INSECTICIDE EFFICACY AGAINST GRASSHOPPER NYMPHS ON WHEAT, 2003

Registered and experimental insecticides were evaluated for their efficacy at controlling nymph stage grasshoppers and protecting flag leaves on wheat. A field in north central ND near Ruthville had pretreatment counts of 45 nymphs (3-6 instar)/yd2 with the majority being twostriped grasshoppers. Plots were 10 ft wide by 30 ft long. A RCBD with four replicates was used. Insecticides were applied at Feekes 10 stage on 27 Jun using a hand-held CO2 boom sprayer at 40 psi, and 10 gpa and fitted with XR 8001 nozzles. Twenty flag leaves were collected from each plot to assess the percent defoliation at pre-evaluation, 7 and 14 DAT. Variables were subjected to ANOVA and means compared using Fisher's PLSD (P ≤ 0.05).