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EFFICACY OF FOLIAR INSECTICIDES AGAINST ADULT WESTERN AND SOUTHERN CORN ROOTWORM IN CORN, 2010

2011; Oxford University Press; Volume: 36; Issue: 1 Linguagem: Inglês

10.4182/amt.2011.f14

2156-2385

Terry A. DeVries, Robert Wright,

Insect-Plant Interactions and Control

A study was conducted at the University of Nebraska's South Central Ag Laboratory near Clay Center, NE to evaluate the effectiveness of foliar-applied insecticides against adult WCR and SCR during 2010.Experimental design was a RCB with 4 replicates.Plot size was 4 rows x 40 ft length (N-S orientation) in 30-inch row spacing.'Pioneer 1173H' and 'DeKalb DKC 52-45' corn hybrids were planted on 01 June at a seeding rate of 30,000 seeds per acre.Corn rootworm egg hatch was first observed on 02 Jun.Pre-treatment (PRE) adult WCR and SCR populations were visually counted on the silks of ten primary corn ears per plot on 30 Jul.Foliar liquid insecticide treatments were applied on 30 Jul following PRE counts.Treatments were broadcast over the plant canopy in a 10 gpa water solution via a 20-inch nozzle spacing @ 30 psi.Corn growth stage was early to mid R1.Post-treatment adult WCR and SCR populations were recorded 3, 7, 14 and 21 DAT (02 Aug, 06 Aug, 13 Aug and 20 Aug) on the same ten primary corn ears per plot as the PRE counts.Percent silk clipping was recorded 7 DAT on the same ten primary corn ears per plot.Ear fill was evaluated on 02 Sept (reps 1 & 3) and 08 Sept (reps 2 &4).The total number of unpollinated kernels per 5 primary ears was recorded for each plot.Data were analyzed by ANOVA with mean separation using differences of least square means (P = 0.05).Adult WCR and SCR populations were present at moderate levels throughout the duration of the study.Foliar-applications of Endigo 2.06 ZC, Warrior II 2.09 CS and Hero 1.24 EC insecticides at R1 growth stage significantly reduced the number of adult WCR and SCR on corn silks 3, 7 and 14 DAT compared to the untreated check (Table 1 & 2).Furthermore, all three foliar treatments significantly reduced clipping 7 DAT compared to the untreated check (Table 3).