Favorable morphological and cultural conditions for mycelial growth of Sclerotium rolfsii(curzi) C.C Tu & Kimber, causing stem blight of tomato

Abstract

Tomato is subjected to a number of diseases at all the stages of its development from nursery to the consumption of the tomatoes. Among all the diseases infecting tomato, the stem blight of tomato is the most severe threat for the tomato industry and also for foreign exchange earnings. This disease is incited by number of pathogens but the major causal organism is Sclerotium rolfsii (curzi) C.C Tu &Kimber. Out of five solid media were used potato dextrose agar (PDA) was the best solid media for the growth of mycelium and highest sclerotial production was observed in sabouraud’s dextrose agar(SDA). Starch and dextrose were recorded best carbon source while sodium nitrate and potassium nitrate were found to be the best nitrogen source for the growth of Sclerotium rolfsii. The pathogen grew between 5ºC to 40ºC, with maximum mycelial growth at 30ºC, with highest sclerotia formation. The hydrogen ion concentration 6.5 showed maximum mean diametric growth and sclerotial production.