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 (R) were applied as postharvest treatments. All three products reduced anthracnose development. Bion (R) 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 (R) at 1000 mg L-1. The most effective concentrations of Kasil (R) 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 (R). SER was effectively controlled with 45-28% reduction in lesion area by an higher (three times recommended) dose (2055x3 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.