Effects of sagebrush removal and legume interseeding on rangeland grasshopper populations (Orthoptera: Acrididae)

Published source details Hewitt G.B. & Onsager J.A. (1988) Effects of sagebrush removal and legume interseeding on rangeland grasshopper populations (Orthoptera: Acrididae). Canadian Entomologist, 120, 753-758.
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This study is summarised as evidence for the following.

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	Use mixed pasture Action Link

Use mixed pasture

A replicated, controlled trial from 1982-1985 at two pasture sites in Montana, USA (Hewitt & Onsager 1988) found that an index of overall grasshopper (Orthoptera) grazing intensity and presence was higher in interseeded pastures (19-2,852 grasshopper days/m²) than control native pasture (7-1,377 days/m²) but annual rates of grasshopper increase were similar between treatments (5.35x vs. 5.92x annual increase). One dominant species, the migratory grasshopper Melanoplus sanguinipes increased more in interseeded plots (29-1,367 estimated cumulative grasshopper days/m²) than controls (23-501 days/m²) from 1983-1985. Grasshoppers caused 10% seedling mortality in one interseeded plot. Forage yield was higher in interseeded (454-1,290 kg/ha total herbaceous yield) than control pastures (240-739 kg/ha). Two pastures (one at each site) were seeded with dryland alfalfa Medicago falcata and cicer milkvetch Astragalus cicer (both at 2.2 kg/ha) in April-May 1982. One was treated with herbicide, the other cut mechanically to control sagebrush Artemesia tridentata (weed). Control pastures had a mix of unsown species. Interseeded pastures were grazed by 10 steers for 48, 40 and 20 days and control pastures by five steers for 90, 60 and 40 days in 1983-1985 respectively. The effects of interseeding and different grazing intensities could not be separated.