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United States Department of Agriculture

Agricultural Research Service

Title: Aphid Infestations, Barley Yellow Dwarf Incidence, Plant Growth and Yield of Winter Wheat in Relation to Planting Date and Seed Treatment

Authors
item Hesler, Louis
item Riedell, Walter
item Langham, Marie - SOUTH DAKOTA STATE UNIV

Submitted to: State University Ag Report
Publication Type: Experiment Station
Publication Acceptance Date: February 1, 2005
Publication Date: March 1, 2005
Citation: Hesler, L.S., Riedell, W.E., Langham, M.A. 2005. Aphid infestations, barley yellow dwarf incidence, plant growth and yield of winter wheat in relation to planting date and seed treatment. Progress Report 2004, Central Crops Research Station, South Dakota State University, Plant Science Department Pamphlet 20. p. 29-31.

Interpretive Summary: Delayed planting of winter wheat and use of insecticidal seed treatments are each effective means for managing cereal aphid infestations and limiting incidence of barley yellow dwarf (BYD) disease in winter wheat in the northern Great Plains. Our objective was to compare cereal-aphid infestations, BYD incidence, and growth and yield of winter wheat across various planting dates of wheat with and without use of insecticide-treated seed. Seed treatment generally did not affect pest levels and growth and yield of winter wheat in the 2003-2004 season, in which pest pressure from cereal aphids and BYD virus was low, but the third planting showed better growth and yield of wheat than other plantings.

Technical Abstract: Delayed planting of winter wheat and use of insecticidal seed treatments are each effective means for managing cereal aphid infestations and limiting incidence of barley yellow dwarf (BYD) disease in winter wheat in the northern Great Plains. Our objective was to compare cereal-aphid infestations, BYD incidence, and growth and yield of winter wheat at various planting dates of wheat with and without use of insecticide-treated seed. Planting occurred Aug. 27, Sep. 8, Sep. 17 and Sep. 29, 2003, and seed in each planting was treated with either Gaucho XT insecticide and Raxil MD fungicide or with only Raxil MD. Cereal aphids were counted on plants about 20 and 40 days after planting in each of the respective plots. BYD incidence was estimated by symptoms visible on plants in late spring. Plant growth was measured as leaf area index just before heading. Yield was derived from hand and machine harvesting. Cereal aphid infestations in fall 2003 and spring 2004 were low (less than 0.3 aphid per 20 tillers) across all plantings and seed treatments, and these low infestations would not have impacted yield directly. Seed treatment had no effect upon leaf area index, grain yield, or yield components (as measured by hand harvest). The 17 September planting date had the greatest leaf area index, individual seed weight, and yield. Combine harvest data revealed that yields and test weights (50.5 bushels per acre and 54.6 pounds per bushel, respectively) did not differ among plantings or by seed treatment. In conclusion, seed treatment generally did not affect pest levels and growth and yield of winter wheat in the 2003-2004 season, in which pest pressure from cereal aphids and BYD virus was low, but the third planting showed better growth and yield of wheat than other plantings.

Last Modified: 9/10/2014
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