These bugs aren’t harmful, but they are real pests
We’ve received numerous calls from Rutherford County residents over the past few weeks asking about the small, white, fuzzy critters flying or floating around in the air. Most callers will usually describe the critter’s appearance and then tell of the sticky stuff found on anything (other plants, decks, sidewalks, cars, etc.) that sits under their hackberry tree for any length of time. Many times they’ll also describe an ugly black coating that forms on the things under their hackberry trees.
The callers are describing an insect known as the Asian woolly hackberry aphid, a pest of hackberry and serviceberry trees. The good news is these bugs don’t cause any real harm to the trees they infest and once the leaves have fallen for the year, they won’t be bothering us. The bad news is they make a big mess and create a lot of aggravation, and we’re stuck with them until the hackberry and serviceberry leaves fall.
The sticky material associated with the aphids is known as frass or honeydew and is the excrement from the aphids. The frass drips or blows onto anything under a tree infested with the aphids. The frass provides a perfect environment for sooty mold to grow, which is the ugly black coating that often forms on things under the infested trees. The sooty mold looks terrible, but doesn’t really cause damage to the plants it grows on. Once the aphid population goes away for the fall and winter, much of the sooty mold will wash and wear off plant foliage due to natural weathering from rainfall. Decks, sidewalks, furniture and such can be pressure washed to remove the sooty mold.
Trying to control the aphids by spraying them on mature trees isn’t often feasible because it is difficult to accurately and thoroughly spray a large tree from the ground. A much simpler and effective control is to treat hackberry and serviceberry trees with a systemic insecticide containing an active ingredient such as imidacloprid each spring when the trees put out new leaves. The insecticide is applied to the soil around the base of the tree and requires no spraying and a single application is all that’s needed for the year. This is something most people are capable of doing and insecticides containing imidacloprid are readily available at garden centers.
Another critter that doesn’t cause any real damage, but is incredibly pesky is the multicolored Asian lady beetle (remember the fall of 2013). These beneficial insects become pests when fall weather conditions trigger their normal swarm to overwintering sites and the overwintering site they choose is your home! Contrary to what some have said about these insects, they are a ladybug or lady beetle and are beneficial because they prey on some damaging insects. Multicolored Asian lady beetles start searching for overwintering sites on the second day when temperatures are greater than 65°F after a dramatic drop in temperature, usually to near freezing. These conditions often occur in our area the second or third week of October. Your home is an excellent overwintering site and anything you can do prior to their fall swarm to deny them access to your home will minimize the number of the little pests that get in.
Caulk and/or seal around potential entry points that may need tightening up. Entry points can include spaces around doors, windows, utility openings, dryer vents, etc. The space around such places may seem small, but it doesn’t take a big hole for a ladybug to pass through.
Another measure to reduce the number of beetles that enter a home is to treat roof lines or soffits and areas of vertical color contrast (such as around shutters) and outside around potential entry points with an insecticide prior to the beetle’s swarm. Insecticide products available to homeowners that contain active ingredients such as bifenthrin, permethrin and cyfluthrin have proven to be effective in reducing the number of beetles that actually enter a home. These products’ effectiveness is approximately three weeks (it can be influenced by rain). If a homeowner decides to use an insecticide to help reduce possible home-invading ladybug numbers, an early October application would be recommended with a follow up in three weeks if the swarm hasn’t occurred. It is not common for large multicolored Asian lady beetle swarms to occur past mid-November. Always read and follow label directions when using any pesticide for any reason. multicolored Asian lady beetles that do get into a home can be removed by vacuuming them with a wet/dry or shop vacuum and dumping them outside.
Contact Mitchell Mote, Rutherford County Extension Agent, at 615-898-7710 or by email at firstname.lastname@example.org.