Rangeland-Grasshopper

Many species, including:

Clearwinged grasshopper (Camnula pellucida)
Lesser migratory grasshopper (Melanopus sanguinipes)
Redlegged grasshopper (Melanoplus femurrubrum)
Twostriped grasshopper (Melanoplus bivittatus)

Pest description and crop damage More than 400 grasshopper species live in the western states, but only 10 to 12 typically cause economic damage. Eggs may be deposited in pastures, field margins, undisturbed areas, or in field stubble, and densities may exceed 1,000/sq ft. Immature and adult insects feed in rangeland, pastures, and crop fields. Damage is severe during outbreaks, with the potential for migratory swarms that may invade nearby crops.

Management-biological control

  • Nosema locustae (NOLO Bait Biological Insecticide)-Apply early in the season, as the over-wintering grasshoppers emerge. Two to three weeks may be required for initial effect. Broadcast 1-2 lb/acre around the entire infested area, as well as outlying areas such as drying grasses and fields. Heavy infestations may require repeated applications. OMRI-listed for organic use.

Management-chemical control

University of Wyoming website highlighting Ground-Applied Reduced Agent Area Treatment (RAAT) Strategies may help in developing a strategy for grasshopper control. URL http://www.uwyo.edu/entomology/grasshoppers/atvraats.htm or contact Alexandre Latchininsky at 307-766-2298.

  • beta-cyfluthrin (Baythroid XL) at 0.013 to 0.015 lb ai/a. PHI 0 days for grazing or 7 days for hay. REI 12 hr. Do not exceed 0.089 lb ai/a per cutting.
  • bifenthrin (Brigade 2EC) at 0.1 lb ai/a. Do not exceed 0.2 lb ai/a per season. Retreatment interval: 30 days. REI 12 hr.
  • carbaryl (Carbaryl 4L) at 0.5 lb ai/a. PHI 0 days. Reduced Agent and Area Treatment (RAAT) is required. Do not exceed 1 lb ai/a per crop. REI 12 hr.
  • lambda-cyhalothrin (Warrior with Zeon Technolgy, Lambda-Cy) at 0.02 to 0.03 lb ai/a. PHI 0 days for grazing or forage harvest, 7 days if cut for hay. REI 24 hr. Max 0.03 lb ai/a per cutting, 0.09 lb ai/a per season. Do not re-apply sooner than 30 days after last application if a hay crop is not taken.
  • malathion ULV at 0.62 lb to 0.9 lb ai/a. PHI 0 days. REI 12 hr. Apply by air when hatch is complete. Do not apply if rain is imminent. Most effective when air is above 70°F.
  • malathion (Malathion 8 EC) at 1 to 1.25 lb ai/a. PHI 1 day. REI 12 hr.
  • zeta-cypermethrin (Mustang Max) at 0.0175 to 0.025 lb ai/a. PHI 0 days forage or graze. 7 days for straw. Max 0.025 lb ai/a per cutting. Retreatment interval 7 days for forage or graze, 17 days for straw. Do not apply more than 0.01 lb ai/a per season for hay crops, nor more than 0.0125 lb ai/a per season for forage or straw.