Assessment of Paulinia acuminata (Orthoptera: Acrididae) for the biological control of Salvinia molesta in Australia.
Fifty-three species of plants representing 38 families and including crop plants, aquatic plants and weeds were exposed, together with the aquatic weed Salvinia molesta, to adults and nymphs of Paulinia acuminata in studies conducted in quarantine in Australia. Adults fed on 18 of the plants, but nymphs failed to feed on 9 of these. In starvation trials without S. molesta, 16 plants were attacked by adults; of these, only 7 were attacked by nymphs. Females oviposited only after feeding on S. molesta, Azolla pinnata, water lettuce (Pistia stratiotes) and water hyacinth (Eichhornia crassipes), but eggs laid after feeding on the latter plant failed to hatch. Heavy feeding occurred on the leaves of strawberry (Fragaria × ananassa) but no oviposition occurred. The developmental period of the pauliniid on S. molesta was about 67 days at 25°C. Laboratory evaluation of the potential of the pauliniid as a biological control agent were supplemented with observations on its distribution and abundance on salvinia in the Zambezi River system, Zimbabwe, where it had been introduced from South America in October 1984.