GREEN GRAM ::MAJOR DISEASE :: RUST

Rust - Uromyces phaseoli typica(Syn: U. appendiculatus)
Symptoms
            The disease appears as circular reddish brown pustules which appear more commonly on the underside of the leaves, less abundant on pods and sparingly on stems. When leaves are severely infected, both the surfaces are fully covered by rust pustules.  Shriveling followed by defoliation resulting in yield losses.
Pathogen
It is autoecious, long cycle rust and all the spore stages occur on the same host. The uredospores are unicellular, globose or ellipsoid, yellowish brown with echinulations. The teliospores are globose or elliptical, unicellular, pedicellate, chestnut brown in colour with warty papillae at the top. Yellow coloured pycnia appear on the upper surface of leaves. Orange coloured cupulate aecia develop later on the lower surface of leaves. The aeciospores are unicellular and elliptical.
Favourable Conditions

• Cloudy humid weather,
• Temperature of 21-26˚C
• Nights with heavy dews.

Disease Cycle
The pathogen survives in the soil as teliospores and as uredospores in crop debris. Primary infection is by the sporidia developed from teliospores. Secondary spread is by wind-borne uredospores. The fungus also survives on other legume hosts.
Management

• Remove the infected plant debris and destroy.
• Spray Mancozeb 1 2 kg or Carbendazim 500 g or Propiconazole 1L/ha kg/ha, immediately on the set of disease and repeat after 15 days.
• Use tolerant varieties.