On fruits initially few black pustules appear which later develop in to a ring.
The pustules join together and cover big area of the fruit.
On leaves, pinkish brown pustules develop which may be arranged in group or scattered as infection of fruit does not go on leaves and vice-versa.
Teleospores of Ravenelia emblicae causes the fruit and leaf infection
Favourable condition is after monsoon in September
Smoke brown to black round lesions develop on fruits within 2-3 days of infection.
The diseased parts later show olive brown discoloration with water soaked areas extending toward both the ends of fruits forming an eye shaped appearance.
Infected fruits become dark brown, crinkled with softening of underlining tissues and get deformed.
Fungus causes infection both in young and mature fruits, but mature fruits are found to be more susceptible.
Disease is favored by hot and wet weather. The optimum temperature for fungal growth is 29˚C and it grows well up to 32˚C.
Nutritional Deficiency/ Disorder
Internal necrosis in amla fruits is caused by Boron deficiency.
The symptoms start with the browning of the innermost part of mesocarpic tissue at the time of endocarp hardening in the 2nd or 3rd week of September which later extends towards the epicarp resulting into brownish black appearance of the flesh.
Control measures: Spray 0.6% borox during September to October thrice at an interval of 10-15 days.