IPM in Cranberries – An Overview

This is the web/text version of a Powerpoint presentation created by Charles Armstrong, UMaine Extension’s Cranberry Professional, in 2016.

Slide 1 (Title Slide): “Integrated Pest Management in Cranberries: An Overview” by Charles Armstrong, Cranberry Professional, University of Maine Cooperative Extension – 2016

Slide 2: Presentation Outline:

  • What is Integrated Pest Management (IPM)?
  • Some IPM History
  • Core Components of Cranberry IPM
  • Cranberry Weed IPM
  • Cranberry Insect IPM
  • Cranberry Plant Disease IPM

Slide 3: What is Integrated Pest Management?  “Integrated pest management (IPM) is a sound, sensible approach to dealing with pests—insects, plant diseases, weeds, and more—with methods that protect human health and the environment while saving money. IPM is integrated because it brings together, or integrates, a range of biological, organic, cultural, mechanical, and chemical options for pest problems.” – definition from the Northeastern IPM Center https://www.northeastipm.org/ipm-in-action/what-is-ipm/ [as of April, 2020]

Slide 4: Some IPM History: (Primary Source: M. Frazier at Penn State Extension; IPM in the Classroom 1997) http://extension.psu.edu/pests/ipm/schools-childcare/schools/educators/curriculum/contents/shorthistory

  • 1962: Rachel Carson publishes her book Silent Spring, documenting the detrimental effects on the environment—especially on birds—of the indiscriminate use of pesticides, and it brings the issue of pesticide safety to the attention of the public:
    • People start questioning and examining: what are the adverse effects on wildlife, water quality, and human health?
    • DDT is found in milk and food
    • Resistance of pests to pesticides becomes a problem
    • Response to the book eventually results in public policy changes during the 1970s
  • 1970s:
    • Significant research undertaken on the topic of IPM approaches to pest control
    • USDA creates nationwide IPM programs at the Land Grant universities
    • EPA is created and is given jurisdiction over pesticide registration & regulation
    • EPA institutes pesticide education programs in the Land Grant universities (such as UMaine Orono)
    • Maine Pesticide Control Act of 1975 (Title 7, Sections 601–625) gives authority to the Maine Board of Pesticides Control (BPC) to regulate pesticides in Maine (one of two statutes that gives this authority) http://www.maine.gov/dacf/php/pesticides/laws.shtml

“It is the policy of the State to work to find ways to use the minimum amount of pesticides needed to effectively control targeted pests in all areas of application. The agencies of the State involved in the regulation or use of pesticides shall promote the principles and the implementation of integrated pest management and other science-based technology to minimize reliance on pesticides while recognizing that outbreaks of disease, insects and other pests will necessitate fluctuations in pesticide use. These agencies, in cooperation with private interest groups, shall work to educate pesticide users and the general public in the proper use of pesticides and to determine other actions needed to accomplish the state policy.” — as of October, 2016. http://www.maine.gov/dacf/php/pesticides/laws.shtml

Slide 6: Core Components of Cranberry IPM:

  • Pest Monitoring and Correct Pest Identification: Monitoring involves mainly visual monitoring (on hands and knees in some cases) as well as the frequent use of a 12”-diameter sweep net
  • Insect Pest Action Thresholds (AT): Rather than relying on the calendar or one’s intuition to dictate when a spray should be applied, one should check to see what, if anything, is present (once or twice per week during the pest season), and any actions against a given pest should be based on the action threshold (AT) for that pest (given as an average per 25 sweeps with a 12”-diameter net). Past history (lessons learned) with the pest should also be considered in the decision-making process.
  • Weed ID, Priority Determinations and ‘Weed Mapping’: Low or High priority weed designations are based on three factors: 1) its ability to spread, 2) its ability to reduce yield, and 3) its susceptibility to control measures. Making a map of one’s weed locations and density, etc. is also advised.
  • For managing fruit rot (Bloom Stage & the Keeping Quality Forecast): The plant stage (specifically, the percentage of open bloom) is used in the timing of any sprays for managing rot. The Keeping Quality Forecast is a yearly prediction of rot pressure that draws on the fact that there is a strong relationship between certain weather factors (mainly temperature, precipitation, and sunshine hours) and the expected quality of the fruit.
  • Cultural Control Practices: Examples include seasonal and de-trash floods, pruning, sanding, mowing and burning of weeds, etc. Flooding is usually the most effective cultural control practice that cranberry growers can employ, especially against insects.

Slide 7: Cranberry Weed IPM

  • Cranberries are perennials, so most of the weed species are also perennials—plants that live for many years and produce flowers and seeds year after year. [Drawing a “Weed Map” is thus encouraged in order to track these weeds from year to year; is that weed problem getting worse, or declining?]
  • Eradication versus tolerance: In cranberry, weed eradication is considered an unreasonable goal, so the presence of many weed populations is often tolerated – but, all weeds are not created equal! [Some weeds compete with cranberry significantly but many others are really only a nuisance and can therefore be safely tolerated.]

Slide 8: Cranberry Weed IPM Strategies:

  • Early preventative measures (for example, hand-weeding after planting so weeds cannot gain a foothold; adequate planting density, maintaining a low/acidic pH, mowing dikes, etc.)
  • Weed Identification, followed by:
    • Prioritization (Deal first with the weeds known to be most worrisome or most destructive; lowest priority ones can perhaps be tolerated)
    • Weed Mapping (in order to monitor challenging or problem areas and gauge any control efforts from year to year)
  • Pre and post-emergence herbicides (if needed)
  • Cultural Practices (examples include ‘Late Water’ flood, pruning, sanding, mowing and burning of weeds)
  • Biological: no viable choices currently

Slide 9: All weeds are not created equal! Massachusetts developed a priority system in 1995 – Weeds are put into any of four groups based on three factors: ability to spread, ability to reduce yield, and susceptibility to control measures.

  • Priority 1 weeds are considered to pose the greatest threat to cranberry farming (most likely with regards to cranberry yield in particular)!
  • Priority 2 (Serious Weeds)
  • Priority 3 (Weeds of less importance)
  • Priority 4 (Weeds of little concern)

Slide 10: Cranberry Weed Priorities (bad ones) — Except for dodder and ‘some’ asters, these are all perennial plants:
Priority 1 (Very Damaging Weeds):
Dewberries, Dodder, Poison ivy, Sawbrier and Wild bean (groundnut).
Priority 2 (Serious Weeds): Asters, Common sawbrier, Narrow-leaved goldenrod, Upright bramble, Yellow loosestrife (Callisto® herbicide has helped to turn the tide against this weed in Maine).

Slide 11: Picture of Dodder with the following information included with the photo:  Dodder is an especially bad “Priority 1” weed but luckily it has been very rare on our Maine cranberry plantings! The host plant receives no benefit from the dodder and the dodder plant requires a host plant to survive. It is referred to as an “obligate parasitic weed.”

Slide 12: Cranberry Weed Priorities (lower priority ones):
Priority 3 (Weeds of less importance): Black chokeberry, Nutsedge, Leatherleaf (woody, evergreen shrub), Perennial sedges and grasses, Red maple, Rushes (Juncus sp.), Sheep laurel and White clover.
Priority 4 (Weeds of little concern): annual broadleaves such as ragweed and smartweed, annual sedges and grasses, Fireweed, ferns, Hardhack, Horsetail, Joe Pye Weed, Meadow beauty, Meadowsweet, mosses, Pitchfork, Sheep sorrel, Sweet pepper bush and White violet [Year 2020 Update from Charlie: Massachusetts has found that mosses are much more damaging to cranberry yields than previously believed, so they would more likely be considered a Priority 2 weed presently or at least a Priority 3 weed].

Slide 13: 2008 Maine Cranberry Grower Survey Findings (Weeds listed by the growers as the hardest to control, and not surprisingly, also the most abundant from year to year): Yellow loosestrife and goldenrod (Priority 2), clover and small trees (Priority 3), and Priority 4 weeds listed were: Horsetail, cattails, ragweed and grasses (annual grasses are Priority 4, but perennial grasses would be Priority 3).

Photo showing a sample of a hand-drawn weed mapSlide 14: (Photo) Example of a cranberry weed map.

Slide 15: Weed Management Herbicides (Cranberries) — Some of the choices for cranberries as of 2016:
– Pre-emergence:
dichlobenil (Casoron®), dichlobenil (Casoron®), napropamide (Devrinol®), norflurazon(Evital®)
– Post-emergence: glyphosate (for example, RoundUp®), sethoxydim ( Poast®), mesotrione (Callisto®), clethodim (Select Max®), clopyralid (Stinger®) (for clover)

Slide 16: How to Help Avoid Weed Resistance:

  • Pay attention to the Resistance Management Grouping number (assigned based on how the chemical works, or its ‘mode of action’; products with the same number have the same or a very similar mode of action).
    • Callisto [mesotrione]: Group 27 (Pigment inhibitor)
    • Casoron [dichlobenil]: Group 20 (Cell wall biosynthesis inhibitor)
    • Crossbow [2,4-D]: Group 0 (non-bed use only) (Growth regulator; synthetic auxin)
    • Devrinol [napropramide]: Group 15 (Thought to block cell division in gap phases of mitosis)
    • Evital [norflurazon]: Group 12 (Pigment inhibitor) (bleaching)
    • Fusilade [fluazifop-P-butyl]: Group 1 (Thought to be a lipid biosynthesis inhibitor; May be involved in disrupting cell membrane function)
    • Intensity [clethodim]: Group 1 (Lipid biosynthesis inhibitor; may be involved in disrupting cell membrane function)
    • Select Max [clethodim]: Group 1 (Lipid biosynthesis inhibitor; may be involved in disrupting cell membrane function)
    • Poast [sethoxydim]: Group 1 (Lipid biosynthesis inhibitor)
    • Roundup [glyphosate]: Group 9 (Inhibits synthesis of amino acids)
    • Stinger [clopyralid]: Group 4 (Growth regulator; thought to affect cell wall plasticity and nucleic acid synthesis) (synthetic auxin)
  • Avoid repeatedly using compounds that fall within the same chemical group!
  • Good resistance management includes alternating products that have different mode of actions, and/or limiting or reducing the total number of applications per season of the same herbicide or herbicides having the same “Resistance Management Grouping” number.

Slides 17 and 18: Cranberry Insect IPM

  • Correct ID is essential!
  • About 24 insects and 1 mite are known to be of economic importance in cranberry.
  • When scouting/searching for pests, try not to be distracted or alarmed by non-pest insects.
  • Probably the four most threatening/destructive cranberry insect pests in Maine are:
    1. Blackheaded Fireworm (2 to 3 generations per year)
    2. Cranberry Fruitworm (single generation per year)
    3. Cranberry Tipworm (3 to 5 generations per year)
    4. Cranberry Weevil (2 generations per year)
  • Scouting / Looking for pest insects:
    • Visual monitoring on hands and knees (only your hands and eyes for tools)
    • Sweep net sampling (aka “sweeping”) Note: Both sweeping and visual monitoring are important and both should be used!
    • Sweeping (weekly, and at least until bloom):
      • Use a 12”- diameter net (pest capture threshold values are based on this size net)
      • One 180°arc swath with the net (in one direction) = 1 sweep
      • 25 sweeps = 1 sweep set
      • Size of Acreage and Number of Sweep Sets Suggested:
        • 1 – 10 acres (one sweep set per acre)
        • 10 – 20 acres (At least 10 sweep sets total)
        • Greater than 20 acres (one sweep set per every two acres)

Slide 19: Cranberry Insect IPM
for an insect pest should be based on scouting (and comparing counts with action thresholds) but should take into account other factors as well, such as:

  • crop value
  • dollar cost of the action or treatment [the thresholds in cranberry are not economic thresholds but just experience-based levels at which you should be ‘concerned’]
  • effects on pollinators and other beneficials
  • potential water issues (if relevant)
  • weather
  • neighbors
  • chemical resistance management

Slide 20: Cranberry Insect IPM

  • Pheromone Traps (usefulness in Maine is questionable!)
    • Trap captures are not paired with an action threshold level (used for application timing only); [Depending on control product to be used, either the start of significant moth flight, peak trap capture, or end of flight will be the trap information needed.]
    • One trap per 10 acres; place on the upwind side of the bed; change lure every three weeks unless otherwise noted; NOTE: a lot of non-target (non-pest) moths are sometimes drawn to the same lures, and can clutter up or even fill up the trap surface area.
  • Behavioral Control: Mating Disruption (not widely used, so very patchy availability of products, if any!)
  • Cultural Control: primarily floods and sanding (Certain floods are often extremely effective against some of the species of cranberry insects!)

Slides 21, 22, 23: Cranberry Insecticides:

  • Carbamates & Organophosphates (broad spectrum)
    • Include Sevin®, Diazinon®, Orthene® and Lorsban®
    • Include the conventional active ingredients used for many years that are often toxic to bees and natural enemies, and often have high human toxicity
    • Target the nervous system
    • Most are being reduced in usage or phased out
  • Insect Growth Regulators (IGRs) e.g. Rimon®, Confirm®, Intrepid®
    • This group interferes with molting or metamorphosis
    • Confirm® and Intrepid® are caterpillar-specific and have low human toxicity; most effective when applied multiple times and in low gallonage against small caterpillars (may take 7 or more days before they die, but they stop feeding long before they die)
  • Spinosyns (e.g. spinosad, spinetoram) [e.g. Delegate®, Entrust®]
    • Target the nervous system, interfering with the insect’s normal functioning at the synapse, causing paralysis and death
    • Work via contact and ingestion
    • Low non-target impact
  • Neonicotinoids [e.g. Actara®, Assail®, Admire®, and Alias®]
    • Targets the nervous system in a way similar to the natural insecticide, nicotine – causes excitation of the nerves, paralysis and death
    • Have systemic activity in the plant
  • Microbial Disruptors of Midgut Membranes
    • Bacillus thuringiensis (B.t.) products that work as a stomach poison (Bt subspecies Kurstaki, or Bt-k, is toxic only to caterpillars)
    • Must be eaten by the insect to have any effect
    • Applications must be well-timed against small larvae, and be applied in low gallonage
    • Have not been widely adopted in cranberry, largely because other reduced-risk options perform better

Slide 24: List of Cranberry Insecticides (as of 2016) (Visit this page for a more current listing: https://extension.umaine.edu/cranberries/grower-services/cranberry-ipm-guide/)

  • Anthranilic diamides (Group 28) (sustained muscle contraction / paralysis)
    • Altacor® (chlorantraniliprole) – very narrow spectrum of activity; very good fit for IPM; mammalian toxicity (oral): very low (no acute toxicity)
  • Tetronic acid derivatives (Group 23) (lipid synthesis inhibitors)
    • Movento® (spirotetramat) (hoping for 2017) – narrow spectrum of activity; very good fit for IPM; mammalian toxicity (oral): very low (no acute toxicity)
  • Oxadiazines (Group 22) [nervous system] (sodium channel blockers)
    • Avaunt® (indoxacarb) – fairly narrow spectrum of activity; good fit for IPM; mammalian toxicity (oral): moderate
  • Organophosphates (Group 1B) [nervous system] (cholinesterase inhibitors)
    • Orthene® (acephate) – broad spectrum of activity; poor fit for IPM; mammalian toxicity (oral): slight
    • Lorsban® (chlorpyrifos) – broad spectrum of activity; poor fit for IPM; mammalian toxicity (oral): moderate
    • Diazinon® (diazinon) – broad spectrum of activity; poor fit for IPM; mammalian toxicity (oral): slight
    • Imidan® (phosmet) – broad spectrum of activity; poor fit for IPM; mammalian toxicity (oral): moderate
  • Carbamates (Group 1A) [nervous system] (cholinesterase inhibitors)
    • Sevin® (carbaryl) – broad spectrum of activity; poor fit for IPM; mammalian toxicity (oral): slight
  • Neonicotinoids (Group 4A) [nervous system] acetylcholine agonists (mimics) (most are highly toxic to bees)
    • Actara® (thiamethoxam) – narrow spectrum of activity; ok fit for IPM; mammalian toxicity (oral): low
    • Admire® (imidacloprid) – narrow spectrum of activity; ok fit for IPM; mammalian toxicity (oral): moderate
    • Alias® (imidacloprid) – narrow spectrum of activity;; ok fit for IPM; mammalian toxicity (oral): moderate
    • Assail® (acetamiprid) – narrow spectrum of activity; good fit for IPM; mammalian toxicity (oral): very low
    • Belay® (clothianidin) – narrow spectrum of activity; so-so fit for IPM; mammalian toxicity (oral): very low
    • Scorpion® (dinotefuran) – narrow spectrum of activity; medium fit for IPM; mammalian toxicity (oral): low
    • Venom® (dinotefuran) – narrow spectrum of activity; medium fit for IPM; mammalian toxicity (oral): low
  • Insect Growth Regulators (IGRs) (Group 18A) [ecdysone mimics] (Disruptors or mimics of the insect hormone ecdysone, which induces premature molting and metamorphosis)
    • Confirm® (tebufenozide) – very narrow spectrum of activity; good fit for IPM; mammalian toxicity (oral): low
    • Intrepid® (methoxyfenozide) – very narrow spectrum of activity; good fit for IPM; mammalian toxicity (oral): low
  • Insect Growth Regulators (IGRs) (Group 15) [chitin inhibitors]
    • Rimon® (novaluron) – very narrow spectrum of activity; good fit for IPM; mammalian toxicity (oral): low
  • Bacillus thuringiensis (Bt) (Group 11B2)
    • DiPel® (Bt) – very narrow spectrum of activity; good fit for IPM; mammalian toxicity (oral): essentially non-toxic
  • Spinosyns (Group 5) (Naturalytes)
    • Entrust® (spinosad) – very narrow spectrum of activity; good fit for IPM (but toxic to bees when wet); mammalian toxicity (oral): low
    • Delegate® (spinetoram) – very narrow spectrum of activity; good fit for IPM (but toxic to bees when wet); mammalian toxicity (oral): low

Slide 25: Cranberry IPM Disease Management

  • Major Cranberry Diseases: Fruit Rot, Phytophthora Root Rot, Upright & Runner Dieback, Cottonball (Wisconsin & some in the Pacific Northwest), Fairy Ring, and False Blossom Disease (False Blossom was a major problem in the cranberry industry in the early 20th century and it may be making a comeback in Massachusetts and New Jersey)
  • Minor Cranberry Diseases: Protoventuria & Pyrenobotrys leaf spots, Red Leaf Spot, Rosebloom, and Ringspot

photo illustrating the concept of the plant "Disease Triangle" where it takes three basic things to bring about a plant disease: a favorable environment, a virulent pathogen, and a susceptible host plant.Slide 26: Cranberry IPM Disease Management (Photo illustrating the concept of the plant “Disease Triangle” where it takes three basic things to bring about a plant disease: a favorable environment, a virulent pathogen, and a susceptible host plant)

Slide 27: Cranberry IPM Disease Management (Weather factors are key!): Temperature: If a pathogen encounters a favorable temperature at every turn, a serious disease outbreak can occur; Precipitation: drought or excess moisture stresses a cranberry plant and lowers its defenses (drought favors Upright dieback and Fairy ring; wetness favors Phytophthora); Humidity: Fungal pathogens require a film of moisture on plant surfaces for the spores to germinate and enter their host plant; Sunshine: Provides ‘drying power’ and the cranberry plant will be operating at maximum efficiency with full sunshine.

Slides 28 and 29: Cranberry IPM Disease Management
Some Key Fruit Rot Factors:

  • Weather is probably the most important factor that affects fruit rot levels.
  • Several different pathogens capable of causing different kinds of rot (12+ fungal species creating 9+ types of rot)
  • Fruit rot fungal population levels will vary from year to year in any given bog (sometimes some of the species of fungi may not even be present in a given year)
  • Vine density (vines stay wet longer the denser they are)
  • Drainage (poor drainage favors fruit rot infection)
  • High water level in ditches (favorable to rot)
  • For many of the various fruit rot pathogens, even though they infect the flowers, they remain latent until the subsequent berry reaches a certain stage of maturity, at which point they will ‘get busy’ and visible symptoms will appear.
  • Symptoms may not be visible until late in the season; sometimes not until after the berries have been harvested and are being held in storage.
  • Some fungi are solely responsible for rot occurring in the field, while others are solely responsible for rot occurring in storage.

Slide 30: Cranberry IPM Disease Management
Fruit Rot Management:

  • Fungicides (beginning in early bloom)
  • De-trash floods (to remove sources of fungal spores)
  • Trash pile removal after harvest
  • Sanding
  • Vine pruning and proper fertilizer scheduling
  • “Late Water” flood
  • Variety selection (‘Stevens’ variety is very resistant to fruit rot)

Slide 31: Cranberry IPM Disease Management
A few notes on some of the other Diseases:

  • Leaf spot diseases are usually held in check via a normal fruit rot fungicide program.
  • Red Leaf Spot is usually a sign of over-fertilization.
  • Upright Dieback – more common following long periods of either drought or heat stress.
  • False Blossom – causal agent is a phytoplasm (similar to a virus); have to control its vector, i.e. the blunt-nosed leafhopper (seems to be making a comeback in MA and NJ)

Slide 32 (End of presentation): For Further Information: Check out the Maine Cranberry IPM Guide available at https://extension.umaine.edu/cranberries/grower-services/cranberry-ipm-guide/

University of Maine Cooperative Extension Pest Management Unit
17 Godfrey Drive Orono, ME 04473
207.581.3880 • charles.armstrong@maine.edu

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

Accompanying Questions to the Online Workshop: “IPM in Cranberries: An Overview”
by Charles Armstrong, Cranberry Professional / University of Maine Cooperative Extension

Instructions:  You can email the information being asked on this form, as well as your quiz answers (or photos of the completed papers) to Charles Armstrong at charles.armstrong@maine.edu or, alternatively, you can print out this completed page and your quiz answers, and mail to the Umaine Extension Diagnostic and Research Laboratory, c/o Charles Armstrong, 17 Godfrey Drive, Orono, ME 04473.

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Quiz Questions:

  1. True or False: IPM does not take into consideration any organic control options when seeking the solution to a pest problem.
  2. Using what you now know about IPM, which of the following would be the best replacement for the word “Integrated” for describing what IPM is all about:
    • A)  Instant
    • B)  Intelligent
    • C)  Impartial
    • D)  Independent
  3. Which of the following events in the history of IPM did not take place during the 1970s:
    • A)  The USDA creates nationwide IPM programs at the Land Grant universities
    • B)  Maine passes the “Maine Pesticide Control Act of [a certain year]”
    • C)  Rachel Carson publishes Silent Springd.
    • D)  A lot of research is undertaken on the topic of IPM
  4. True or False: The Maine State Policy regarding IPM includes the general public when it comes to educating people on the topic of “the proper use of pesticides.”
  5. True or False: Taking into account your past history with a given pest is something that is encouraged as part of cranberry IPM, rather than putting all of your trust solely in some other component of IPM (such as what your ‘scouting’ results are saying that you should do for a pest, in the case of—for example—an insect pest).
  6. Which of the following statements is true about the core components of cranberry IPM?
    • A)  Weed priority determinations were developed based on five different criteria.
    • B)  Relying solely on your ‘gut feeling’ or the date on the calendar for the timing of a pesticide application is a good IPM philosophy or strategy.
    • C)  Correct pest identification is less important than pest monitoring.
    • D)  The practice of making a “weed map” has little value in a cranberry IPM program.
    • E)  The most effective pest monitoring includes careful close-up “visual monitoring” rather than relying solely on sweep net catches.
  7. True or False: Most of the highest priority weeds in cranberries are annuals rather than perennials.
  8. True or False: Total weed eradication is considered a reasonable goal in cranberry IPM.
  9. Which of the following statements about weeds is true?
    • A)  All weeds are “created equal.”
    • B)  There are four groups of weed ‘priority’ in the priority system that UMass developed in 1995.
    • C)  Weeding by hand is never effective.
    • D)  Maintaining a neutral pH is a great way to reduce one’s weed pressure.
    • E)  “Priority 2” weeds are considered “weeds of little importance.”
  10. True or False: Yellow loosestrife is designated as a “Priority 1” weed.
  11. Which of the following is false regarding dodder?
    • A)  It’s not a perennial weed (it’s an annual).
    • B)  Plants afflicted by dodder receive ‘some’ nitrogen from the dodder vines in exchange for the water and other nutrients that the dodder receives.
    • C)  Dodder is parasitic on other plants.
    • D)  Dodder plants cannot survive if they do not eventually find a host plant to infect.
  12. Which of the following is false?
    • A)  Clopyralid is effective against clover.
    • B)  Sedges and grasses that are perennials fall under a “Priority 3” ranking.
    • C)  Napropamide is the active ingredient in Devrinol®.
    • D)  The “Resistance Management Grouping” number given to the cranberry herbicides is determined based on each herbicide’s mode of action.
    • E)  Callisto® and Stinger® share the same mode of action, for how they work.
  13. True or False:  Annual sedges, annual grasses, and mosses, are all considered to be “weeds of little concern” (or at least used to be, in the past) to cranberries.
  14. True or False: There are at least 24 insect pests that afflict cranberries, but only nine of them are known to be of any economic importance in cranberry.
  15. True or False: Blackheaded fireworm is a very potentially destructive insect pest to cranberries in Maine, and it goes through two and sometimes (potentially) three generations per year.
  16. Which one of the following statements is false?
    • A)  ‘Sweeping’ (with a 12”-diameter net) should be conducted once a week during the growing season, right up until at least the start of bloom.
    • B)  Visual monitoring on your hands and knees can be just as important as ‘sweep net’ sampling, when looking for insect pests.
    • C)  The thresholds used in cranberry IPM are true “economic” thresholds based on many years of research.
    • D)  One arc of 180º (in one direction) with your net, equals “1 sweep”
  17. True or False: In cranberry IPM, there are as many as eight (and perhaps more) factors that should be considered when deciding whether or not a ‘treatment/action’ is prudent or justified.
  18. True or False: Confirm® and Intrepid® are IGR materials that would work well against cranberry weevils.
  19. Which one of the following statements is true?
    • A)  All of the neonicotinoids registered for cranberry have very low bee toxicity.
    • B)  Spinosyns target an insect’s digestive system.
    • C)  IGRs generally are most effective when applied multiple times and in low gallonage against small caterpillars.
    • D)  Organophosphates are ‘soft’ on natural enemies and pollinators.
  20. Which one of the following statements is true?
    • A)  Red Leaf Spot is considered by the industry to be a major cranberry disease.
    • B)  Many of the various fruit rot fungi remain latent or dormant in the plant until the berry reaches a certain stage of maturity.
    • C)  Cottonball is a huge problem in Massachusetts.
    • D)  Precipitation and humidity are the only ‘key’ weather factors that play a role in cranberry plant disease infection.
    • E)  The ‘Disease Triangle’ is made up of three components, and as long as you have at least two of those three components, a cranberry ‘disease’ can be the end result.
    • F)  There are only three species of fungi that are associated with cranberry fruit rot.
    • G)  Having a high water level in your ditches will help protect the crop from fruit rot.
    • H)  ‘Field rot’ and ‘storage rot’ are caused by the same fungus.
    • I)  ‘False Blossom’ disease is caused by a fungus that can be spread by honeybees while they are visiting the flowers.


Answer Sheet for: “IPM in Cranberries: An Overview” University of Maine Cooperative Extension. Instructions:  You can email your quiz answers (if that is an option for you) to Charles Armstrong at charles.armstrong@maine.edu or, alternatively, you can print out this page with your quiz answers indicated, and mail to the Umaine Extension Diagnostic and Research Laboratory, c/o Charles Armstrong, 17 Godfrey Drive, Orono, ME 04473.

YOUR NAME:   _______________________________________

A score of at least 80% correct will earn you one pesticide credit towards your pesticide license.

For ‘true/false’ questions, please write the entire word rather than just “T” or “F” so there is no confusion over which answer you mean.

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