Cultivar resistance to grasshoppers in temperate cereal crops and grasses: A review.

C.F. Hinks and O.Olfert

Objectives: Consider the potential of grasshopper management through crop cultivar resistance.

Status Report: Complete

Summary: Grasshoppers are the most important insects causing damage to small grain crops in Canada. Periodic outbreaks cost millions of dollars in crop damage and in chemical controls. Cultivar resistance has the potential to reduce grasshopper levels without adding to producers' costs. Cultivars are resistant if they withstand grasshopper feeding, or if grasshoppers do poorly when they eat the cultivar. Measuring cultivar resistance can be time consuming, but measures such as growth and weight of newly hatched grasshoppers after 5 days of feeding give a good indication of the potential resistance of a cultivar.

Cereal resistance may be the result of toughness, surface waxes, secondary chemicals such as gramine or trypsin, or tannins. Grasshoppers feed different amounts on different cultivars of wheat, oats and barley. Grasshoppers are suppressed if they feed on some of these grasses - the grasses are resistant. They are less preferred, they are eaten less, they delay growth and slow the movement of grasshopper nymphs into a field. This results in less crop damage.

Grasshoppers frequently lay eggs in roadsides and field margins. Resistant cultivars in these areas can reduce the survival of the nymphs, and slow their movement into adjacent cropland. Several perennial grasses reduce grasshopper potential. Kochia is both preferred by grasshoppers and detrimental to them.

"The prospects of managing grasshopper populations through crop cultivar resistance are encouraging."
Impact: Currently, costs of grasshopper damage for organic producers and of grasshopper controls for conventional, are in the millions of dollars. Cultivar resistance offers the potential of reducing grasshopper populations without the use of chemicals, and at little or no extra cost to the grower.

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

Funding Sources: Agriculture and Agri-Food Canada

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]

Citation: Journal of Orthoptera Research 1992. 1: 1-9