Winter Insect Control
During the quiet of winter, insect eggs are waiting to wreak havoc on your trees and shrubs. After they hatch in spring, infestations become much harder to control. That is why prevention is so important! Now is a great time to bundle up, get outside, and check for these destructive pests that are commonly found in yards.
BagWorm
Bagworm is a serious pest, affecting mainly conifers like arborvitae, cedar, juniper, and pine, but they can also feed on deciduous trees and even roses! Larvae will hatch in late May and begin to eat the upper epidermis of leaves and needles, often leaving small holes in the foliage and causing extensive damage.
WHAT TO LOOK FOR NOW:
The bags containing the eggs can be spotted dangling down from twigs/branches of trees during the winter. These bags should be hand-picked and placed inside soapy water or a sealed bag to kill them. Concentrate on areas where you have seen them before, since bagworms usually spread slowly out from a ‘hot spot’, as the females cannot fly.
Spotted Lanterfly
Spotted Lanternfly is an invasive pest that puts plants at risk, and should always be killed when spotted. Keep an eye out for invasive Tree of Heaven (Ailanthus altissima) and remove any you may find on your property. These are the host plants of Spotted Lanternfly, and help them spread. Both nymphs and adults suck sap from trees, causing significant damage.
WHAT TO LOOK FOR NOW:
Keep an eye out for gray, clay-like egg masses on trees. Use All Seasons Horticultural Oil on egg masses or scape them off into bags containing rubbing alcohol to kill them.
Spongy (gypsy) moth
Pest affecting mainly woodland and shade trees. Caterpillars mainly feed from and defoliate oak, white and gray birch, apple, willow, linden, basswood, hawthorn, sweet gum, and aspen, but can also affect other trees if populations are high. Defoliation of these trees can leave them susceptible to diseases that lead to their death.
WHAT TO LOOK FOR NOW:
Scout tree bark, rocks, wood piles, and houses for tan colored egg masses (usually around the size of a quarter). To ensure eggs are destroyed, scrape them off into a can of soapy water or apply All Seasons Horticultural Oil.
All Seasons Horticultural oil & Dormant Spray
Organic option to control pests and disease before they become a problem. Apply to any Fruit Trees, Shade Trees, Ornamentals, Shrubs, and Roses on a winter day when temperatures are above 40 degrees. Coat the entire surface of plants to ensure any overwintering insect eggs are smothered.
Works Cited
Boggs, Joe. ““Bagworm Season” Is Wrapping up but Bags Will Remain.” Osu.edu, 3 Sept. 2022, bygl.osu.edu/node/2050. Accessed 9 Jan. 2026.
“CT Spotted Lanternfly.” CT.gov – Connecticut’s Official State Website, portal.ct.gov/DEEP/Forestry/Forest-Protection/Spotted-Lanternfly.
McNee, Bill. “Oil or Remove Gypsy Moth Egg Masses Now.” Govdelivery.com, 28 Mar. 2017, forestrynews.blogs.govdelivery.com/2017/03/28/oil-or-remove-gypsy-moth-egg-masses-now/. Accessed 9 Jan. 2026.
Shannon, Laughlin. “Bagworm Moth | Home and Garden Education Center.” UConn.edu, 23 Feb. 2022, homegarden.cahnr.uconn.edu/factsheets/bagworm-moth/.
“Spongy Moth | Home and Garden Education Center.” UConn.edu, Aug. 2022, homegarden.cahnr.uconn.edu/factsheets/spongy-moth/.
