AgEBB-MU CAFNR Extension

Green Horizons

Volume 22, Number 1
Winter 2018

Agroforestry

From There to Here- Movement of Insect Pests in Winter

By Sarah Phipps| Missouri Department of Agriculture

The outside is mostly still across the winter landscape. Exceptions include the squirrel who scampers up and across the tree branches, and the winter-resident birds found flittering around bird feeders. No arthropods crawling, flying, swarming, or wriggling of any sort are seen anywhere. Well...unless you count the lady beetle flying around the kitchen, alighting on the cabinet doors, or the garage-dwelling spider residing in the abandoned boot.

Like other animals, insects spend the cold winter months hibernating. Insects take refuge as adults, pupae, larvae, or eggs; staying buried in the soil, nestled in the leaf litter, burrowed within trees, or hunkered down in pretty much any spot that can provide protection from the cold. Some simply overwinter as an egg case attached to a twig or branch, or a myriad of other surfaces that females find suitable for egg laying.

While the insect world seems motionless in the winter landscape, the cold, unfortunately, does not halt the movement of invasive insects. They move unbridled from wooded area to wooded area and household to household; travelling undetected along highway corridors across the state and even across the country. You might ask, in their winter stupor, how are insects able to get around? Invasive insects are remarkable hitchhikers as they move with the items we humans carry with us.

Gypsy moth, a notorious defoliator of oak trees and hundreds of other hosts, is one of these quintessential hitchhikers. Established in the northeastern part of the United States (closest population being Northeast Illinois), gypsy moth are able to travel long distances due to their habit of gluing their egg cases that contain 600-1,000 eggs onto commonly found outdoor objects. The female cannot fly. Instead, she crawls up on lawn furniture, playsets, picnic tables, cars, boat trailers, travel trailers, and any other outdoor item she can locate. As the female moth is laying the eggs, she plucks hairs off her abdomen and mixes it with her eggs creating a light brown colored egg mass that can survive some of the harshest winters. Egg masses have been able to withstand temperatures down to negative 30 degrees Fahrenheit.

During the cold winter months, another hitchhiker that travels far and wide with human assistance are invasive wood boring insects moving in firewood. The insects go unnoticed, as they are moving as eggs or larvae of these pests, which may be hidden on or under the bark or buried deep within the wood.

The most infamous woodborer pest in Missouri at this present time is the Emerald Ash Borer (EAB) which feeds on healthy ash trees. The destructive insect has been confirmed in 42 Missouri counties, as well as the City of St. Louis, and is suspected to be present in several more locations. Other notorious wood borer pests that we are concerned about entering our state are Asian longhorned beetle and walnut twig beetle.

Sadly, with the help of humans, invasive insects can travel hundreds of miles in a single day. Alarmingly, what should take decades of natural expansion for these populations to spread, now easily spreads from region to region overnight. To help avoid the danger these pests pose, people need to help prevent pests from moving into our state by being aware and sharing the knowledge with others.

While several state and federal agencies reach out to campsites, nurseries, wood workers, and other likely pathways, anyone can help the effort to protect our forests. The random conversation with a new neighbor or a friendly camper you just met may pay dividends for generations. You never know, a casual chat with a person from an infested area about the dangers of unwanted hitchhikers may save our forests.

For the gypsy moth, all cars, campers, and any other outdoor household articles that could harbor gypsy moth egg masses should be carefully inspected when an outdoor item is moved from a gypsy moth quarantined area in the northeastern United States. If any are found, remove by scraping and dropping into soapy water. It's too late to prevent EAB from getting into our state, but further infestations from other invasive wood-boring insects can be avoided by purchasing local firewood and not moving untreated wood farther than 50 miles from where it was harvested to prevent long distance movement of pests. Please pass the message along!