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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #180802
Title: INSECT INFESTATIONS, INCIDENCE OF VIRAL PLANT DISEASES, AND YIELD OF WINTER WHEAT IN RELATION TO PLANTING DATE IN THE NORTHERN GREAT PLAINS

Author
item Hesler, Louis
item Riedell, Walter
item LANGHAM, MARIE - SOUTH DAKOTA STATE UNIV
item Osborne, Shannon

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2005
Publication Date: 12/1/2005
Citation: Hesler, L.S., Riedell, W.E., Langham, M.A., Osborne, S.L. 2005. Insect infestations, incidence of viral plant diseases, and yield of winter wheat in relation to planting date in the northern Great Plains. Journal of Economic Entomology. 98:2020-2027.

Interpretive Summary: The effects of planting date on infestations by insects and on the incidence of viral plant diseases have not been documented for winter wheat in the northern Great Plains. In our study, winter wheat was planted over three dates (early, middle, and late; generally from late August to late September) to determine the effect on abundance of insect pests, incidence of plant damage, incidence of viral plant disease, and grain yield. The study was conducted simultaneously at two sites in South Dakota over three consecutive cropping seasons for a total of six site years. Cereal aphids were abundant in 3 site years. The bird cherry-oat aphid was the most abundant cereal aphid at the Brookings site, whereas the greenbug predominated at Highmore. Aphid infestations were greater in early versus late planting, and aphid abundance in middle plantings usually did not differ from that in early plantings. Incidence of Barley yellow dwarf virus (BYDV) declined with later planting and was correlated with autumnal abundance of cereal aphids. Incidence of BYDV ranged from 24 to 81% among 1999 plantings, and was less than 8% in other years. Damage to seedling wheat by chewing insects varied for two site-years, with greater incidence in early and middle plantings. Wheat streak mosaic virus, spring infestations of cereal aphids, wheat stem maggot, and grasshoppers were insignificant. Yield at Brookings was inversely related with BYDV incidence but not cereal-aphid abundance, whereas yield at Highmore was inversely related with aphid abundance but not BYDV incidence. Planting on September 20 or later reduced damage from chewing insects, and reduced cereal aphid infestations and resulting BYDV incidence.

Technical Abstract: Planting date effects on arthropod infestation and viral plant disease are undocumented for winter wheat in South Dakota and the northern Great Plains. Winter wheat was planted over three dates (early, middle, and late; generally from late August to late September) to determine the effect on abundance of insect pests, incidence of plant damage, incidence of viral plant disease, and grain yield. The study was conducted simultaneously at two sites in South Dakota over three consecutive cropping seasons for a total of 6 site yr. Cereal aphids (Homoptera: Aphididae) were abundant in 3 site yr. Rhopalosiphum padi (L.) (bird cherry-oat aphid) was the most abundant cereal aphid at the Brookings site, whereas Schizaphis graminum (Rondani) (greenbug) predominated at Highmore. Aphid-days were greater in early versus late plantings. Aphid abundance in middle plantings depended on aphid species and site, but usually did not differ from that in early plantings. Incidence of Barley yellow dwarf virus (BYDV) declined with later planting and was correlated with autumnal abundance of cereal aphids. Incidence of BYDV ranged from 24 to 81% among 1999 plantings, and was less than 8% in other years. Damage to seedling wheat by chewing insects varied for two site-years, with greater incidence in early and middle plantings. Wheat streak mosaic virus, spring infestations of cereal aphids, wheat stem maggot, and grasshoppers were insignificant. Yield at Brookings was negatively correlated with BYDV incidence but not cereal-aphid abundance, whereas yield at Highmore was negatively correlated with aphid abundance but not BYDV incidence. Planting on September 20 or later reduced damage from chewing insects, and reduced cereal aphid infestations and resulting BYDV incidence.