Abstract:
A new disease (cashew leaf and nut blight) in Tanzania caused by a fungus related to the genus
Cryptosporiopsis was identified in 2006. The present work investigated the effects of environmental
factors on the growth of Cryptosporiopsis spp. causing blight on cashew. The mycelial growth, colony
character and sporulation pattern of 10 fungal isolates, grown on seven different culture media namely,
corn meal agar (CMA), malt extract agar (MEA), tryptone dextrose agar (TDA), potato carrot agar (PCA),
water agar (WA), potato dextrose agar (PDA) and host leaf agar were observed after 10 days of
incubation at 25±2°C. The colony diameter, culture characteristics and sporulation of the 10 isolates
were greatly influenced by the type of growth medium used. The best mycelial extension was recorded
in 12 h alternating light/dark followed by total light and total dark conditions, respectively. Seven media
were evaluated for best growth of the fungi that is, Cryptosporiopsis spp. grew maximum on WA
followed by host leaf extract media and PDA, respectively but least grew on the TDA medium. The
growth of Cryptosporiopsis spp. was maximum in temperature range of 25 to 30°C. The most suitable
pH level for growth of fungus was 7.0 and 6.0. These results will be useful for fungal taxonomic studies.