Integrated management of sigatoka leaf spot disease of banana (Musa spp.) using newer fungicides

Abstract

The present study was conducted on “Integrated management of Sigatoka leaf spot disease of banana (Musa spp.) using newer fungicides”. The objectives were to conduct survey for assessing the incidence and intensity of Sigatoka leaf spot disease of banana and to evaluate the efficacy of newer fungicides for management of the disease. Survey was conducted in four locations viz. Uzhamalakal in Nedumangad Taluk (Location I), Pallichal in Neyyatinkara Taluk (Location II) and Vellayani in Thiruvananthapuram Taluk (Locations III and IV; Block D and Block F in Instructional farm, Vellayani) indicated that black Sigatoka was prevalent from 2011 to 2012 in the cultivar Nendran. Disease Incidence was 100 per cent and Disease Severity Index (DSI) were 27.30, 29.86, 29.32 and 26.00 in locations I, II, III and IV respectively. Disease Incidence and Disease Severity Index were mainly influenced by maximum temperature ranging from 260C to 320C and high relative humidity of 90-96 per cent. Symptoms of yellow Sigatoka were more severe during the month of May 2013 when the average maximum temperature and relative humidity recorded 32.40C and 95 per cent respectively. Conidia and conidiophore typical to those of Mycosphaerella fijiensis were observed in the microscopic examination of leaf samples and in the culture. Results of the experiment conducted in farmer’s field (Thiruvananthapuram district) on the integrated management of Sigatoka disease, indicated that Azoxystrobin (0.15 per cent) and Tebuconazole (0.1 per cent) were effective in reducing black Sigatoka with concomitant increase in yield. Effect of Tebuconazole was more persistent than that of Azoxystrobin. Integrating fungicides with soil application of biocontrol agent, Trichoderma, was not beneficial in controlling the severity of black Sigatoka except for Tebuconazole (0.1 per cent). Mean per cent increases in yield for the two effective fungicides Azoxystrobin and Tebuconazole were 18.05 per cent and 24.83 per cent respectively over control.