Powdery mildew is a very serious disease of mango, affecting almost all cultivars in all mango-growing regions of the world. It is caused by the fungus Oidium mangiferae and causes extremely high reductions in yield.
The fungus attacks inflorescences, leaves, and young fruits.
The characteristic symptom of the disease is the whitish, superficial, powdery fungal growth, mainly on inflorescences. Affected flowers do not open and in most cases, they shed prematurely. Young fruits may also be covered with powdery growth and drop off prematurely. Poor fruit set and heavy flower and fruit drop result in severe yield losses, sometimes reaching as high as 70-90% on an individual plant.
Disease Cycle
Oidium mangiferae survives from one season to the next as mycelium in dormant buds and as haustoria on old infected leaves.
After landing on the plant tissue, a conidium of O. mangiferae germinates, enters a stoma/pore and then grows. After two or three weeks, the fruiting bodies grow out of the stomata and release conidia into the air, to be carried to other plants or plant parts.
It usually takes about 7-10days from the time of infection to development of symptoms.
The disease is spread by wind-borne conidia from other mango trees or from within an infected tree’s canopy.
Initial infection with O. mangiferae is promoted by warm temperatures and moderate relative humidity, although development of the disease is favoured by cool, dry conditions.
The fungus survives under dense foliage during off-season.
17 сен 2024
