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Vol. 17, No. 8
Article 5 of 10
May 1, 2007
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Potential for Economic Infestations of Black Cutworm Larvae By Wayne Bailey Intensive captures of BCW moths continue to be recorded for several locations in Missouri. Intensive captures of moths indicate heavy moth activity which may result in problems with black cutworm larvae in field corn. At present, the Missouri Black Cutworm Predictive Model is predicting possible damage resulting from this pest during the 2nd to 3rd week of May. Some locations will record multiple intensive captures which indicate the possibility of multiple infestation dates of larvae. Predicted dates of first cutting are updated daily as local weather conditions are incorporated into the model. Intensive trap captures and predicted dates of first cutting by 4th instar black cutworm are listed by locations reporting moth intensive captures: Ray County (Richmond): Intensive capture date, 4/11/2007. Predicted first cutting, 5/15/2007. Barton County (Lamar): Intensive capture date, 4/13/2007. Predicted first cutting, 5/13/2007. Callaway County (Fulton): Intensive capture date, 4/18/2007. Predicted first cutting, 5/20/2007. Audrain County (Mexico): Intensive capture date, 4/2/2007. Predicted first cutting, 5/17/2007. Knox County (Edina): Intensive capture date, 4/25/2007. Predicted first cutting, 5/23/2007. Franklin County (Union): Intensive capture date, 4/20/2007. Predicted first cutting, 5/23/2007. Intensive moth captures do not always result in economic infestations of black cutworm, but do predict a date of first cutting. Scouting activities should occur from first emergence of corn plants and continue through the 5th leaf stage of plant development. If this is not possible, then scouting of fields should begin a minimum of one week prior to the predicted date of cutting. Early damage by black cutworm larvae smaller than 4th instars may be visible as leaf feeding on corn plants. For more information on the black cutworm predictive model and the counties currently monitoring for black cutworm, please visit our Website at: http://ipm.missouri.edu/pestmonitoring/blackcutworm/index.htm. Although the economic threshold for black cutworm varies from state to state, under normal conditions in Missouri treatment is recommended when cutting of corn seedlings reach or exceed 4-6 percent cutting above ground and 2-3 percent cutting below ground. These thresholds are based on the location of the plant growing point at the time of cutting by black cutworm.
Wayne Bailey | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
