Refinement and validation of soybean looper (Chrysodeixis includens) (Walker) thresholds in Mississippi soybeans (Glycine max (L.) Merr.)
Item TypeGraduate Thesis
Catchot, Angus L.
Musser, Fred R.
Irby, Jon Trenton
Experiments were conducted to refine and validate the soybean looper, Chrysodeixis includens (Walker) threshold in Mississippi soybeans, Glycine max. (L.) Merr. Equivalencies between sweep net and drop cloth sampling methods were evaluated, overall the sweep net was more effective at capturing soybean looper larvae greater than third instar and larvae less than or equal to third instar when compared to the drop cloth method. Feeding studies were conducted to determine the feeding rates of each instar, results showed that fifth instar larvae consume the greatest amount of leaf tissue, and larvae greater than or equal to third instar consume more leaf tissue than larvae less than third instar. Observed and expected/predicted defoliation rates were calculated. Observed defoliation was lower than predicted defoliation possibly due to field environmental conditions. Using data in combination with published data from other studies, three prediction models were created for the R3, R5, and R6 growth stage.