Recently we took a trip to Flathead Lake, Montana to visit friends. While there, we experienced an influx of large (almost 3/4”), nasty-looking bugs that descended upon us, literally, every afternoon. There were dozens on the deck, the railings, and any other surface available. Although they looked dead in the morning, they weren’t. As soon as the day warmed, these large critters were again crawling all over everything and flying at our heads.
At first, I feared they were blood-sucking conenoses (yes, there really are such things), which can spread disease. After more research, I was relieved to find they were merely leaffooted bugs, also called the Western conifer seed bug.
Most years the populations of leaffooted bugs are negligible, but this year, at least in Montana, there was a heavy outbreak, probably due to the mild winter.
Leaffooted bugs get their name from the leaf-like flaps on their hind legs. They have piercing-sucking mouthparts that extend half the length of their bodies. The Montana version feeds on the seeds of various conifer trees. Those in other parts of the West also eat fruits, vegetables, leaves, and other plant parts. To insert their mouthpart into a seed, they excrete a digestive enzyme, which liquefies part of the seed into a pulp allowing them to suck out that material.
All these adult bugs are now looking for a warm overwintering site where they will become semidormant, emerging again in the spring. At this time of year, they are attracted to the warmth of the deck, railings, tables and even the sides of cars. They may invade homes trying to find a warm spot. We kept finding them in our RV all the way home.
When high population outbreaks are noticed in the fall, one way to reduce future populations is to remove overwintering sites such as woodpiles. Another method is to mow or eliminate weed hosts, which supply food during winter and spring. An additional way is to hand-pick (yuck!) and crush the bugs, or to brush them off plants and other surfaces into soapy water. Wear gloves because these pests are related to stink bugs, and you don’t want their smell on your hands. Insecticides are not labeled for leaffooted bug control.
For information, visit www.ipm.ucanr.edu/PMG/PESTNOTES/pn74168.html
JoAnne Skelly is Associate Professor & Extension Educator Emerita at the University of Nevada Cooperative Extension. Email skellyj@unr.edu
