Studies on Management of Spot Blotch of Wheat Caused by Bipolaris Sorokiniana

Abstract

Wheat (Triticum aestivum L.) is an important crop belongs to family Poaceae (Gramineae). After rice, it is the second-most important cereal food in India. Spot blotch of wheat (Bipolaris sorokininan) is responsible for a significant yield loss of 15-20 percent. The present study was undertaken for screening of wheat varieties for resistance against spot blotch and the evaluation of different fungitoxicants, botanicals, bio-agents and micronutrients against spot blotch disease was studied under field conditions and in-vitro as well. In addition, evaluation of different culture media and incubation temperatures for supporting optimum mycelial growth of Bipolaris sorokiniana in vitro was also attempted. Oat meal agar and malt extract agar medium were found to be the best culture media for growth of B. sorokiniana, tomato juice agar media was the best for sporulation of B. sorokiniana. Among different temperatures level, 250C temperatures was best for highest radial growth and 270C was the best for highest sporulation of B. sorokiniana. In-vitro evaluation of micronutrients against mycelial growth of the pathogen showed that highest growth inhibition was exhibited by ferrous sulphate which was found highly effective after seven day of inoculation. In case of Fungitoxicants, Propiconazole, Tebuconazole, Difenoconazole and Azoxystrobin + Tebuonazole were most effective at all the concentration against B. sorokiniana in-vitro. Plant extract i.e., Garlic at 15 percent concentration was found highly effective in inhibiting the growth of the pathogen in-vitro. Among bio-agents, highest growth inhibition was exhibited by Trichoderma harzianum (IRRI-1). It was found that among thirty-two wheat varieties screened under field conditions, two varieties were found moderately resistant, fourteen varieties were found moderately susceptible and five varieties were found susceptible and none of the varieties were found immune and highly susceptible for spot blotch of wheat. Propiconazole and Tebuconazole were almost equally effective and may be used as an alternative to each other for effective management of spot blotch in wheat. Among botanicals tested against spot blotch of wheat, highest reduction in disease was exhibited by Garlic clove extract as compared to other botanicals. In case of bio-agents Trichoderma harzianum (IRRI-1) was found to be superior than other bio-agents which resulted in highest reduction of spot blotch disease in wheat.