The role of Haltica sp. (Coleoptera: Halticidae) with emphasis on host specifity and damage potential in controlling Polygonum chinense was evaluated under laboratory condition.
Starvation test of the weevil on 33 weeds and 14 crop plant species indicated that only 6 weed species were attacked: P. chinense, P. nepalense, P. barbatum, P. longisetum, Ludwigia octovalvis and L. parennis with P. chinense as the most preferred host plant.
Preliminary damage potential test indicated that a population of 0, 1, 2 and 3 pairs of adult weevil reduced the percentage of fresh weight increment of P. chinense by 0; 46.2; 74.7 and 75.5% respectively. Field observations indicated that the larvae as well as adult weevils are potential biological control agents of P. chinense. Further studies are, however, on the host-range of this weevil.