Alternatives to synthetic fungicides in controlling postharvest anthracnose and stem-end rot in mango

Control of postharvest diseases anthracnose and stem-end rot (SER) in mango cultivar 'Karuthacolomban' was attempted using means other than fungicides. The synthetic elicitors Bion^®, salicylic acid (SA) and Kasil^® were applied as postharvest treatments. All three products reduced anthracnose development. Bion^® being most effective at 50 mg L^-1 with over 80% reduction in anthracnose lesion area, SA being effective at 500 mg L^-1 and Kasil^® at 1000 mg L^-1. The most effective concentrations of Kasil^® and SA were applied preharvest as soil drenches or fruit sprays, respectively. Both treatments were effective in reducing anthracnose in harvested fruit. SA sprays were more effective at 500 mg L^-1 on fruit at mid-fill, while 100 mg L^-1 sprays were more effective on mature fruit. Overall, spraying of SA was more effective on fruit at mid-fill, with over 66% reduction in lesion area. A potassium fertilizer was also applied in the field as a separate experiment. Results indicate that all elicitors tested were effective in controlling anthracnose of mango. The most effective being Bion^®. SER was effectively controlled with 45-28% reduction in lesion area by an higher (three times recommended) dose (2055×3 g tree^-1 year^-1) of potassium fertilizer. Total soluble phenols, cell wall bound phenolics and chitinases were induced by SA treatment, while antifungal compounds were increased by Kasil^® treatment.