The cotton seedling damping-off is a worldwide problem caused by a complex of soil-borne and seed-borne fungi, occurring separately or in combination, and cause pre- or post-emergence damping-off. The main etiological agents causing the damping-off are Rhizoctonia solani Khun, Colletotrichum gossypii South and Colletotrichum gossypii var. cephalosporioides. The aim of this work was to evaluate the effectiveness of many fungicides that have been used on the treatment of cottonseeds to control pathogens associated with seeds and/or presents in the soil. Cottonseeds free of pathogens, inoculated and non-inoculated with Colletotrichum gossypii var. cephalosporioides (Cgc), were treated with tolylfluanid + pencycuron + triadimenol; carboxin + thiram and fluazinam + thiophanate methyl. On the Growing on Test, the non-treated seeds inoculated with Cgc showed a lower level of emergence. The higher level of emergence occurred on non-inoculated seeds treated with tolylfluanid + pencycuron + triadimenol. The most efficient treatment in the control of post-emergence damping-off in substrates containing Rhizoctonia solani, was obtained with the mixture of tolylfluanid + pencycuron + triadimenol, followed by carboxin + thiram. In the field, the higher severity of ramulosis, caused by Cgc, occurred in plants from non-treated seeds inocculated with Cgc. None of the fungicides tested showed phytotoxity to cotton.
Chemical treatment; Gossypium hirsutum; Rhyzoctonia; Colletotrichum
