Evaluation of Foliar-Applied Insecticides Against Rice Stink Bug, 2018 Open Access

The rice stink bug is an important late-season pest of rice in southern United States. This pest injures rice by feeding on developing grains at the flowering, grain filling, milk, and dough stages of grain development. This study was conducted to evaluate the efficacy of two foliar applied insecticides against rice stink bugs at the LSU AgCenter H. Rouse Caffey Rice Research Station in Crowley, Louisiana. Seeds of long-grain Clearfield rice variety ‘CL153’ were drill-seeded in small field plots (4.1 by 38 ft, 7 rows at 7-inch spacing) at a seeding rate of 60 lbs/acre on 23 Mar 2018. Field plots were surface irrigated as necessary for stand establishment and nitrogen was applied in the form of urea at 120 lbs N/acre on 16 May 2018. Permanent flood was established the following day (17 May 2018). Prior to insecticide application, presence of rice stink bugs was assessed in each plot using insect sweep nets (15-inch diameter). Foliar applications of two rates of Fastac (AI: alpha-cypermethrin), two rates of Mustang Maxx (AI: zeta-cypermethrin), and an untreated check were made on 13 Jul 2018. The insecticide treatments and the untreated check were assigned to plots following a randomized complete block design with 4 blocks and 1 replicate per block. Insecticide treatments were applied using a CO₂-pressurized backpack sprayer calibrated to deliver 10 gpa at 30 psi. The sprayer is equipped with two Teejet TP11001 nozzles at 19-inch spacing. Densities of rice stink bugs were assessed by recording the total number of nymphs and adults per 10 sweeps of 15-inch diameter sweep net in each plot at 3, 7, and 10 days after treatment (DAT). Stink bug data were analyzed separately for each sampling date using generalized linear mixed model (SAS, PROC GLIMMIX) with insecticide treatment as a fixed effect and block as a random effect. Means were separated using LSD (α = 0.10).

At 3 DAT, plots treated with Fastac at 3.2 oz per acre and Mustang Maxx at 4 oz per acre had significantly fewer stink bugs compared with untreated check (Table 1). There were no significant differences among treatments observed for rice stink bug densities at 7 or 10 DAT. During the experiment, pest densities never reached the threshold of 3 rice stink bugs per 10 sweeps in any of the plots.

This research was partially supported by industry and rice research checkoff funds.