Yes, spring is in the air and kudzu bugs are again on the move.
This article covers 1) what is going on in terms of movement right now and 2) what you can expect in terms of future soybean invasions for May and June.
I am not an urban entomologist and cannot provide homeowner information. This is a great concern when these insects are migrating, but rest assured that the insects will not remain on your structure indefinitely.
These insects never really “over-winter”, but simply rest until conditions warm. In fact, I could find kudzu bugs behind tree bark on the coldest day this winter, hold them in my hand to warm them, and they would begin to crawl around.
All indications that we are going to have more kudzu bugs this year than last year. It’s a numbers game. More insects went into over-wintering than previously and they are more widespread.
You might not have noticed kudzu bug activity this time last year, even though it was warm. There are simply more insects around this year.
I expect this spate of activity to last until their preferred host, kudzu, greens up. Until then, expect to find the insects everywhere.
Remember that the presence of kudzu bugs on a plant (figs, magnolias, grapes, etc.) does not mean they are feeding or reproducing on it.
Kudzu bugs are attracted to tall things colored white. Many reports of the bugs are from t-shirts, pickup trucks and big white houses. The insects are certainly not feeding here.
Early-season soybean invasions
If you are planting full-season beans this April or May, you will want to scout the beans early and often.
We first reported the bugs in commercial April-planted soybean fields during May of 2012.
Do not use an insecticidal seed treatment, as the neonicotinoid class of insecticides are not effective for the insect.
Your best option is to keep an eye on the insects, waiting for the adults to complete the field invasion, and to spray once the nymphs hatch from the egg and begin to develop (link to article with photo of small nymphs).
It might take 6-8 weeks for adults to completely invade the field before you begin to notice nymphs.
The recommended sampling method is the sweep net, with one nymph per sweep being a balance point to spray where you can preserve yield, while minimizing trips with insecticide.
You will be tempted not to wait for this. WARNING. A grower last year treated the adults before the nymphs showed up (in early June), which resulted in a re-treatment when nymphs showed up.
This ended up killing natural enemies so that spider mites began to infest the beans. This then resulted in a third spray. We call this the pesticide treadmill. Once you’re on, it’s hard to get off!