Damage by greenbug (Homoptera: Aphididae) to grain sorghum as affected by tillage, surface residues, and canopy
1987
Burton, R.L. | Jones, O.R. | Burd, J.D. | Wicks, G.A. | Krenzer, E.G. Jr
Different cropping systems for grain sorghum were studied at two Texas locations and one Nebraska location to determine effects of tillage practice, cropping systems, crop residues, and plant canopy on greenbug, Schizaphis graminum (Rondani), abundance and crop damage. In each case, reduced tillage or crop residues on the soil surface (or both) resulted in a decreased number of greenbugs and amount of plant injury. In one study, a greenbug-resistant grain sorghum hybrid conventionally tilled was more severely damaged than a susceptible hybrid planted in a no-tillage situation, indicating the negative effect of reduced tillage on greenbug abundance. Influence of reduced tillage on greenbug density occurred on plants in plots as large as 2.8 ha. In one grain sorghum field, a dense canopy of a weedy grass that obscured furrows substantially reduced greenbug infestation. In other fields, independent of surface residues and canopy, greenbug seemed to distinguish between amount of cultivation and preferred plants growing in soil with the greatest amount of disturbance. Apparently, greenbugs respond to background conditions of the host plant associated with tillage operations and seem to be repelled by crop residues, canopy, and the reduced tilled soil surface.
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