Country
Garden 's Recommendations for
Winter Moth & Gypsy Moth Caterpillar Control
Due to the incredible numbers of winter moth caterpillars, and the fact that the eggs have already been laid last winter along the trunks and branches of trees, complete control of this caterpillar is extremely difficult, if not impossible. It is impractical for the average homeowner to spray any trees over 25-30 ft. tall. Therefore, we recommend you concentrate the sprays on smaller deciduous trees and shrubs, and either hire a professional to spray taller trees, or let nature take its course. With a concerted effort, saving specimen trees, shrubs, and fruit trees is possible. The key is to understand the winter moth life-cycle, apply the proper products at the proper times, and OBSERVE CAREFULLY what is happening in your yard.
Step #1- Late March/Early April- Spray Bonide All-Seasons Spray Oil on tree trunks and branches to kill over-wintering eggs.
Step #2- Late April through May- When caterpillars are visible on your plants, spray with either Thuricide Bt or Fertilome Borer, Bagworm, Leaf Miner Spray (Spinosad) as needed. Both of these insecticides are environmentally friendly, but please do not spray when plants are in full bloom, to protect bees. Thuricide works only for the first two weeks or so that caterpillars are out, but a bottle makes 3 times as many gallons of spray as the Fertilome, so some people will use the Thuricide first, then switch as the caterpillars grow bigger. Or just buy the Fertilome and use it through the whole season.
Gypsy Moth Caterpillars- Mid-May through June- Though gypsy moth caterpillars have been been a serious problem in some areas in recent years, 2007 should not be a bad year for them because the pathogen that has helped control the population thrived in the wet weather we had last June. This pathogen killed most of the caterpillars that were present in 2006, which means there will be far fewer this year. If you do see gypsy mopth caterpillars, you can spray with either the Thuricide Bt (on young caterpillars), or Fertilome Borer, Bagworm, Leafminer Spray (Spinosad) as needed.
Caring for Defoliated Trees and Shrubs- If trees are defoliated by caterpillars, make sure they are watered deeply once a week if Mother Nature doesn't do it for you. Fertilizing these stressed plants is NOT recommended.
October/November- A fairly new product, called Eradicoat, has just completed testing and has been found to keep 98% of female moths from laying eggs on tree branches and trunks in late fall. This is NOT an organic or natural product, but it is a very targeted, controlled application of the pesticide permethrin. That is preferrable, and more effective, than repeatedly spraying trees and shrubs with insecticides. |
