Kudzu Bug--A Relatively New Insect Pest of Soybean
According to a recent post entitled Kudzu Bugs in Mississippi Soybeans on the MCS blog site, kudzu bugs are now pretty much established in every Mississippi county. According to the authors (Drs. Angus Catchot, Don Cook, and Jeff Gore), all indications are that the migration from kudzu to soybeans will continue into August.
It is important to remember that kudzu bugs do not feed on pods, but rather on stems and petioles. This can lead to yield loss, but the authors emphasize that it takes large numbers of these insects to cause a yield loss. Since most of the high numbers of these bugs on soybeans occur in field edges, a producer often can limit treatment to field borders.
Most of the information about management and control of this insect pest comes from the southeastern US. This means that Midsouth producers are likely to experience issues regarding kudzu bugs that have not been encountered in that region, especially since Midsouth soybeans are planted much earlier than soybeans in the southeastern US. That is why the MSPB recently funded a project entitled “Kudzu Bug Management in Soybeans” that is being led by MSU Assoc. Professor Dr. Fred Musser in cooperation with the above three scientists with MSU.
For now, MSU guidelines have adopted the Southeastern US threshold of 5 bugs/plant during vegetative stages and 1 nymph/sweep during reproductive stages (nymphs, not adults, are major cause of yield losses). The authors caution that since kudzu bugs do not feed on soybean pods, it will take high numbers to be problematic; e.g., the likelihood of low numbers causing yield loss is negligible. They believe that using the nymph threshold (appearance of nymphs indicates that adult migration is over) shown above will minimize the number of insecticide treatments needed to control this pest to as low as one. This is why proper identification of the life stages of the kudzu bug is important so that nymphs rather than the adults are targeted for control.
Clemson University has published a chart entitled “Controlling Kudzu Bug on Soybean” that should be consulted for recommendations of products and their rates to use when an insecticide application is warranted. According to a chart that is included in the above MCS blog, it appears that insecticide products that contain bifenthrin will provide the best control. According to a post from the University of Arkansas, Discipline, Karate Z, and Orthene provide good control as well.
In Arkansas plots in 2016, a fungal disease (Beauveria bassiana) was observed to be infecting and killing kudzu bugs. This disease has been credited with helping reduce kudzu bug populations.
For details about kudzu bug biology and distribution in the Southeastern US, view the PMN webinar entitled Observations and Biology of Kudzu Bugs and Their Management in Southeastern Soybeans presented by Dr. Jeremy Greene of Clemson University.
A USB publication entitled Kudzu Bug–Current Status and Management in Soybeans can be used as a source of general knowledge about the insect and its impact on soybeans.
Composed by Larry G. Heatherly, July 2016, larryheatherly@bellsouth.net