Spongy Moths…..why are they destructive?
Spongy Moth
The spongy moth, (Lymantria dispar), formerly known as the “gypsy moth,” continues to spread throughout North America, threatening deciduous trees and impacting humans. Efforts to reduce its impact and spread represent one of the largest and most successful federal and state agency integrated pest management programs against a forest pest.
Frequently asked questions
Yes we do. You can survey your woodlot or forest to determine the likelihood spongy moth defoliation for the next growing season. This can be done when egg masses are present, approximately August through April. The surveys typically take 20 minutes to 1 hour to complete, depending on population numbers.
Egg masses are light brown in color and appear as fuzzy or spongy patches on tree trunks, branches, firewood, or in a sheltered spot, even on lawn furniture. Each egg mass contains 600-700 eggs.
Go to this link for more info
https://extension.psu.edu/guide-to-gypsy-moth-egg-mass-surveying
When populations are low or when you have just a few trees you want to protect, spongy moth caterpillars and adults can be killed by squishing them. Egg masses can be destroyed by scraping them off trees or other structures and dropping them in a container of detergent. Another control tactic is wrapping burlap around the trunks of trees where spongy moth larvae can hide during the day. The larvae hiding under the burlap are then scraped into a can of soapy water, killing them.
Microbial insecticides are biopesticides made from naturally occurring bacteria, viruses, fungi, or protozoans that can be targeted to a specific pest. The most common of these is Bacillus thuringiensis (Bt), which occurs naturally in soil and on plants. The Bt subspecies kurstaki (Btk) is the most appropriate to use for LDD control.
Btk works best on young caterpillars, which become more resistant to treatment as they mature. When Btk is eaten, the caterpillar becomes paralyzed, stops feeding, and dies of starvation. Btk is harmless to people, animals, and plants, but does affect other young moth and butterfly larvae. Proper application will help limit exposure to non-LDD larvae.
Spongy moth caterpillar hairs can cause skin irritation, so be careful not to touch them without protection. Skin irritation is a concern during the late spring and early summer when caterpillars are hatching out and growing, but will lessen once caterpillars pupate and turn into moths in late June and early July.
Although oak species are preferred, spongy moth caterpillars feed on hundreds of other tree and shrub species, including:
Apple
Alder
Aspens
Basswood
Birches
Hawthorn
Hemlock
Tamarack (larch)
Pines
Spruces
Willows
Witch hazel