There are a couple of things you can do as a homeowner to help your trees withstand the attack of gypsy moth caterpillars. Without having to spray chemicals. Over the next couple of weeks these little guys are going to get big and they are going to eat a ton of foliage. Lowering the numbers that are on you tree is a great way to help! Use burlap to create a "skirt" around the base of the tree to provide shade for the caterpillars during the day. Ideally check the skirt everyday between 1-3 pm. Remove any caterpillars you find and destroy them. You can squash them or drown them in a bucket of soapy or bleach water. Wear gloves, the hairs on the caterpillars may cause some irritation to your skin.
After the caterpillars pupate and turn into moths they no longer feed on the trees. They have one thing on their mind and that is mating!!! The female moths (white) do not fly they stay in the general area that they hatched from. The males (light brown) do fly and can be lured into a trap using female pheromones, once inside they can not get back out. This will lower the number of pest flying around your property as well help to control the numbers for next years brood.
Another way you can help your tree is to simply water it. Trees need water... who knew?! With our increasingly short winters, combined with extremely hot summers, our trees are struggling. Giving them a drink every couple of days can do wonders for the health of a mature tree. A healthy tree can withstand being defoliated by the caterpillars over a couple of seasons and hopefully pull through. When watering a tree it should be a slow drip process, out around the drip line (where the tips of the branches are). Do not water the trunk as this can lead to bacteria and mold build up at the base and cause root rot. You want to see that water seep deep into he ground. Watering your tree once a week for an hour or two will really help. Gypsy moths outbreaks go in cycles of 7-10 years and last anywhere from 1-3 years so if we make it though this year hopefully we are on the tail end of it!