Studies on physiological parameters of Choanephora cucurbitarum, the incitant of wet rot of cucumber

Abstract

A newly documented disease, namely Choanephora wet rot of cucumber (Cucumis sativus L.) caused by Choanephora cucurbitarum was found at SKN COA, Jobner, in Zayad 2014. The colonies of the causal fungus grown on potato dextrose agar at 25°C are white at the early stage of growth with abundant aerial mycelium, but at later growth stages turn pale yellow. Sporangia and sporangiola are readily observed on the tip of upright sporangiophores, which are numerous on aerial mycelium. Effect of temperature, RH and media on mycelia growth of Choanephora cucurbitarum was studied in vitro. Maximum mycelia growth was found at 25 C and 30 C. 100% relative humidity favours the disease also. A significantly decrease in mycelia growth was observed at 70% relative humidity. Among five different media PDA was found superior. This was followed by martin medium. Mycelial growth was not recorded on Oat meal agar.