Red-winged blackbird damage to sweet corn in relation to infestations of European corn borer (Lepidoptera: Pyralidae)
1989
Straub, R.W.
Occurrence of birds in early-season sweet corn plots having low and high infestations of European corn borer, Ostrinia nubilalis (Hubner), was monitored twice weekly. Four species of birds were recorded throughout the monitoring period, but the red-winged blackbird, Agelauis phoeniceus L., predominated (90.1% of total occurrence). More ears were infested by 0. nubilalis larvae in the untreated (46.3%) than in the treated (6.4%) plot, and accumulated injury to ears by red-winged blackbirds was greatest in the plot with the higher infestation of 0. nubilalis. The results suggested that 0. nubilalis larvae attract red-winged blackbirds, and that control of this insect pest results in decreased damage by birds, Feeding by red-winged blackbirds, regardless of the degree of insect infestation, was not observed until the ears were in the milk stage of development. Length of busk extension above the ear tip had little effect on reducing injury by red-winged blackbirds; approximately 69% of the damage to ears was accomplished as the birds penetrated the husk at the side of the ear to extract larvae. Although 0. nubilalis was the insect most responsible for damage by red-winged blackbirds, two other insect species were associated with, ears that were previously damaged by this avian pest.
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