November 30, 2017
You may have noticed that there are some moths flying around your yard. You may think that it is a bit odd that moths would be flying around this late in the year. These moths are the adult stage of that little green and white caterpillar that, come the spring, eats the flowers and the leaves on many of the trees that are in your yard. The caterpillar is called the winter moth caterpillar because its parents are around in late November into early December. It is the winter moth that you are seeing now in your yard.
The adult moths emerge now and the males go looking for the female moths. The female moths climb up onto tree trunks to mate and eventually to lay egg cases. These egg cases will produce the caterpillars come the spring. As the leaves emerge in the spring, the tiny caterpillars will eat the leaves of your trees. These caterpillars also love to eat the flower buds of your blueberry bushes. If you have had a number of years were your blueberry bushes produce few or no blueberries, this caterpillar may be the reason.
The caterpillars feed for about 6 weeks in the spring. They then drop to the ground and spend the rest of the year in the soil as a cocoon. In the later part of month of November, they will emerge as the moths that you are seeing now.
The question always is, “How do I control these moths now before they lay their eggs? “ Some people try to spray the moths with an insecticide. This becomes pretty difficult to do because there are so many moths that it is almost impossible to kill them all. Some people have used tree banding to catch the moths. This consists of putting a band of a sticky material around the trunk of the tree. The sticky material traps the female moths as they climb the trees. If you want to try the banding technique, you do not want to put the sticky material directly onto the trunk of the tree. The sticky material called Tanglefoot can damage the bark. You need to put a tree wrap or some other type of non-porous material around the trunk and then apply the Tanglefoot to the wrap. The only problem with this approach is that after the first few moths get stuck to the Tanglefoot, others can just climb over them. This means that the band needs to be fairly wide in order to be effective. This can be difficult to do on young trees where there are branches lower on the trunk. It is one method that does work at this time of the year.
One method that does work is to spray the trunk of the tree with horticultural oil after the moths have laid their egg cases. The oil is mixed with water and sprayed onto the trunk of the tree. The oil penetrates the egg cases and smothers the eggs. As is the case with most things in life, there is a catch. The oil needs to be applied when the temperature are above 40 degrees. This can be difficult to achieve at this time of the year. However, you can spray the horticultural oil in the spring as long as you do so before the eggs hatch out. The timing in the spring would be before the leaves begin to emerge in the spring.
All of the items I have told you about are available in our store.
Well, that’s all for this week. I’ll talk to you again next week.