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

Rust of grapes

Rust disease is incited by Physopella vitis Syd.

• In Tamil Nadu, this disease has been reported from Salem, Dharmapuri, Nilgiris and Coimbatore districts.
• Generally the variety, Black Prince is affected, besides attacking some wild species of Vitis.
• This disease is generally observed during winter season.
• The fungus produces numerous orange coloured sori on the lower surface of leaves. In severe cases of infection, entire leaf surface is covered by the orange coloured sori followed by defoliation occurs.
• Uredospores are binucleate with hyaline or coloured walls. These are echinulated and borne singly on pedicels .
• Teliospores found in several layers. Which are sessile and not echinulate. These are single celled with one germ pores and wall is pigmented
• The fungus attacks only the blue coloured grapes than green ones
• The disease can be controlled by spraying Zineb (0.2%) or wettable sulphur (0.2%) or dusting sulpur at 25 kg/ha.