A CASE STUDY FOR THE OCCURRENCE OF BACTERIAL LEAF SPOT OF MANGO IN PUNJAB (PAKISTAN)

Abstract

A survey was conducted for bacterial black spot disease in different districts of Punjab. Maximum disease incidence was observed in Multan followed by Muzaffar Garh and Khanewal while minimum disease incidence was noted in Jhang and Lodhran district of the Punjab. Thirty symptomatic samples were collected from multiple locations and associated pathogens were isolated. Bacterial isolates were inoculated on different mango cultivars to evaluate the level of resistance. None of the cultivar was resistant against the disease although Anwar Ratool and Late Chounsa were least affected. Eighteen isolates were grown on asparagine and nutrient agar with 5% glucose medium to check their variability which depicted round, convex, creamy white and yellow pigmented colonies with entire margins. Mucoid colony growth was found when inoculated on nutrient agar with 5% glucose. Biochemical tests showed that all bacterial isolates were gram negative, salt tolerant, oxidase negative and showed negative growth while grown on asparagines medium. On the basis of these tests bacteria were found as X. campestris. Although yellow pigmented isolates were found less aggressive as compared to creamy white ones.