Studies on Xanthomonas axonopodis pv. Punicae, causing bacterial blight of pomegranate in Punjab

Bacterial blight of pomegranate caused by Xanthomonas axonopodis pv. punicae, have economic importance to reduced crop yield in India. Farm survey was undertaken in the pomegranate research block, Fruit Research Station, Jallowal-Lesriwal Jalandhar during 2015. It was revealed that the maximum disease incidence (91%), severity (14.41%) and fruit cracking (12%) was found in cv. Ganesh. Twenty isolates of Xanthomonas axonopodis pv. punicae showed different virulent reaction with respect to incubation period, fruit cracking and drooping. It was observed that 9 isolates viz. Xap4, Xap5, Xap6, Xap9, Xap12, Xap14, Xap15, Xap16 and Xap17 were highly virulent on Ganesh cultivar. The optimum growth of bacterium was observed at 30°C while 5 and 50°C temperatures did not show any growth on Kings B Medium. All the five chemical treatments showed control of bacterium under in vitro conditions. However, the combination of Blitox (2500ppm) and Kocide (2500ppm) with Cristocycline (100ppm) showed maximum inhibition zone of 53 and 52 mm respectively followed by streptomycin (50.12 mm) and Cristocycline (50mm) with 500 ppm concentration. While Bordeaux mixture with concentration (1%) showed 45 mm inhibition.

The pathogen Xanthomonas axonopodis pv. punicae isolated and characterized. Find the favorable temperature for their growth and antimicrobial agent's under in vitro condition.