Monday, November 13, 2006

Cotton Seedling Management in a Double-Crop System Following Winter Canola.

G. David Buntin1, Kenneth W. Seebold2, Craig Bednarz3, Dan V. Phillps1, and Paul Raymer4. (1) Univ of Georgia, Dept of Entomology, Griffin, GA 30223, (2) Univ of Kentucky, Dept of Plant Pathology, Lexington, KY 40546, (3) Texas Tech Univ, Plant & Soil Sciences, Box 42122, Lubbock, TX 79409-2122, (4) Univ of Georgia, Griffin Campus, 1109 Experiment St., Griffin, GA 30223-1797

Difficulties in establishing cotton in double-crop systems following winter canola have been observed in the southeastern U.S.  Enhancement of cotton seedling diseases and insects following canola is suspected of reducing cotton stand establishment.  This study examined the efficacy of selected fungicide and insecticide treatments at planting in addition to increased seeding rate and at-planting fertilization in preventing stand losses. Treatments were planted following winter canola and wheat. Cotton seedling stand losses were greater following canola than wheat in untreated seed.  Losses following canola were associated with increased incidence of the fungal pathogen Rhizoctonia solani.  The main insect present was cotton aphid, Aphis gossypii.  An at-planting application of insecticide (aldicarb, phorate, or imidacloprid) did not consistently affect stand establishment. Fungicide treatments had variable effects with only Moncut 70W consistently preventing stand loss. Increasing cotton seed rate by 1.5x and 2.0x also resulted in greatest stand in both years. At-planting starter fertilizer did not affect stand following either canola or wheat.  At planting fungicide treatment and possibly increased seeding rate will be needed to mitigate cotton stand losses following winter canola.