April 16, winter moth update

April 16, 2015

Winter moth egg watchers in Warwick saw several blue winter moth eggs this morning. In Kingston today I found one blue egg. Winter moth eggs turn blue a couple of days before hatching. I think right after tomorrow’s rain is a good time to apply an insecticide to control caterpillars. In some colder areas, such as Little Compton, it is probably better to wait a few more days. The forecast for Saturday is 70, so I expect many eggs will hatch then. The plan is to apply the insecticide right before eggs hatch so caterpillars are killed before they enter buds and begin feeding.

Looking at the Weather Channel growing degree day calculator for April 15:

4/15/15                Bristol                                   120 GDD               02809
4/15/15                Cumberland                       102 GDD               02864
4/15/15                Greenville                           102 GDD               02828
4/15/15                Kingston                              108 GDD               02881
4/15/15                Little Compton                  86 GDD                 02837
4/15/15                Middletown                       86 GDD                 02842
4/15/15                North Kingstown              108 GDD               02852
4/15/15                Warwick                               120 GDD               02889
4/19/15                Westerly                              90 GDD                 02891


Adding a dormant oil to your insecticide spray may be beneficial. Be sure to spray all branch and trunk surfaces.