Influence of agronomic practices on cotton aphid, Aphis gossypii Glover, densities in Louisiana cotton

摘要

A series of agronomic systems examining the influence of tillage systems (conventional-till, ridge-til], and no-till), winter cover crops (native vegetation, crimson clover, hairy vetch, and wheat), and nitrogen fertilization rates (0, 35, 45, 70, 80, 90, 105, 110, and 140 lb N/acre) on cotton production were evaluated in Northeast Louisiana during 1995 to 1998. The effects of these factors on cotton aphid, Aphis gossypii Glover, densities were determined during the last week of June using a visualrating on 25 plants per plot. Cotton plants with > 10 cotton aphids per plant terminal were considered infested with an active colony. The most important agronomic factor influencing cotton aphid populations appeared to be a reduction in tillage practices. Winter cover crops increased the percentage of aphid infested plants above that of native vegetation in only one year of one test. Nitrogen rates did not directly affect the percentage of aphid infested cotton plants.