A review of the role for natural defences in the management of Colletotrichum rotting of ripe mangoes
Anthracnose and blossom blight, caused by Colletotrichum species, are two most destructive diseases in mango. Anthracnose can occur at any stage of fruit development resulting in pre- and postharvest losses. Colletotrichum species cause quiescent infections in mature fruits which develop in to progressive anthracnose rots during fruit ripening. Fruit losses due to anthracnose may be reduced if fungal infections are kept in their quiescent state for extended periods. A possible way of prolonging quiescence is to maintain the natural antifungal barrier in the unripe fruit at an inhibitory level in to the post-climacteric phase. Unripe mangoes contain resorcinols and chitinase in the latex and gallotannins in the peel constituting fruit resistance at immature stage. Their gradual decline during ripening makes the fruits susceptible to fungal rotting. Mango peel tissue responds to Colletotrichum challenge by several early defences and enhanced phenolics and enhanced gallotannins and chitinase activity. Latex disappears in coincidence with ripening and the decline of fruit resistance. When latex was retained by harvesting fruit with a portion of pedicel, the incidence and severity of anthracnose were significantly reduced. Fruit peel in which latex was retained had greater chitinase activity than controls. Latex plays a direct role in fruit resistance to anthracnose. Elicitor treatment enhanced fruit resistance and reduced the incidence of anthracnose in ripe mangoes. Constitutive antifungal substances could also be useful markers in the selection of resistant cultivars to postharvest fungal pathogens.
Adikaram, N.K.B., Karunanayake, L.C., Sinniah, G.D., Abayasekara, C.L., Komala Vithanage, S. and Yakandawala, D.M.D. (2017). A review of the role for natural defences in the management of Colletotrichum rotting of ripe mangoes. Acta Hortic. 1183, 229-232
Colletotrichum, mango, anthracnose, resorcinols, gallotannins, chitinases