The black cutworm Agrotis ipsilon is a sporadic pest of corn. It cuts seedlings at the base of the plant, reducing plant stands by 75-90% in individual fields. Ontario no-till cornfields were monitored during the 2001/2002 growing seasons to investigate the relationship between the presence of weeds and bean crop residues and cutworm damage. Weeds can limit the impact of cutworm infestations, providing an alternate host for the larvae and reducing crop apparency. Crop residue is a favored oviposition site and provides shelter. Fields were monitored from emergence to 6-leaf stage for cutworm damage and developmental stages of larvae present. Corn leaf stages and damage ratings were recorded for 5 transects per field, digital photographs of 3 randomly placed quadrates per transect were collected and analyzed in relation to the damage counts. In the past, weeds could not easily be removed after corn emergence without damaging the crop, and could therefore not be managed to minimize the impact of cutworm infestations. Today, with the new herbicide resistant transgenic corn varieties, this constraint no longer exists. The field observations presented in this poster are part of an ongoing investigation to evaluate the use of this herbicide resistance as a cultural management tool for black cutworm and to determine the effect of alternate host presence during early corn development. The alternate weeed host should reduce the apparency of the crop, as well as providing an alternate food source for the larvae, thereby reducing overall damage to the corn plants.
Species 1: Lepidoptera Noctuidae Agrotis ipsilon (black cutworm, greasy black cutworm)
Keywords: phenology, cultural management
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