Quick decline of mango in Pakistan: Survey and pathogenicity of fungi isolated from mango tree and bark beetle

摘要

Mango sudden death syndrome (MSDS) has become an increasing threat for mango production all around the world. The present study was conducted to identify the association of pathogenic fungi with mango quick decline tree and the bark beetle. During survey, the most evident symptoms of this disease were gummosis and rotting, cankers and vascular discoloration along with holes made by Hypocryphalus mangiferae. The mango varieties viz., Malda and Ratol were found to be more tolerant against this disease. From diseased tree as well as from H. mangiferae, the most frequently isolated fungi were Lasiodiplodia theobromae, Ceratocystis fimbriata and Phomopsis sp. The isolation of C. fimbriata from beetle on PDA was relatively at low frequency (2.0%) as compared to L. theobromae and Phomopsis (24% and 6.0%). By carrot disc technique, the isolation of C. fimbriata was significantly higher (7.33%) but L. theobromae and Phomopsis sp., were not isolated. The formers fungi were re-isolated from artificially inoculated and symptomatic mango plants. After six months of inoculations, disease symptoms i.e., wilting, oozing and black streaks were developed which showed significant differences among all treatments. Our findings suggested that C. fimbriata and L. theobromae are both pathogenic to mango causing mango quick decline in Pakistan. Both fungi were frequently isolated from diseased tree as well as H. mangiferae which may be involved in the dissemination and as a facilitating agent for the entry of the pathogens.