Table 3 Grading of different genotypes based on infestation symptoms (Sikka et al. 1966)

1

Leaves free from crinkling or with no yellowing, bronzing and drying

2

Few leaves on the lower portion of the plant curling, crinkling and slight yellowing

3

Crinkling and curling all over, yellowing, bronzing and browning in the middle and lower portion, plant growth hampered

4

Extreme curling, yellowing, bronzing and browning, drying of leaves and defoliation, stunted growth