GRASSY SHOOT DISEASE
Causal organism= Phytoplasma
Symptoms=
· Disease appears nearly 2 months after planting in grassy shoot disease of sugarcane.
· Leaves become pale yellow to completery chlorotic, thin and narrow.
· The plant appears bushy and glass like due to reduction in the length of internodes premature.
· The affected dumps are stunted with premature proliferation of auxiliary buds.
· The buds on such canes usually papery and elongated.
Favourable condition=
· Mono-culturing of sugarcane.
· High day temperature (30-35˚C).
· Low humidity (50-60%).
· Low soil moisture and alkaline soils.
· Excess doses of nitrogenous fertilizers
Disease cycle=
Perennation= through setts and cutting knifes.
Primary infection=
· spread by phytoplasma and
· Through diseased setts and cutting knife.
Secondary infection=
· By aphid viz. meranaphis sacchari.
Management=
Cultural method
· Plant disease free setts.
· Remove and burn the infection clumps periodically.
· Avoid ratooning in problem areas.
· Hot water treatment of setts at 52 degrees for 30 min.
Chemical method
· Aerated stems therapy at 50 degrees for 1hr. followed by steeping in fungicidal solution of carbendazim @0.05% for 15 min.
· Growing resistant varieties viz., Co 86249, CoG 93076 and CoC 22.
· Control vector by malathion or dimethoate@2ml/1L.
