- Due to feeding by the jassids yellowing of leaves start from margin inwards.
- The yellowish discoloured leaves finally become brick red and brown in colour showing hopper burn symptoms.
- The injury is caused due to the toxemia of the insect saliva which is injected in to the leaves during feeding.
- The yield is considerably reduced .
- Due to the weakening of the infested plants the fruits also become small in size and crinkle.
Select 5 pits at random from the plot. Assess the total number of jassids from 6 leaves from each pit( For this select 3rd to 8th leaves from the tip of a vine trailing on the pandal) and work out average per leaf. Less than 5 -Mild,5-10 Moderate >10 severe.