The Introduction of Bdellodes Lapidaria (Acari: Bdellidae) From Australia Into South Africa for the Biological Control of Sminthurus Viridis (Collembola).

The lucerne flea, S, viridis, was introduced into South Africa with subterranean clover seed imported from Western Australia in 1939. By 1959 the infestation had spread over 50,000 ha and methods of control were examined. The predatory mite B. lapidaria was known to be an effective biological control agent against S. viridis in Australian pastures. From 1963 to 1966 over 75,000 mites were collected in Western Australia and sent by air for immediate release in selected sites in South Africa (Cape Province). The mites were shown to be established in 1965 and multiplied rapidly, enabling redistribution to additional sites. The influence of this predator on S. viridis numbers is now being monitored. Preliminary data indicate that B. lapidaria is capable of influencing flea densities under South African conditions. A definite relationship between the predator and sminthurid Collembola such as S. viridis slnd Bourletiella arvalis is indicated, although B. lapidaria appears to be able to utilize other foods during periods of sminthurid scarcity.