No doubt, everyone remembers what a terrible summer 2020 was with the devastating defoliation of our trees caused by gypsy moth caterpillars. They seemed to eat all of our cottage trees, both deciduous and coniferous, as well as our shrubs. After the plague of tent caterpillars of 2018, the ‘ick’ factor has been running high and non-stop around our little piece of paradise on White Lake. Nature runs in cycles, but the cycles of invasive, defoliating species are running back to back within our region … poor trees.
Experts have advised that 2021 may be another bad year. They have issued information and strategies on how to battle this year’s anticipated invasion. It is important because we know how damaging these hungry caterpillars can be and we know too they are pervasive throughout our area.
In the autumn of 2020, not only did the gypsy moths lay masses of eggs on our tree trunks, a goodly number were deposited in our outhouse and woodshed, as well as on the surface of our archery target backboard. The first photo below shows the male in all his splendour. His bushy antennae distract us from this handsome fellow’s evil deeds. The second shows two females at the start of their egg laying. At least the flat surfaces made it fairly easy to scrape away the egg masses with a putty knife.
It takes more concentrated effort to scrape the egg masses from tree trunks. We find the easiest way to destroy the egg masses is to scrape them off with a putty knife and then stomp and grind them with our heavy footwear, but you may wish to scrape them into a bucket of soapy water for a couple of days to kill the eggs. We learned the hard way from our first attempts at scraping off egg masses in the outhouse to wear a disposable face mask as protection from the invisible ‘dust’ that comes from the protective hairs that cover the egg masses. Other ways to deal with them are covered in the White Lake Property Owners Association’s (WLPOA) and Health Canada’s environmental bulletins. Links are provided in the references section at the end of this article.
The ravenous caterpillars that cause so much damage hatch from the egg masses at the cottage in mid-June, but sometimes as early as April to the south of us. They eat foliage and grow through July before pupating. Subsequently, they emerge as adults which mate and lay their eggs in September … and the whole cycle starts over.
Despite being an invasive species, some predators do exist, including the black-billed cuckoo, blue jays, and orioles, all of which eat the caterpillars. At Three Mile Bay, we see blue jays regularly, orioles sometimes in the spring, but rarely the black-billed cuckoo. We were delighted to hear the unique cu-cu-cu of this cuckoo more frequently in 2019. Possibly their numbers grew in response to the tent caterpillar invasion of 2018. We hope cuckoos will be around to help us out in 2021.
We were delighted to learn that chickadees will feed on the egg masses, and chipmunks, skunks, raccoons, and squirrels eat gypsy moth pupae. Nevertheless, we all need to be gypsy moth predators!
We can hardly wait to get back to the cottage in part to continue scraping gypsy moth egg masses out of the outhouse and woodshed. We feel it is important for us to be gypsy moth predators to reduce defoliation of the trees on our as well as our neighbours’ properties, and mitigate the impact of a potential second summer of defoliation by gypsy moth caterpillars.
Additional information can be found in the WLPOA bulletin at: http://www.wlpp.ca/linked/control_of_gypsy_moth_infestation.pdf
and the Government of Canada website:
https://www.canada.ca/en/health-canada/services/pest-control-tips/gypsy-moths.html Copy and past these links into your web browser.