Update on Current Conditions

winter moth caterpillar

Winter Moth Caterpillar

The sunny, warm weather over the last week or two has accelerated plant growth, with many new spring flowering shrubs coming into bloom. We’re now seeing forsythia in full bloom in some regions. From our perspective, this means one thing: it’s time to protect your trees from gypsy moth and winter moth attack. The best strategy is to target the larvae eggs before they hatch.

Winter moth caterpillars are beginning to hatch and look to be plentiful this year, based on egg counts last fall. Newly-hatched winter moth caterpillars immediately seek out the swelling buds of host plants like oaks, maples, apple, crabapple, birch, and blueberry, and wriggle inside to feed.

By carefully observing these swelling buds to look for the presence of fine silk, we can find out where this pest is hiding. In their current stage, they are extremely tiny pale yellow caterpillars. Treatment can still be applied now before the remaining eggs hatch, but once the caterpillars are within the buds, they are virtually impossible to treat until the buds open and the caterpillars once again are exposed.

Be aware that having five to six caterpillars per bud can result in the death of the bud. The quicker the buds open, the less likelihood of severe damage.

In other news:

  • Adult deer ticks have been very active so far this year. If you’re going to be working in brushy areas, make sure you do thorough tick checks after you come inside. Consider using repellents, shower or bathe after yard work, and wash and dry your clothes to kill off any ticks.
  • Many hydrangea stems and flower buds were killed due to winter weather. In these cases, we’ll need to prune back the dead stems to the live wood. Though it doesn’t look likely right now, if temperatures drop below freezing again, we can expect more damage to flower buds.
  • Because of all the heavy snow and windy conditions over this past winter, many woody trees and shrubs are in need of corrective pruning.
  • Many winter annual weeds (such as cresses) are in full growth right now. It’s important to remove these before they go to seed.

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