We have started observing eye-catching populations of kudzu bugs on early-planted soybeans in SC, and similar observations are being made in other states. Earlier this week, I took this photo of soybeans planted on 20 April. We did not see this last year this early on planted soybeans, and we have already started getting calls about this. We did see them on volunteer soybeans last year and this year, so we have seen them early, just not on planted soybeans this early.
They did not show up in planted soybeans last year until a little later in the season. In fact, we were convinced that the initial populations we saw in soybeans last year were the first generation out of kudzu. Things are different this year…everything has happened much earlier.
Well, what do we think needs to be done about this early infestation? Here are two scenarios: spray or wait. You could decide to spray at this level of adults. If you do that and follow that guideline, you might end up spraying every week or two, if the population maintains or grows. Re-infestation can happen very quickly. If you delay in treating, will you lose yield? We do not know at this point…all of the data we collected last year indicated that reproducing populations and nymphs were key to yield loss in soybeans. But that was with an infestation that developed much later than what we are seeing so far this season. We think that these adults are overwintered adults that will not live very long. They are laying eggs on the plants, so we will need to monitor those developing nymphs for survival and treat them accordingly. We are just going to have to learn to live with some level of adults infesting our soybeans…no way around that. You cannot eliminate them from a field and keep them out. If these are overwintered adults, and we think that they are, we can probably let these early infestations go for another week or so and see what happens. Remember, we have basically only had 2011 to study this invasive species in soybeans. It will take time to develop solid threshold guidelines, especially whenconditions are always changing.
Here is our kudzu bug webpage: