Diseases of fruit plantation medicinal and aromatic crops (2+1)

Grey Blight/ Pestalotiopsis Leaf Spot of mango

Grey Blight/ Pestalotiopsis Leaf Spot

In India, this disease has been reported from many states.
Symptoms
Brown spots develops at the margins and tip if the leaf lamina and distributed irregularly on entire leaf.
Initially the spots are brown and minute and they gradually increase in size and become dark brown. Black dots appear at the center of the spots represent the acervuli.
On mature green fruits, small brown spots appear with grayish white center which later turns to bigger lesions with large number of acervuli seen as black dots.
Etiology
Pestalotiopsis mangliferae (P.Henn.) Stey.
The fungus produces septate mycelia and acervulus as an asexual fruiting body. Conidia are5-celled, oblong to clavate or clavate to fusiform, colored cells are 15-16 micro meter long, upper two of them slightly darker than the lowest olivaceaus colored cells, septa and walls sometimes black and will have long pedicel; setulae 3, coarse, widely divergent and 19-26 micron long.
Mode of spread and survival

• The fungus present in stem is multiplies under favorable conditions. It spread through wind- born conidia.
Epidemiology

• The fungus is capable of growing at temperature between 20-250 c. mycelia growth sporulation takes place at pH 5.5-6.0. Wounding leads to more disease incidence.
Management

• Carbendazim 0.1% after heavy rains followed by wettable sulphur 0.2% before flowering controls the disease. Bordeaux mixture 1.0% can also used for the control.