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Early-Season Insect Defoliation Influences The Critical Time For Weed Removal In Soybean, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist
Early-Season Insect Defoliation Influences The Critical Time For Weed Removal In Soybean, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist
Department of Agronomy and Horticulture: Faculty Publications
To develop more effective pest-management strategies, it is essential to understand how different pests interact with each other and the crop. Field studies were conducted in 2003 and 2004 at two Nebraska locations to determine the effects of early-season crop defoliation on the critical time for weed removal (CTWR) in narrow-row soybean. Three soybean defoliation levels were selected to simulate 0, 30, and 60% leaf tissue removal by the bean leaf beetle. Weeds were allowed to compete with the crop until V2, V4, V6, R3, and R5 growth stages. There were also season-long weedy and weed-free treatments. Results indicated that …
Simulated Insect Defoliation And Duration Of Weed Interference Affected Soybean Growth, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist
Simulated Insect Defoliation And Duration Of Weed Interference Affected Soybean Growth, Travis C. Gustafson, Stevan Z. Knezevic, Thomas E. Hunt, John L. Lindquist
Department of Agronomy and Horticulture: Faculty Publications
An improved understanding of crop stress from multiple pests is needed for better implementation of integrated pest management (IPM) strategies. Field studies were conducted in 2003 and 2004 at two locations in eastern Nebraska to describe the effects of simulated early-season insect defoliation of soybean and duration of weed interference on soybean growth. Three levels of simulated defoliation (undefoliated, 30, and 60%) and seven durations of weed interference (weedy and weed free; weed removal at V2, V4, V6, R3, and R5) were evaluated in a split-plot design. Defoliation significantly reduced soybean leaf-area index (LAI), total dry matter (TDM), and crop …
Economic Importance Of Managing Spatially Heterogeneous Weed Population, John L. Lindquist, J. Anita Dieleman, David A. Mortensen, Gregg A. Johnson, Dawn Y. Wyse-Pester
Economic Importance Of Managing Spatially Heterogeneous Weed Population, John L. Lindquist, J. Anita Dieleman, David A. Mortensen, Gregg A. Johnson, Dawn Y. Wyse-Pester
Department of Agronomy and Horticulture: Faculty Publications
Three methods of predicting the impact of weed interference on crop yield and expected economic return were compared to evaluate the economic importance of weed spatial heterogeneity. Density of three weed species was obtained using a grid sampling scheme in 11 corn and 11 soybean fields. Crop yield loss was predicted assuming densities were homogeneous, aggregated following a negative binomial with known population mean and k, or aggregated with weed densities spatially mapped. Predicted crop loss was lowest and expected returns highest when spatial location of weed density was utilized to decide whether control was justified. Location-specific weed management resulted …