Effect of Light on Growth and Sporulation [Colletotrichum truncatum (Schw.) Andrus and Moore] Causing Anthracnose of Mungbean

Mungbean [Vigna radiate (L.) Wilczek] is an important pulse crop grown widely inentire Indian Sub-continent during rainy and summer season. The average productivity of mungbeanin India is very low due to several abiotic and biotic stresses. Anthracnose, caused by Colletotrichum truncatum (Schw.) Andrus and Moore, isone of the most important fungal diseases of greengram (Vigna radiate L. Wilczek). The experiment was conducted in vitro conditionto study the effect of light on the fungal growth rate, type of growth and sporulation by exposing the culture to alternate cycle of 12 hr darkness followed by 12 hr light, continuous darkness and continuous light for eight days. C. truncatum isolated from infected mungbean leaves was grown in poured petri plates. Light is playing an important role in disease development. In the present study, the results revealed that alternate cycles of light and darkness, as well as the continuous darkness supported maximum growth and excellent sporulation of the pathogen. However, maximum fungal growth was recorded in the treatment of alternate cycles of light and darkness, whereas least growth and sporulation was recorded in culture exposed to continuous light. Physiological studies revealed that exposure of petridishes to alternate cycle of 12 hr light under day light and 12 hrs darkness resulted maximum mycelial growth of the fungus to the tune of 81.78 mm as well as excellent sporulation. Similarly, exposure of petridishes to continuous darkness resulted in production of mean colony diameter of 67.35 mm with excellent sporulation. The least mean colony diameter of 60.58 mm was observed in the petridishes which was exposed to continuous light with good sporulation. Pigmentation of the fungus also varied from white to pink.