Submitted to: Proceedings, IOBC
Publication Type: Proceedings
Publication Acceptance Date: July 15, 2006
Publication Date: August 1, 2005
Citation: Kindler, D., Elliott, N.C., French, W., Arnold, D. 2005. Seasonal occurrence of aphids and natural enemies in wheat and alternative crops grown in Oklahoma. Proceedings of the International Organization of Biocontrol, August 2-5, 2001, Bozeman, Montana. p. 49. Interpretive Summary: Winter wheat is the most important crop grown in Oklahoma at approximately 6 million acres planted each year. The greenbug and other species of aphid are the most important insect pests of winter wheat in Oklahoma, and improved methods for controlling these pests could reduce economic losses. Biological control by predators and parasitic insects is a cost effective control method because it is essentially free. Biological control of the greenbug and other aphids in winter wheat is sometimes effective, but is inconsistent. This study was done to determine whether alternative crops grown adjacent to wheat could improve biological of the greenbug and other aphids in wheat by serving as breeding grounds for predators and parasites, which could move from the alternative crop into wheat fields. Plantings of winter wheat and 12 other grain and forage crops were studied in Oklahoma to determine the species of aphid and the aphid predators and parasites in them. Grain sorghum, cotton, and winter canola hosted several aphids and predators and parasites of aphids during the summer. Winter canola also harbored aphids and predators and parasites of aphids during autumn, winter, and spring. Alfalfa and some other legumes harbored aphids and natural enemies all year. However, in contrast to cotton, canola, and sorghum, the parasites that attacked aphids in legumes were not the same species that attacked aphids in wheat. The study demonstrated the potential for using alternative crops as breeding grounds for natural enemies of aphid pests of winter wheat, but highlighted the importance of selecting the appropriate crop.
Technical Abstract: We monitored experimental plantings of winter wheat and 12 other grain and forage crops for aphids and aphid natural enemies throughout the growing season of each crop for three years. Sorghum (Sorghum vulgare Prescott), cotton (Gossypium hirsutum L.), and winter canola (Brassica napus L.) hosted aphids and predators and parasitoids of cereal aphids during summer months. Winter canola also harbored aphids and predators and parasitoids cereal aphids during autumn and winter. Legumes harbored aphids and natural enemies nearly the entire year. However, parasitoids that attacked aphids in legumes did not parasitize cereal aphids in winter wheat except for the English grain aphid, Sitobion avenae (F.), which was an uncommon species in winter wheat.