Home lady beetle infestations
Irecently passed my 26th year as a UGA county extension agent. I can still remember my early career years in Bartow County. My first office was at the old historic courthouse in Cartersville. It was fun working there.
In fact, I think two movies were filmed while we were housed at the gold domed courthouse. It was amazing how many people work on a movie crew.
I first was a 4-H agent before moving over to agriculture and natural resources. Ed Hornyak was the county coordinator and ag agent at the time. I remember when the weather would get cooler in the fall, his phone would ring off the hook with people needing help with infestations of lady beetles in the home. It got so bad, my co-workers made a cutout or two of lady beetles and hung over his door as a joke.
Still today, I will get calls from clients having issues with lady beetles. Lady beetles are beneficial insects.
At the same time, they can be become nuisance insects when they try to call your dwelling their winter home for the cold months. The purpose of the article today is to give you tips on how to make your home more lady beetle proof before invasions happen. I will be sharing information from Michael Potter, Ric Bessin and Lee Townsend, University of Kentucky Entomologists.
For starters, I would like to give a little history on lady beetle infestations. The first reported invasions of lady beetles in homes or buildings go back to the early 1990s. That would have been just before I stated working for UGA.
There is one species of lady beetles, Harmonia axyridis, that is the problem with these invasions. Some clients will have problems with hundreds of these beetles that are simply looking for a place to overwinter. This species is native to several Asian countries.
How did this species get to the United States? That is up for debate. Our information states that the first field population was found in Louisiana in 1988, but this species is now in most of the U.S and into Canada. In the 1960s to the 1990s, the USDA did make efforts to establish this species in a number of states to take advantage of the beetle’s ability to control pest insects of apples and pecans. Georgia was one of those states.
There are some scientists that believe the current Asian lady beetle populations are not from the USDA releases but from beetles that came in on a freighter that arrived in New Orleans. Again, there will always be opinions on how this species became established in the U.S.
They can be a very helpful insect in controlling damaging insects. The problem is when cold weather arrives and the beetles start looking for overwintering sites.
Your home may be the overwintering spot selected.
The time to start making your home more beetle proof is now. Lady beetle swarms will normally fly to buildings from September to November. This depends on the location and the weather conditions. You may see the swarms more on sunny days following a period of cooler weather when temperatures return to a least the middle 60s. The swarms will be more in the afternoon.
Studies have shown that this beetle species is more attracted to illuminated surfaces. They will tend to congregate on the southwest sides of structures that receive afternoon sun. Information states that house color or type of construction such as concrete, brick, wood, vinyl siding for example is less of a factor for beetle attraction than surface contrast.
This means that contrasting light-dark features will tend to attract beetles. This could be dark shutters on a light home background or light shutters on a dark background. When the beetles arrive on the structure, they will then start looking for crevices and other places to overwinter. They can find their way to attics and wall cavities. These locations can include cracks around windows and doorframes, behind fascia boards and exterior siding too. A home or structure in need of repair with cracks and openings are most set up for infestations.
The best way to reduce these lady beetles from infesting a structure is to seal cracks and openings. You need to seal cracks around windows, doors, soffits, fascia boards, utility pipes, wires, etc. with caulk or other suitable sealant per the information. The information also states that for large holes, you may have to use cement, urethane foam or copper mesh. You should repair damaged window screens. You can also place screening behind attic vents since these can be easy entry points for lady beetles. You may can take advantage of door sweeps at the base of exterior doors too. It is also suggested that gaps under sliding glass doors can be sealed with foam weather stripping.
Finally, in a future column, we will discuss options if you still end up with a structure invasion of lady beetles.