The Compound Stresses of Tobacco Thrips (Frankliniella fusca) and Reniform Nematodes (Rotylenchulus reniformis) on Cotton Yield

Tobacco thrips, Frankliniella fusca (Hinds), and reniform nematode, Rotylenchulus reniformis Linford & Oliveira, are important pests of cotton production systems not only because of seedling susceptibility to early season damage, but also the potential of delayed maturity and stunted growth which can result in lower yields. Field studies were conducted in 2015 in Hamilton, MS to evaluate the influence of tillage, seed treatment, and nematicide for the control of tobacco thrips and reniform nematodes. A randomized complete block design with a split-split plot arrangement was used. Treatments consisted of two levels of tillage, (conservational and conventional tillage); six levels of seed treatments or in-furrow applications, (imidacloprid plus thiodicarb, imidacloprid, thiamethoxam plus abamectin, thiamethoxam, aceptate plus terbufos, and an untreated control); and two levels of nematicide, (no nematicide and 1, 3- dichloropropene). Analysis of variance was conducted using the GLIMMIX procedure of SAS 9.4 and p-values that where less than 0.05 were considered significant. There was no significant three way interaction between nematicide treatment, tillage system, and seed treatment on nematode control, thrips control, or damage due to thrips. There was an interaction between seed treatment and tillage on the amount of thrips damage sustained  where conventionally tilled treatments had an overall increase in thrips damage as compared to conservationally tilled treatments, and acephate plus terbufos provided the greatest control against thrips damage compared to other seed treatments. Furthermore, there was a main effect of seed treatment on thrips populations in which acephate plus terbufos provided the greatest population control. Conversely, there were no effects of tillage method, seed treatment, nematicide application, or interactions thereof on nematode population control. There was no interaction between nematicide application and tillage system, or seed treatment, nor was there a main effect of nematicide application on thrips control, damage due to thrips, or nematode population.