Growth and survival to the second instar of neonate grasshopper nymphs, Melanoplus sanguinipes (F.) fed cultivars ancestral to hard red spring wheat

C.F. Hinks and O.Olfert

Objectives:
Determine if the resistance of "modern" wheats to grasshoppers has changed relative to ancestral cultivars.

Status Report:
Complete

Summary:
Cultivar resistance to grasshoppers has the potential of significantly reducing grasshopper numbers and grasshopper outbreaks. "Under the assumption that pests could be adequately controlled by insecticides, breeders became complacent and interest in cultivar resistance waned." Goals of cereal breeding programs did not include grasshopper resistance.

Thirty-one cultivars introduced from 1883 to 1980 were fed to young grasshoppers. The weights of the grasshoppers were used as an indication of the resistance of the cultivars to the grasshoppers, with low weights indicating greater resistance. Cultivars varied in their ability to support grasshopper weight gain, with the cultivars Selkirk, Park, Rescue and Saunders supporting greater weight gain than the cultivars Garnet, Marquis, and Ladoga.

The authors divided the cultivars into four eras: 1883 - 1904 agricultural settlement; 1910-1928 major expansion of wheat production; 1935-1954 introduction of modern pesticides; 1959-1980 stabilization of wheat production. They found that, on average, cultivars developed in the first two eras, before the introduction of modern pesticides, were more resistant to grasshoppers than those cultivars developed in the latter two eras. The study suggests that grasshopper resistance has lessened while the emphasis of breeding programs was elsewhere. It emphasizes the need to maintain a diverse germplasm.
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. Germplasm with potential grasshopper resistance is well worth maintaining.

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

Funding Sources:
Agriculture and Agri-Food Canada; Canada-Saskatchewan Economic and Regional Development Agreement

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 Agronomic Entomology 1993 10: 171-180

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