Fungicidal Management of Stemphylium blight of Onion caused by Stemphylium vesicarium (Wallr.) Simmons

ABSTRACT: Onion is an important commercial crop grown all over the world. It is attacked by many diseases which cause yield losses and result in lowering the quality and export potential of the produce. Stemphylium blight caused by Stemphylium vesicarium (Wallr.) Simmons is one such disease, which has become an economic threat since past few years, especially in Northern and Eastern India. In the present study, field evaluation as well as in vitro study was conducted for evaluating some fungicides for the management of Stemphylium blight as well as to observe their effects on yield and quality parameters of onion. The results of the in vitro study revealed that fluopyram + tebuconazole gave complete mycelial inhibition of test fungus at 50 ppm concentration. Results of the field experiments showed that all the treatments significantly reduced the disease severity. However, strobilurins were found to be more effective, giving more than 50% disease control over check. Keeping in view the overall performance of the fungicides, it was concluded that the combination products azoxystrobin 25% + flutriafol 25% SC and fluopyram 20% + tebuconazole 20% SC can be recommended for the management of Stemphylium blight of onion under field conditions.