Efficacy of Newer Fungicides Against Leaf Spots Caused by Alternaria Tenuissima and Cercospora Sojina in Soybean

Abstract:

The efficacy of newer fungicide was evaluated against leaf spots of soybean caused by Alternaria tenuissima and Cercospora sojina.  In the field experiment, the percent disease index of Alternaria tenuissima by using two sprays of Azoxystrobin 5.6% w/v + Tebuconazole 10% w/v + Prochloraz 20% w/v EC (0.2%) 3 ml/L in treatment T3 at 15 days interval resulted from 8.45 and  9.80 % at 55 and 70 DAS respectively. It was at par with treatment T2 resulted in percent disease index 8.52 and 9.88 at 55 and 70 DAS respectively over control. Treatment T3 recorded the highest Alternaria leaf spot disease control, i.e. 44.48 and 47.73 respectively at 55 and 70 DAS and was followed by treatment T2, i.e. 44.02 and 47.31. Similarly, for Cercospora sojina in treatment, T3 recorded the least disease index 6.90 and 8.10 at 55 and 70 DAS respectively, resulting in percent disease index 6.96. It was at par with treatment T2, resulting in percent disease index 6.96 8.14 at 55 and 70 DAS respectively over control. The highest per cent disease control of Cercospora sojina was recorded in treatment T3, i.e. 62.74, followed by in treatment T2 i. e.  62.56 at 70 DAS. Maximum yield 1184 kg/ha was recorded in treatment T3 sprayed plots, and it was at par with T2 1146kg/ ha while minimum yield was obtained in untreated control 638kg/ha. Two sprays of T2 at 55 and 70 DAS has been advocated for the management of both Alternaria tenuissima and Cercospora sojina leaf spots of soybean.