|Roof, M - CLEMSON UNIV.|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 21, 2001
Publication Date: N/A
Technical Abstract: Grass cover crops have been reported to lessen the severity of thrips (Frankliniella spp.) in seedling cotton (Gossypium hirustum L.). We conducted this three-year study to determine how cotton grown with conservation tillage responds to N fertilizer rate following different winter cover crops both with and without pesticide protection from early season thrips. Treatments were winter cover crops [fallow, rye (Secale cereale L.), crimson clover (Trifolium incarnatum L.), and rye and clover mixed], N rate (0, 78, and 112 kg N/ha) and aldicarb application rate (0 and 1.12 kg a.i./ha). Aldicarb reduced thrips populations and seedling damage to almost zero each year. In general, thrips populations and damage were uniformly high across cover crop species and N rates when aldicarb was not applied. Thrips damage did not affect lint yield in 1996. In 1997 and 1998, largest yield reductions by thrips damage were at the higher N levels. Cotton lint yield ranged from approximately 300 to 1200 kg/ha in 1996, from 100 to 1100 kg/ha in 1997, and from 200 to 700 kg/ha in 1998. Yield was closely related to the total amount of N (N in the winter cover plus fertilizer N) in all three years of this study.