Effect of planting date and maturity group on soybean yield response to injury by the kudzu bug, Megacopta cribraria F

The kudzu bug, Megacopta cribraria F., is an invasive plataspid originating from East Asia. Since its discovery in Georgia in 2009 its distribution has increased to 13 southern and eastern states. In the U.S. kudzu bug is bivoltine and has two developmental hosts, kudzu and soybean. In this study we evaluated the yield response of soybean to kudzu bug feeding injury. The study contained four replicated trials conducted from 2012 and 2013, with four planting dates, consisting of split plots in a randomized complete block design with planting date as the whole plot (planted in Griffin, Tifton, Midville and Athens, GA). Soybeans were planted monthly from April to July, dates consistent with those typical in the region. Maturity group 5 and 7 soybeans were used and a broad spectrum insecticide (lambda cyhalothrin) was applied to randomly selected plots. Egg masses, nymphs, and adults were counted weekly to biweekly until soybeans reached maturity. Insecticide protected plots had consistently higher yields than unprotected plots. The yield response was greatest in April planted soybeans and decreased in later plantings. In April and May plantings maturity group did not affect kudzu bug yield response in most comparisons with the exception of the 2012 Griffin trial. This study indicates that early planted soybeans are at greater risk of yield loss from kudzu bug injury than later planted soybeans for double crop production.