Friday, March 23, 2012
Those dreaded winter moths!
Yes it is that time of year again – well actually, this year it may be coming early thanks to our unseasonably warm winter and spring. If your oaks, maples, birches, apple, crabapple, cherries, blueberries and many other deciduous trees suffered from being munched last year you may need to take action. Timing is so important.
Right now the eggs of the winter moth are still on the branches and trunks of the trees waiting to hatch. Once they emerge they look for a bud of a host plant that is just about to open and they crawl inside. It has been speculated that this year the emergence of the caterpillar and the bud–break may not coincide leaving the insects hungry.
In some locations in Massachusetts the winter moth eggs could hatch as early as the third week in March but the host trees still have very tight buds. This will prevent the tinycaterpillars from entering them to feed and cause them to starve. But you still need to keep an eye on your trees for damage. There are effective and environmentally-friendly options for you to use. You can spray horticultural oil on the exposed eggs on the bark, or if the caterpillars have moved up to the buds or opening leaves, try dormant oil sprays that contains added insecticide, such as a Spinosad product. The oil is effective against the eggs while the insecticide acts to knock down any newly hatched caterpillars. More than one well-timed application may be necessary.
Although considered a safe product the Spinosad can be harmful to bees so please use carefully and preferably at the end of the day when bees are less active. We must be kind to the bees!