Growing mangoes is full of challenges one of these is anthracnose. Proper identification and control is important.
Anthracnose is a fungal disease that thrives well in wet and dump conditions and affects both leaves and fruits. It‘s major damage is caused in the field but also a problem even after harvest. The fruits can only show black spots on harvest but the spots continue to grow and may make the mangoes un marketable especially for the export market.
Anthracnose symptoms
The most visible symptoms of anthracnose are black spots on the leaves. They begin small but get bigger until they cause holes in the leaves. On the flower, the disease also causes little black spots on the panicle and on later stages, the flower changes colour and dies. On the fruit, the damage can appear as soon as the fruit is formed. The fruit can die soon or and fall off or remain; those that remain are a source of infection.
Control measures
Manual control involves regularly scouting of the field for any sign. Anthracnose is predictable and appears after rain. Remove all infected parts and also cut the top of the canopy to create a window that enables free circulation of sunlight and air.
Chemically, fungicides can be used but are not effective alone and work along manual control. Fungicides are either systemic or contact. Use contact when first flashes occur. Shortly before flowering, use systemic while at flowering, do not use any fungicide and after flowering, apply contact fungicide. Keep alternating contact and systemic every 3 to 4 weeks and within the contact and systemic, alternate the active ingredients. Stop spraying 3 weeks to harvest.
To know amount of fungicide needed, mix water with a food colourant and completely drench the tree. Check how much liquid was used and use this to estimate the amount needed for the entire farm. During spraying, spray every tree correctly, start with the inside of the tree, move to the outside, spray at the top and wet your way down and round the canopy ensuring all parts are covered.
