Potential of fungicides and plant activator for postharvest disease management in mangoes

Mango fruit quality, marketability and shelf-life are adversely affected by post-harvest disease development. The fungicides and plant activators suppress the disease development in fruits and vegetables. These studies were targeted to evaluate the potential of pre and post-harvest fungicidal applications and on-tree foliar spray of a plant activator viz. a viz. salicylic acid for post-harvest disease management in two commercial mango cultivars (Sindhri & Samar Bahisht Chaunsa) of Pakistan. Alternaria alternata (49.3% in Sindhri; 58.5% in Chaunsa), Phomopsis mangiferae (20.0% in Sindhri; 18.2% in Chaunsa) and Botryodiplodia sp. (3.9% in Sindhri; 2.7% in Chaunsa) were found to be associated with mango fruit stem end rot (SER) under agro-ecological conditions of Punjab, Pakistan. Penecillium sp. and Aspergillus sp. (A. niger & A. flavus) were identified to be associated with secondary infections in the diseased mango fruit tissues. Among the post-harvest diseases, fruit side rots were predominant (5-10% affected area) followed by stem end and distal end rots (less than 5% affected area). Post-harvest fungicidal treatments gave significantly better disease control as compared to pre-harvest applications. Post-harvest hot water (52 degree C; 5min) application of Tecto (1.8 mL/L) a.i. Thiabendazole (TBZ) individually and in combination with Sportak (0.5 mL/L) a.i. Prochloraz (tank mix) resulted in significantly lower post-harvest disease development than other pre and post-harvest treatments. Pre and post-harvest fungicidal applications significantly affected fruit peel color development. Relatively better color development was observed in the fruit subjected to post-harvest fungicidal treatments as compared to pre-harvest applications. Non significant effect of both pre and post-harvest fungicidal treatments was observed on biochemical quality attributes (TSS & titratable acidity). On tree foliar sprays of salicylic acid (250, 500 & 1000 muM) in cvs. Sindhri and Samar Bahisht Chaunsa at the time of panicle pushing/flower opening, fruit set and stone hardening could not perform well against post-harvest disease development.