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SUNFLOWER: Helianthus annuus L. Insecticide Efficacy against Grasshopper NYMPHs on Sunflower Trial A, 2003 Twostriped grasshopper: Melanoplus bivittatus (Say) Migratory grasshopper: Melanoplus sanguinipes (Fabricius) Registered and experimental insecticides were evaluated for their efficacy at controlling nymph stage grasshoppers and protecting sunflower seedlings. A field in north central North Dakota near Westhope, ND had pretreatment counts of 15 nymph (2-4 instars) grasshoppers/yd2 with the majority being twostriped grasshoppers. Plots were 10 ft wide by 30 ft long. A RCB experimental design with four replicates was used. Insecticides were applied at V2-3 stage on 13 June using a handheld CO2 boom sprayer at 40 PSI, and 10 GPA and fitted with XR 8001 nozzles. Ten seedlings were assessed per plot for the percent defoliation at 4, 7, and 14 DAT. Variables were subjected to ANOVA and means compared using Fisher’s PLSD at the 5% significance level. All of the insecticide treatments had significantly lower percent defoliation than the untreated check at 4, 7 and 14 DAT. There were no significant differences between the different insecticide treatments indicating that all treatments controlled grasshoppers. At 14 DAT, the defoliation increased slightly as grasshoppers continued to move into plots to feed and as insecticide residue was diminished.
Part II. Materials Tested for Arthropod Management INSECTICIDE EFFICACY AGAINST GRASSHOPPER NYMPHS ON SUNFLOWER TRIAL A, 2003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Last Updated:
Tuesday, July 05, 2005 10:26:36 AM
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