UMass Extension Landscape Message #3 - 2015

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RE Winter Moth egg hatch:

"Life Cycle: After mating, the female deposits eggs
loosely in bark crevices, under bark scales, under lichen, or elsewhere.
The adult moths then die and the eggs over- winter. Eggs are
dark-colored at first but turn orange within 3-4 weeks. In late-March or
early-April, just prior to hatching, they turn red and eventually a deep, shiny blue. Eggs hatch when temperatures average around 55 ̊F. It
is believed that egg hatch in Massachusetts occurs when approximately
177-239 GDD above a base of 40˚ F (starting Jan 1) have accumulated,
which is historically during the second week in April but later if
temperatures are atypically colder, depending. This means that egg hatch
occurs just at or right before bud break of most of the host plants.
After hatching, the larvae wriggle between bud scales of newly swelling
buds of such hosts as: maples, oaks, ash, apples, crabapples, blueberry,
cherries, etc. and begin feeding.

This year, models suggest that we will reach egg hatch after April 15, 2014. Pinpointing a date is too risky now, but another alert will be sent out in a soon to update the forecast."

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Claire