Massachusetts IPM Berry Blast
April 15, 2015
Winter Moth Update
Heather Faubert, URI Extension (w/ additional MA data from S. Schloemann)
We may see winter moth eggs hatching at the end of this week. Using The Weather Channel growing degree days (GDD)calculator and their weather predictions, it looks like we will reach 114 GDD, base 40 at the end of this week. This is assuming 114 GDD is a good target number for winter moth eggs hatching and assuming weather predictions are accurate.
Here are when some towns reach 114 GDD or predicted to exceed 114 GDD the next day.
4/16/15 Bristol 108 GDD
4/16/15 Cumberland 107 GDD
4/16/15 Greenville 107 GDD
4/18/15 Kingston 112 GDD
4/20/15 Little Compton 113 GDD
4/20/15 Middletown 113 GDD
4/17/15 North Kingstown 114 GDD
4/19/15 Westerly 113 GDD
4/19/15 Barnstable 110 GDD
4/16/15 East Bridgewater 111 GDD
4/16/15 Franklin 110 GDD
4/17/15 Hanson 109 GDD
4/16/15 Waltham 100 GDD
4/16/15 Westport 106 GDD
You can check look up GDD at your zipcode at: http://www.yourweekendview.com/outlook/agriculture/growing-degree-days/
Enter your zipcode Select base temperature 40 Select start date - use March 1st Select end date - use yesterday's date to see what GDD we are up to, or put in a future date to see what is predicted. Click on Calculate
We will continue to monitor for eggs turning from orange to blue and then hatching at 5 locations. Eggs turn blue a couple of days before hatching. No monitored eggs have turned blue yet.
If you are planning to spray oil to help control winter moth eggs, this is a good week to apply oil since we are close to eggs hatching and night time temperatures are predicted to stay above freezing. Dormant oil applications can suffocate eggs before they hatch. Dormant oil can also be mixed with most insecticides.
I still think it's a good idea to wait to spray an insecticide until eggs begin to turn blue. Most insecticides will control winter moth caterpillars if applied right before eggs hatch and caterpillars move inside buds. Bt insecticides (Bacillis thuringiensis) such as Dipel will not control winter moth caterpillars when they first hatch but is effective once buds open.
Archived IPM Berry Blasts are available at the UMass Extension Fruitadvisor website.
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