INFLUENCE OF TILLAGE, SEED QUALITY, AND FUNGICIDE SEED TREATMENTS ON COTTON EMERGENCE AND YIELD

Seedling diseases of cotton (Gossypium hirsutum L.) limit production i n the High Plains of Texas. Field studies were conducted from 1992 thr ough 1995 to determine the influence of tillage (conventional or termi nated wheat [Triticum aestivum L.] conservation tillage system), seed quality, and fungicide seed treatments (specific for Rhizoctonia solan i, Pythium spp., and Thielaviopsis basicola) on cotton emergence and l int yield. Seed quality positively affected plant emergence and yield in all years. increases in plant emergence and yield were generally fo und with conventional rather than conservation tillage. Emergence 21 d or later was generally lower for untreated seed or Captan (C) ichloro methylthio-4-cyclohexene-1,2-dicarboximide) treated seed than seed tre atments that included triadimenol (Baytan 30 [B]) a-(1,1-dimethylethyl )-1H-1,2,4-triazole-1-ethanol) in 3 of 4 yr; carboxin-PCNB (Vitavax-PC NB [V]) ,4-oxathiin-3-carboxamide-Pentachloronitrobenzene) in 2 of 3 y r and metalaxyl (Apron 2.66F [A]) (N-(2,6-dimethylphenyl)-N-(methoxyac etyl)alanine methyl ester) + C in one year. Yields were affected by se ed treatments in 3 yr, with B being associated with higher yields ever y year and lower yields associated with chloroneb (Nuflow ND [N]) (1,4 -dichloro-2,5-dimethoxybenzene) + TCMTB (2-(thiocyanomethylthio) benzo thizaole (1992), untreated seed (1994) and C (1995). Plants were infec ted most frequently with R. solani and T. basicola. The most consisten t factor affecting seedling disease was seed quality. Conventional til lage and seed treatments specific for Rhizoctonia and Thielaviopsis im proved seedling emergence and yield most years. Interactions between c hemical seed treatments, seed quality, and tillage systems were incons istent between years and even among different evaluation times in the same year.