to slow respiration. This will greatly extend shelf life and reduce the incidence of post-harvest fruit rots. Strawberries cool most efficiently if harvested early in the morning before they build up any field heat. Place fruit into refrigerated storage quickly and keep it out of direct sunlight. Fruit should be stored at 32° Fahrenheit and 95% relative humidity. Cold air should be moved through the boxes or flats of fruit with a circulating fan and/or exhaust fan to cool most efficiently. Placing a sheet of plastic over the trays in the cooler can reduce moisture build up on the berries. Temperatures lower than 32°Fahrenheit may freeze the fruit and ruin its fresh quality. A small, well-insulated building cooled with air conditioners and fans can provide effective temporary storage for strawberries. If you don’t have refrigeration facilities, keep the fruit as cool as possible by harvesting when air temperatures are cool, and keeping it out of direct sunlight. Transport the fruit to market as quickly as possible, and harvest only what you think you can sell in a day.

Girl with Quarts of Strawberries

Strawberry Harvest, photo by David Handley

Annual Pre-Harvest Checklist for Pick-Your-Own
It’s that time again! As harvest approaches, its time to make sure that your farm is ready to give your customers the best possible picking experience. Take our annual review below to evaluate your customer readiness.

√ A phone message with picking conditions and opening and closing times is regularly updated.

√ Signs to the farm are neat and easy to read.

√ There is easy access to the fields and plenty of parking.

√ Someone is ready to greet customers and offer parking instructions and directions to the field.

√ Access to the field is free of hazards.

√ Transportation is provided for the elderly and disabled.

√ The rules regarding picking are clearly posted.

√ Someone is in the field to show customers where to pick and to answer questions.

√ There are plenty of picking containers available.

√ Clean restroom and hand washing facilities are available.

√ Someone is available to help customers carry fruit out of the field.

√ The checkouts are fast and efficient.

√ Beverages are available.

√ Shade and seats are available for customers wanting to rest.

√ The help are friendly and knowledgeable.

A friendly, clean, and organized atmosphere will leave a lasting impression on your customers, encouraging them to come back and to recommend your farm to their friends.

Other Crops: Some blueberry fields are showing significant winter injury, including dead, dark brown or black shoots, usually at or near the top of the bushes. Pruning out such injury once the plants have started to grow does not appear to help the plants much. However, Phomopsis twig blight often infects blueberry branches through the cold-injured tissue. This fungus disease causes new shoots to suddenly wilt and turn black. Individual branches or canes on the bushes may also turn brown. This is referred to as “flagging”. Infected branches may be pruned out. Sterilize pruners before moving on to another bush to prevent further spreading the fungus. Lime sulfur sprays used prior to leafing out in the spring and some copper materials can help control Phomopsis. See the New England Small Fruit Management Guide for more details.

entrance to Highmoor Farm

Highmoor Farm, photo by Pam St. Peter

Hold the Date! Details Soon!
Highmoor Farm Field Day
Wednesday, July 22, 2015
52 US Route 202, Monmouth, Maine 04259

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management
P.O. Box 179                             491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                           1.800.287.0279

Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment. A Member of the University of Maine System.

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Strawberry IPM Newsletter No. 5 – June 12, 2015

June 12th, 2015 2:05 PM

StrawberriesStrawberry IPM Newsletter No. 5 – June 12, 2015
Click on photos to enlarge.

STRAWBERRY HARVEST GETTING STARTED IN SOUTHERN MAINE

Insect and Disease Activity Remains Low

Situation: Southern and mid-state fields remain pretty dry, while fields in the more northern and western part of the state have been getting some heavy showers this week. A few ripe berries are being picked in far southern Maine and some of those fields may open for pick-your own early next week. More northern growers are still about a week away. The pest situation remains fairly calm, although the spider mites may soon become more numerous, as should be expected with warm, dry weather.

Strawberry bud weevil or “clipper” activity is showing up on late blooming varieties, but most fields are beyond the full bloom stage. Thus, clipper no longer presents a serious threat. Remember that clippers will move onto raspberry and blackberry plants to lay eggs and clip buds once the strawberries have gone into bloom.

Large Tarnished Plant Bug Nymph

Third Instar Tarnished Plant Bug Nymph, photo by David Handley

Tarnished plant bug activity continues to be very low this week. No fields were found over threshold of 4 or more flower clusters infested per 30 sampled. Tarnished plant bug remains a threat throughout the bloom and petal fall stage, and should be scouted for regularly on the flower clusters and developing fruit. Insecticide options include malathion, Assail®, Brigade®, Bifenture®, Danitol®, and PyGanic®.

Two-spotted spider mite activity remains low in most fields, although one planting in Minot was over threshold with 25% of leaves sampled having mites. Mite populations should be expected to increase if warm dry conditions continue, so keep scouting for them.

Sap beetle on strawberry

Picnic Beetle (left) on Strawberry, photo by James Dill

Sap beetles and picnic beetles are sometimes a problem as we start harvesting berries. The 1/8-inch long, dark brown beetles chew small holes in ripening fruit, similar to slug injury. They may be seen in the holes they’ve chewed into ripe fruit, but often drop to the ground when disturbed. The best management strategy for sap beetles is good sanitation. Keep the field free of overripe fruit by picking often and thoroughly. Insecticide sprays for this pest can be effective, but should be a last resort during the harvest period. Brigade®, Assail®, Dibrom®, and PyGanic® are registered for control of sap beetles with pre-harvest intervals ranging from 12 to 24 hours. Read the product label carefully for this and other application instructions and restrictions.

Entrust® Insecticide May Lose Berry Registration
Dr. Richard Cowles of the Connecticut Agricultural Experiment Station recently shared a letter he received from Dow AgroSciences stating that the registration of Entrust® insecticide (active ingredient spinosad) may be withdrawn by the company due to reports of misuse (primarily overuse) by growers, which could threaten the viability of the product by encouraging the development of insect resistance to it. Entrust® has been a very important tool for the management of spotted wing drosophila (SWD), especially for organic berry growers, as the product is Organic Materials Review Institute (OMRI) approved. Dr. Cowles states “This is not an idle threat to withdraw sales of Entrust® to New England states.  Abuse of Conserve SC® by greenhouse growers in the Southeast led to widespread flower thrips resistance, whereupon Dow withdrew marketing of that product to that region.  The problem that I see is that there currently are very few effective proven alternative options to spinosad available to organic growers, besides frequent clean harvesting of crops and use of exclusion netting (for certain crops).”

All berry growers should intensively monitor for SWD adult activity with effective traps and baits, and only consider insecticide sprays when both (a) SWD adults are present and (b) fruit are ripening sufficiently to almost be susceptible to egg laying.  The prospect of losing an important tool in the management of SWD emphasizes the importance of following the label directions of pesticides in all regards, including the limitations for use of Entrust® on individual crops and on entire farms, due to concerns for insecticide resistance prevention.

Diseases: For those fields that have received significant rain or overhead irrigation recently, remember that any moisture will stimulate the release of botrytis spores. Late varieties that are still in the bloom stage should be protected with a fungicide spray.

Leaf diseases, including powdery mildew, leaf spot and leaf scorch, have remained at very low levels this week. Fungicide sprays for gray mold often also provide control of foliar diseases. However, it is important to keep an eye out for symptoms in the field, especially following rain, because infections are likely to occur under warm, wet conditions.

Powdery Mildew

Powdery Mildew, photo by David Handley

Angular Leaf Spot

Bacterial Angular Leaf Spot, Photo by David Handley

Leather rot (Phytopthora cactorum) and Anthracnose fruit rot (Colletotrichum acutatum) have been reported this week on ripening day-neutral strawberries grown on black plastic mulch. Warm weather combined with water puddling on the surface of the mulch can lead to the development and rapid spread of these diseases. Fungicides applied for gray mold are generally not effective for leather rot and may not be very effective for anthracnose. Foliar sprays of Aliette®, Agri-Phos® or Phostrol® are recommended for leather rot, while Cabrio® and Pristine® are most effective for anthracnose.

Birds, specifically cedar waxwings will be moving into fields to start feeding on ripe fruit, if they haven’t already. These birds can destroy many of the early ripening fruit, despite our best efforts to scare them off. Only by keeping a near constant presence in the field and eliminating roosting sites can you reduce the damage. Usually, they are discouraged once the fields start to be regularly harvested and customers are present. Songbirds are protected by law and should not be killed. However, permits may be issued for killing birds by the U.S. Fish and Wildlife Service if they receive a recommendation for such a permit from the Maine Wildlife Services Office (part of the USDA Animal and Plant Health Inspection Service) in Augusta, along with an application from the grower. There is a $50 fee for the application, and it may take over a month for the permit to be processed. However, the permit is good for one year, so if you have problems this season, you may consider applying for a permit this winter, which would allow you an option to kill birds, if necessary, next season. The Wildlife Damage Office has recommendations for managing birds in crops, and also has some control options available through their office. For more information on permits or bird control contact the office in Augusta at 207.629.5181. The office is located in the Capital West Business Center at 79 Leighton Road in Augusta.

Hold the Date!
Highmoor Farm Field Day is on Wednesday, July 22, 2015.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

Highmoor Farm                       Pest Management
P.O. Box 179                             491 College Avenue
Monmouth, ME 04259          Orono, ME 04473
207.933.2100                           1.800.287.0279

Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment. A Member of the University of Maine System.

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.