Effect of temperature regimes on pycnidiospore germination of Botryodiplodia theobromae isolates, causing die-back and bark canker of pear in Punjab

Thirteen isolates of Botryodiplodia theobromae Pat. were collected from different pear varieties, grown in Punjab, and temperature optima for pycnidiospore germination of these isolates was assessed under in vitro conditions. Single celled pycnidiospores initiated germination after 8 hr incubation at 15°C. Bi-celled pycniospores of all the isolates were unable to germinate upto 12 hr incubation at 15°C, except B-ML which started germination after 8 hr incubation. Both single and bi-celled showed maximum germination after 24 hr incubation at 30°C.