Effects of an insect–nematode–fungus pest complex on grain yield and composition of specialty low linolenic acid soybean

• Published in: Crop protection Vol. 42; pp. 210 - 216
• Main Authors: McCarville, Michael T., Kanobe, Charles, O'Neal, Matthew E., MacIntosh, Gustavo C., Tylka, Gregory L.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2012
• Subjects: Aphididae; Aphis; Aphis glycines; cultivars; economic threshold; fatty acid composition; field experimentation; Glycine max; grain yield; Heterodera glycines; Identity preserved crop; insecticides; Integrated pest management; linolenic acid; Nematoda; on-farm research; pathogens; pests; seed yield; soybeans; stem rot; Value added crop; Iowa; Value added crop; Identity preserved crop; Integrated pest management
• ISSN: 0261-2194; 1873-6904
• DOI: 10.1016/j.cropro.2012.05.022

Linolenic acid is a precursor to components in plant defense responses to pests and pathogens. Soybean cultivars with altered seed linolenic acid contents have been developed for improved oil qualities, specifically reduced fatty acid content with increased stability. We examined how three common soybean pests, the soybean cyst nematode (SCN, Heterodera glycines), brown stem rot (BSR) caused by Cadophora gregata and the soybean aphid (SBA; Aphis glycines), affect yield and seed linolenic acid percentage of low linolenic acid cultivars. In a micro-plot field experiment, soybean cultivars with varying concentrations of linolenic acid in the seed (ultra-low or low) and resistance to SCN (susceptible or resistant) were grown at a central Iowa research farm. Plots were kept free of pests (control) or artificially infested with a single pest (SCN, BSR or SBA) or the combination of all three pests (multiple pest). The use of resistant cultivars (SCN and BSR) or an insecticide at an economic threshold (SBA) was analyzed to determine the efficacy of current management recommendations for low linolenic acid soybean production. Seed was collected at the end of the season to measure yield and grain composition. All three pests alone or in combination were capable of reducing yield, but only the three pests in combination were capable of affecting seed linolenic acid percentages, increasing linolenic acid percentages by 11.7% in SCN-susceptible cultivars. For all three pests, current management recommendations (resistant cultivars or economic thresholds) provided protection of both yield and grain composition, indicating no changes in management are necessary for altered linolenic acid soybean cultivars.