Growth and survival of early-instar grasshoppers on selected perennial grasses, with observations on plant constituents which may influence performance.

C.F. Hinks and O.Olfert

Objectives:
To develop management methods for grasshoppers with a minimum dependence on man-made chemicals; to examine effects of perennial grasses on young grasshoppers and to identify species that may be used in roadsides and headlands to reduce grasshopper potential.

Status Report:
Complete

Summary:
Newly hatched grasshoppers were fed a diet of one specific type of grass, and their survival and weights after 5 days were recorded. Grasshoppers did less well on big bluestem, little bluestem, blue grama, smooth brome, or sheep's fescue than on oat or wheat. Most extreme were the results with blue grama. More than 70% of the grasshoppers fed blue grama died. Those that survived on blue grama weighed less than half what those that were fed wheat weighed. Reduced grasshopper performance may have been due to secondary chemicals in the plants, or to a lower nutrient availability in the leaves. Grasshoppers often lay their eggs in areas such as roadsides and field margins. In these locations, sites near perennial grasses are preferred. Grasses that reduce grasshopper performance can slow grasshopper movement into adjacent crops, and reduce the number of grasshoppers in following years. Preserving or seeding grasses such as blue grama, that attract grasshoppers yet slow their growth, could contribute to grasshopper decline.


Impact:
Currently, costs of grasshopper damage for organic producers and of grasshopper controls for conventional producers, are in the millions of dollars. Use of appropriate perennial grasses in roadways can contribute to grasshopper decline without economically and environmentally costly chemicals.


Research Establishment:
Saskatoon Research Station, Agriculture and Agri-Food Canada

Funding Sources:
Agriculture and Agri-Food Canada; Western Canada Grains Research Foundation

Researchers and Contact Information:
O.Olfert, Saskatoon Research Station, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, Saskatchewan S7N 0X2, Canada. [C.F. Hinks, retired]

Source:
Journal of Orthoptera Research 1999. 8: 237-242.