{"id":12283,"date":"2025-06-06T14:28:31","date_gmt":"2025-06-06T18:28:31","guid":{"rendered":"https:\/\/extension.umaine.edu\/highmoor\/?p=12283"},"modified":"2025-06-06T14:28:31","modified_gmt":"2025-06-06T18:28:31","slug":"strawberry-ipm-newsletter-no-5-june-6-2025","status":"publish","type":"post","link":"https:\/\/extension.umaine.edu\/highmoor\/2025\/06\/06\/strawberry-ipm-newsletter-no-5-june-6-2025\/","title":{"rendered":"Strawberry IPM Newsletter No. 5 — June 6, 2025"},"content":{"rendered":"

MORE RAIN MAKES INCREASES FUNGAL DISEASE THREAT<\/h3>\n

Fungicide Applications Bloom – Post-Bloom To Control Botrytis, Anthracnose, Powdery Mildew<\/h4>\n
\"Two-spotted<\/a>
Two-spotted Spider Mites; photo by David Handley, UMaine Cooperative Extension (click photo to enlarge)<\/figcaption><\/figure>\n

Situation<\/strong>: A few warm days can make quite a difference! Strawberry growers in southern Maine are starting to see some ripe berries on early varieties and plants grown under row covers. Later varieties are still showing some bloom in central and northern regions of the state. We continue to find adults and nymphs of tarnished plant bugs, and spider mites this week. Continuing damp weather is ideal for the development of fungal diseases, including Botrytis<\/em> gray mold, leather rot and anthracnose. Growers with bloom in their fields should be applying preventive fungicide sprays through petal fall.<\/p>\n

Two-spotted spider mites<\/strong>: Mites were present in most fields we\u2019ve scouted. We recommend that you continue scouting for mites right up to harvest. Once harvest is over and the beds are renovated, you should scout for mites again in the late summer to early fall and be ready to apply a miticide to prevent high overwintering populations from infesting the fields next spring.<\/p>\n

Strawberry bud weevil<\/strong>: Most fields are now beyond full bloom and the susceptible stage for clipper feeding and bud injury. We have found very few clipped buds or weevils this season, but if you still have late varieties coming into bloom susceptible to injury, scouting should continue.<\/p>\n

Tarnished plant bugs: <\/strong>Both adult and nymph stages of tarnished plant bugs are now present in strawberry fields. Populations have been spotty from one location to another and even within a field, so it is well worthwhile to scout your fields for their presence before applying an insecticide. The threshold for plant bug nymphs is four or more flower clusters infested per 30 sampled. Tap flower clusters over a plate or tray to knock nymphs off. Insecticide options for tarnished plant bugs include malathion, Assail\u00ae, Brigade\u00ae, Bifenture\u00ae, Dibrom\u00ae, Danitol\u00ae, Closer\u00ae and PyGanic\u00ae.<\/p>\n

\"Close<\/a>
Strawberry Root Weevil Adult; photo by David Handley, UMaine Cooperative Extension (Click photo to enlarge).<\/figcaption><\/figure>\n

Strawberry root weevil: <\/strong>Strawberry root weevils and Black vine weevils begin to emerge and start feeding on strawberry foliage during the harvest season. Look for notching along the leaf edges and the presence of the black or brown snout beetles. The weevils feed mostly at night and spend the daylight hours at the base of the plants under the mulch. They lay eggs at the base of the crowns during the harvest and post-harvest period. The larvae, or grubs, feed on the strawberry plant roots through the fall, overwinter deep in the soil and start feeding again in the spring, causing plants to weaken and die. Badly infested beds should be plowed up as soon after harvest as possible. Bifenthrin (Brigade\u00ae) can be applied to kill the adults when they emerge and start to feed on the leaves (usually until mid-late July). Applications should be made at night when the insects are active, and the highest rate of the insecticide should be used. Platinum\u00ae can be applied in the fall as a soil drench to control grubs.<\/p>\n

\"Spittlebug<\/a>
Spittlebug, Photo by David Handley, UMaine Cooperative Extension (click photo to enlarge)<\/figcaption><\/figure>\n

Spittlebugs<\/strong>: The first spittlebugs of the season were found this week. The frothy spittle masses appear on the leaf stems (petioles), just below the leaflets. These typically start showing up around bloom. Although these spittlebugs don\u2019t pose a significant threat to the plants, the frothy spittle they cover themselves with creates an annoyance for pickers. Adult spittlebugs are about 1\/4 inch long and bright green when they first emerge but later turn dull yellow or brown. Spittlebugs overwinter as eggs and the nymphs emerge in late May. You should start to scout for spittlebugs when the plants are at about 10% bloom. Randomly inspect five one square foot areas per field every week. Spread the leaves and inspect the leaf bases, leaf stems, and flower stems looking for the white, frothy spittle masses. Spittlebugs tend to be a greater problem in weedy fields. Pesticides currently registered for spittlebug control include Provado\u00ae, Danitol\u00ae and Brigade\u00ae.<\/p>\n

Potato leafhoppers<\/strong>: Keep a lookout for potato leafhoppers. 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 and may look like herbicide damage. 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 Assail\u00ae, malathion, carbaryl or Provado\u00ae.<\/p>\n\n\t\t