author(s)
TD Jayabal, C Chinniah and M Kalyanasundaram

abstract
The trichome density on leaves of okra germplasms collections was maximum 177/ cm² of leaf area on IC 117235 and it was minimum 9/ cm² leaf area in IC 014600. The correlation studies (r) between trichome density and T. urticae incidence revealed that the number of trichomes / cm2 leaf area on upper surface, lower surface, midrib, veins and total trichome density revealed a significant negative impact on the T. urticae population build up in the okra entries screened. From the correlation analysis, it is evident that an increase in total trichome density by one unit / cm² leaf area, there was a significant decline in population of T. urticae by 0.13 per cent. As for as trichome length is concerned, it was the maximum 25.51µm on IC 031850 on the upper surface, EC 329421 and IC 018532 (29.59µm) on the lower surface, IC 031850 (35.65µm) on the midrib and veins (29.82µm) of IC 031850. The correlation studies (r) between trichome length and T. urticae population revealed that the trichome length exhibited significant negative correlation on okra entries screened. Multiple linear regression fit revealed that the contribution of trichome density and length towards the population build up of T. urticae in okra was significant to an extent of 92.80% and 92.23% respectively. Thus, presence of trichomes acts as a major resistant factor against bhendi mites.