EFFICACY OF FUNGICIDES AND Trichoderma harzianum AGAINST SEED BORN PATHOGENS CAUSING BOLL ROT DISEASE OF COTTON

Abstract

Experiments were conducted on efficacy of fungicides and Trichoderma harzianum against seed born pathogens of cotton. A field experiment was conducted for the prevalence of cotton boll rot disease in Cotton Research Training and Seed Multiplication Farm, Sreepur, Gazipur and laboratory experiments were conducted in the laboratory of Sher-e Bangla Agricultural University, Dhaka, Bangladesh during the period of April 2012 to May 2013. Three cotton varieties CB-9, CB-11 and CB-12 were used in this experiment. Three genera of fungi viz. Colletotrichum , Alternaria and Fusarium oxysporum were identified and isolated from infeted bolls and seeds. The range of incidence of boll rot was 4.9% to 6.32% during the survey period of November 2012 to March 2013. In vitro and in vivo pathogenicity test showed that the F. oxysporum was pathogenic on cotton seedling causing pre and post-emergence seedling mortality. Five fungicides namely Proud 250EC even at 100 ppm and found effective in controlling pre and post emergence seedling mortality and yielded highest germination. Among the varieties tested CB-9 was found more responsive to the treatments. Study showed that, Fusarium oxysporum can be bettter controlled and germination