The kudzu bug is a traveler and now calls much of the Southeast home, from the Carolinas to Alabama. And soybean growers need to have eyes on their fields in 2013 to keep tabs on this invasive wonderer, especially in Tennessee. It can put a hurting on yields fast if not treated early.
The kudzu bug is well established in east-central Tennessee, confirmed in Bledsoe, Bradley, Hamilton, Marion, McMinn, Meigs, Polk, Rhea, Sequatchie, Monroe, Loudon, Blount, Roane and Knox counties. "A few soybean fields in this part of the state were treated for this pest. It's only a matter of time before this insect moves into areas of middle and west Tennessee where more soybean acres are grown," said Scott Stewart, integrated pest management specialist with the University of Tennessee Extension.
"I'll be surprised if kudzu bugs are not found west of the Tennessee River in 2013. By 2014, it will probably be common in almost all soybean-producing areas in Tennessee. The good news … this is a pest we can effectively manage with scouting and the proper use of insecticides," Stewart said.
The invasive species is native to Asia, but it was first discovered in the U.S. a nine-county area in northeast Georgia in 2009. By September 2012, it was in all of Georgia and the Carolinas, most of east Alabama and north Florida, too.
Scout, scout and scout again
Soybean acres will likely be up across the Southeast, with prices holding steady in the mid-to-high teens per bushel, and well worth protecting against damage. The kudzu bug can, if left untreated, knock yields down 20%, and in extreme cases by 60% in some Georgia trials, said Phillip Roberts, soybean and cotton entomologist with the University of Georgia Cooperative Extension.
"In Georgia, if when we observed this pest (kudzu bug) in a county for the first time, the next year we saw populations that were treatable, and you had potential yield lose," Roberts said. "We also, at least in our trials and on the farm, early plated soybeans tended to are at greater risk for economic damage.
Pull the trigger
Kudzu bugs have three host plants, ones they prefer to live and love on, kudzu, wisteria and soybeans. The trick to control in soybeans is to hit each immature, developing stage of each generation. A pyrethroid will do it. Scout June to August, when generations will start leaving kudzu for soybeans.
Apply an insecticide when:
-Sweep–net sampling catches one immature insect per sweep. Samples all areas of the field, including edges and the middle, taking care not to bias sampling along border rows where population build initially.
-As an alternative to sweep-net sampling, visual inspections lower in the canopy will suffice. If immature kudzu bugs are easily and repeatedly found on leaf petioles treatment is likely warranted.
Virtual scouting school
If you want to hone your soybean scouting skills, it's as easy as turning on a computer. The University of Tennessee Institute of Agriculture has partnered with the United Soybean Board and the Tennessee Soybean Promotion Board, using soybean checkoff funds, to create the Virtual Soybean Scout School.
The school consists of four brief videos, each led by UT Extension specialists. Watch them at www.UTCrops.com