Friday, May 23, 2014

Readers concur: they are winter moths ballooning

Thank you! The tiny tree destroyers were identified by several of you yesterday as 'winter moths'. The collection of comments or emails are included here.

winter moth going back to ground
winter moth going back to ground "ballooning"
Steve, the tiny leaf destroyers are the Winter Moths! They have been around for at least the past 5 years and come out at the same time the trees start to bud, so before the leaf can grow to full size, they are decimated. It makes me CRAZY! My trees look awful already. 
The thousands of small grey moths that are around during the annual warm stretch in November (always around Thanksgiving) they lay their eggs, and after the first 3 warm days in the spring they hatch, by the millions. And they leave a mess as well, because what goes in, must come out! Ugh, I HATE THEM!
Winter moth caterpillar. Stripped my maple. See Weston Nursery web site or Facebook page for description and treatment option. Very bad this year.
Hi Steve. It seems like a kind of leafroller to me. If I remember correctly, the leaves on trees on Franklin Common (and in many other places in Franklin) had many holes in them last year. They have been attacking my Japanese Maple tree for a few years now.
I believe the worms on the trees turn into the winter moths that have invaded the northeast U.S.…

The best full description I found comes from UMASS Amherst:
It is estimated that winter moth eggs hatch between 20-50 growing degree days (base 50) in Massachusetts. Typically, this can occur any time from late March (during atypically warm springs) into the second or third week in April (cool springs). The tiny (less than 1 mm) caterpillars then spin a small silk strand and become air-buoyant and are carried upwards on air currents into the tree canopy where they then try to “weasel” between the bud scales, bracts, etc. to get into the buds. They do not chew their way in via an entrance hole. If buds are not yet swollen enough for them to gain access, these small larvae will then spin down from the tree on a silken thread and be carried away by the wind, which is a dispersal process known as ballooning. 
This is the stage where high levels of injury to the host plant can occur. The longer that the buds stay swollen but unopened, there is a greater potential for feeding injury. Winter moths will enter both leaf and flower buds. For blueberry growers, this is the most critical stage of winter moth activity. If flower buds sustain heavy feeding, there will be no flowers and thus no fruit. There are no known controls for winter moth in this life stage.

You can read the full and complete article here

Here is the Weston Nursery link mentioned above

It is likely that what I have been showing as maple blight has indeed been the increasing influences of the winter moth.

winter moth damage on a red maple
winter moth damage on a red maple
The UMASS Amherst article outlines the treatment options for the various stages. As these caterpillars are already out, it seems the best thing to do now it to wrap the trees with a band to prevent them from climbing up.

Thanks for all the feedback, the sharing of knowledge like this is a great example of what I try to do. There is more power together than alone!

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