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1	Evaluation of Management Strategies for the Headworm Complex in Grain Sorghum Dobbins, Christopher Scott 07 May 2016 (has links) During 2013 and 2014, studies were conducted to determine the effects of Helicoverpa zea and Spodoptera frugiperda on both damage and yield of Sorghum bicolor. Results from damage ratings suggest that the amount of damage per single larva decreases as population density increases. Also, yield results suggest that one H. zea and one S. frugiperda larva per panicle results in a 3.6 and 4 percent yield loss, respectively. Additionally, a dynamic EIL was determined using crop value along with various yield potentials and control costs. Other research studies were conducted to determine the efficacy of diamide and pyrethroid insecticides on headworms when applied at midge timing for different locations and planting dates. Results suggest that diamides provide longer and better control of headworms than do pyrethroids. However, applying diamides as a preventative application at midge timing may not be economically feasible when grain prices are low. grain sorghum Sorghum bicolor yield economic injury level economic threshold Helicoverpa zea corn earworm Spodoptera frugiperda fall armyworm Nola sorghiella sorghum webworm headworm complex diamide insecticides