Location: Pest Management Research Unit
Project Number: 5436-22000-016-05
Start Date: Jun 01, 2013
End Date: Dec 31, 2013
Evaluation will consist of a field trial in which replicate plots of 2.5 acres will be separated with 200-foot insecticide treated buffer zones to minimize grasshopper immigration/emigration in the plots. The fungus formulation, an emulsifiable concentrate, will be applied broadcast to the plots; a chemical standard and earlier control treatments will be included, for a total trial size of 57 acres including buffers. Total area treated with the fungus will be 10 acres, the maximum allowed without an Experimental Use Permit from EPA. Materials will be applied in an aqueous spray on 25 foot swaths using All-Terrain Vehicles adapted from herbicide application configurations. Grasshopper populations will be estimated in each plot using replicated "ring counts" just before treatments, and again 7, 14 and 21 days post-treatment. Insects will be collected immediately after sprays and again 3,7 and 14 days later, and incubated in the laboratory to assess prevalence of the fungus in the target population. Vegetation samples taken 0, 1, 2, 4, and 7 days post-treatment from fungus-treated and control plots will be bioassayed with grasshoppers to assess persistence of the fungus post application. Grasshopper body temperatures will be recorded using thermal surrogates connected to data logging devices; the surrogates will be placed in microhabitats and postures typical of the grasshoppers in the test. UV-A and UV-B will be measured during the persistence portion of the trial to understand persistence.