- The affected vines exhibit shortening of internodes to varying degrees. The leaves become small and narrow with varying degrees of deformation and appear leathery, puckered and crinkled.
- Chlorotic spots, yellow flecking, dark green vein banding also appear on the leaves occasionally.
- Internodes of vines become abnormally short leading to varying degrees of stunting of plants.. In very severe cases the vine sheds leaves and berries leaving a leafless vine.Vines seldom die due to this disease complex, but continue to decline and spike and berry formation ceases gradually.
Major mode of spread of the viruses is through the use of infected stem cuttings. The viruses may even take 2-5 years to express the typical symptoms depending on varieties, age of vine, nature of virus strains, climatic conditions, ,vector associated ,etc. The disease can also be transmitted through insects like aphids,(Aphis gossypii) citrus mealy bugs (Planococcus citri,Pseudococcus elisae,Ferrisia virgata) and pepper lacewing bug (Diconocoris distanti).
Select 20 standards at random and look for typical symptoms. Work out the % of incidence. Get it confirmed from laboratories having virus indexing facilities.