Field Crops News

Minute Pirate Bug Good Predator of Corn Earworm and European Corn Borer Eggs on Corn

The insidious flower bug, Orius insidiosus, is known to feed on the eggs of both European corn borer and corn earworm on corn. The searching behavior of this predatory bug on reproductive stage field corn was studied. Corn borer eggs were placed on upper or lower surfaces of leaves near the ear or on the ear husk to mimic the range of normal placement of eggs. Orius adults were more likely to find eggs on the leaf surface than on the ear, but were equally likely to find eggs on either the upper or lower surface of leaves. About 75corn earworm eggs were placed on silks, tassels or leaves of each plant. The eggs most frequently fed upon by Orius were those attached to the silks. As predator densities were increased from 1 to 12 Orius per plant, the percentage of eggs killed increased from 24% to 100%. Eggs placed on tassels were rarely fed upon even at 12 Orius per plant, and eggs placed on leaves were only fed upon at the highest predator rate (12 per plant), suggesting that these sites are much less preferred. Orius bugs are highly attracted to corn silks which makes them a good predator of corn earworm eggs, because corn earworm eggs are primarily laid in the silks. Although silks are preferred by Orius, in the absence of prey in the silks, Orius were able to search for and kill European corn borer eggs on both the upper and lower surfaces of leaves. These data suggest that Orius insidiosus is well suited as a predator of corn earworm and European corn borer eggs on reproductive stage field corn.

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