BIOLOGICAL-CONTROL OF ALLIGATOR WEED - UNSUCCESSFUL ATTEMPTS TO CONTROL TERRESTRIAL GROWTH USING THE FLEA BEETLE DISONYCHA-ARGENTINENSIS [COL, CHRYSOMELIDAE]

Biological control of alligator weed growing in aquatic habitats in Australia is successful but the agents, a flea beetle Agasicles hygrophila and a moth Vogtia malloi, do not control terrestrial growth. Consequently another flea beetle Disonycha argentinensis was introduced into Australia specifically to control the terrestrial growth. Progeny of adults collected in Brazil from areas similar in climate and habitat to areas infested with alligator weed in Australia, were released but failed to become established. Eggs were laid by females released into a large field cage and some completed development, but the new adults failed to reproduce. Tentative conclusions are that microclimate or predation may have prevented establishment of D. argentinensis but the results should not preclude attempts to establish this insect in North America, China or elsewhere.