OUTBREAK OF BACTERIAL APICAL NECROSIS OF MANGO IN MULTAN, PUNJAB, PAKISTAN

Bacterial apical necrosis disease is the serious emerging problems in mango orchards of Punjab, Pakistan. The newly emerged twigs, inflorescence and leaves of the mango trees showed typical symptoms of the bacterial apical necrosis. The bacterium ( Pseudomonas syringae pv. s yringae ) was isolated on nutrient agar and purified on King’s B medium from the symptomatic tissues. Biochemical characterization of the bacterium proved as gram negative having the ability to cause disease in plants. KOH test also countersigned the gram staining observations. Hypersensitivity reaction also showed the ability of pathogen to cause rapid necrosis of tissues within 24 hours of its inoculation. Survey showed the consistent occurrence of the disease in all the selected areas among and within the blocks irrespective of the mango cultivar. Maximum disease incidence was recorded on location-2 with 46.66% while minimum disease incidence was recorded on location-3 with 13.33%. Location-1 ranges from 25 to 41.66% disease incidence while location-2 ranges from 31.33 to 46.66% whereas location-3 ranges from 13.33 to 43.33% disease incidence. This work provides a description on new disease of mango tree in Pakistan which is found almost in every orchard of the mango belt of Punjab. This information will be the valuable tool to study the epidemiology and population genetic diversity of the bacterium in future.