Here is the newest issue of Massachusetts Berry Notes from the UMass Extension Fruit Team.

Massachusetts IPM Berry Blast

March 16, 2017

Heather Faubert, University of Rhode Island

When winter moth eggs hatch depends on temperature and other factors. I don't expect eggs to hatch until after red maples start blooming and when McIntosh apple buds begin to crack open and expose a little bit of green tissue.
          McIntosh apple green tip            Red Maple bloom

FIGURE 1: Winter moth eggs tend to hatch at McIntosh apple 'green tip' and red maple tree bloom.Tree wrap for Winter Moth

Tree wraps have been set up to monitor eggs in 14 locations in RI, one in CT and by at least two Massachusetts blueberry growers. Tree wraps encouraged female winter moths to deposit eggs below tree wraps back in November and December. Tree wraps have been removed and we found hundreds of eggs to monitor. Winter moth eggs are orange now, but turn blue a couple of days before hatching. Very handy for monitoring egg hatch! I'm asking egg monitors to start watching their eggs March 20th.
FIGURE 2: Wrapped tree

For landscape trees it's not important to control winter moth when eggs start hatching, but for apple, pear and blueberry growers it's very important. Once eggs hatch, winter moth caterpillars wriggle into swollen buds and begin feeding. For apple and pear trees and blueberry bushes, swollen buds are primarily flower buds. Caterpillars crawl inside flower buds and begin feeding. Once caterpillars are inside buds, they are protected from insecticide sprays until close to bloom; and by this time many flowers may have been damaged or destroyed, destroying the crop. Landscape trees, on the other hand, can withstand early winter moth feeding damage. To save landscape trees from being defoliated, insecticides can be applied after trees leaf-out, but while caterpillars are still small and before excessive feeding damage has occurred.

Dormant oil can be applied before eggs hatch, but this may not be very effective if unsprayed trees are nearby or if you cannot get complete coverage  with an oil spray. Winter moth eggs are often located in bark nooks and crannies, so complete oil coverage is very difficult. When applying oil, temperature must be above freezing and remain above freezing for 24 hours after application or plant damage can occur.

Winter Moth eggs w/ lichen
Winter moth caterpillars are pretty easy to kill, provided they are not inside closed buds. Insecticide choices for when caterpillars start to hatch for fruit growers include, but are not limited to, spinosad, Imidan, Sevin, Malathion and synthetic pyrethroids such as Asana. Spinosad product names are Delegate (for commercial growers), Entrust (for organic growers) and Captain Jack's Deadbug Brew (for backyard growers). Adding a dormant oil may be useful for the first spray of any of the listed insecticides.

FIGURE 3: Winter moth eggs are nearly impossible to see without setting up tree wrap in the fall.

Once buds open, B.t. kurstaki products (Bacillus thuringiensis kurstaki) such as DiPel and Biobit work well. For landscape trees, winter moth caterpillars can be controlled once trees leaf out with spinosad (Conserve), B.t. kurstaki (Dipel Pro, Javelin, and others), as well as synthetic pyrethroids such as bifenthrin. B.t. products are a good choice because they kill only caterpillars, but B.t. products break down in sunlight after 3-5 days so may need to be reapplied more frequently.
Archived IPM Berry Blasts are available at the UMass Extension Fruitadvisor website.
Where brand names for chemicals are used, it is for the reader's information.  No endorsement is implied, nor is discrimination intended against products with similar ingredients.  Please consult pesticide product labels for rates, application instructions and safety precautions.  The label is the law.  Users of these products assume all associated risks.
We thank Nourse Farms for their underwriting of this newsletter which allows us to keep subscription rates low.
This work was supported in part by funding provided by USDA-NIFA Extension Implementation Program, Award No. 2014-70006-22579

Our newsletter is presented in Adobe PDF format. To read the newsletter you'll need to download a free utility from Adobe called "Acrobat Reader"
It is available from
Copyright © 2016 UMass Extension, All rights reserved.
Archives at:
Our mailing address is:
Mass Berry Notes, French Hall/UMass, Amherst, MA 01003

This email was sent to <<Email Address>>
why did I get this?    unsubscribe from this list    update subscription preferences
UMass Extension Fruit Team · 210 Bowditch Hall · University of Massachusetts · Amherst, MA 01003 · USA

Email Marketing Powered by Mailchimp