S2.07-00 Entomology

Poster 156: The Biological Control of Phoracantha semipunctata and Phoracantha recurva (Coleoptera: Cerambycidae) in South Africa

Kirsten, F., Tribe, G.

P. semipunctata and P. recurva, native to Australia, were inadvertently introduced into South Africa around the turn of the present century.

In 1910, the first attempt to control phoracantha beetles was made with the importation of a number of unidentified Megaliridae wasps. Failure to establish a laboratory culture led to the curtailment of the project, with no records of any releases having been made. In 1962 and again in 1993, relatively large numbers of the Australian wasp, Magalyra faciipennis, were recorded in the winter rainfall regions, presumably part of the 1910 consignment.

In 1969 the braconid parasite, Syngaster lepidus, was introduced into South Africa and a small number were released in 1971. Only one female has since been recovered.

Severe drought conditions in much of the summer rainfall areas during 1991 to 1993, resulted in an outbreak of phoracantha beetles causing severe damage to Eucalyptus plantations. With renewed interest in controlling phoracantha beetles a braconid larval parasite, Cleonymus sp., of unknown origin was recorded, and two consignments of Megalyra faciipennis, from the winter rainfall region, were released in the affected areas. In 1992 an Australian encyrtid egg parasite, Avetianelle longoi, was introduced into South Africa which has since become established in the winter and summer rainfall regions, attaining a parasitism rate of 6080%. In collaboration with the Plant Protection Research Institute (South Africa), the International Institute for Biological Control (Kenya Station) and the Department of Forestry of Zambia, the egg parasite, Avetianella longoi was released at on locality in the South-eastern province of Zambia during February 1995.

Further introductions of larval parasites for the control of phoracantha beetles are being considered for 1995.

Key words: Phoracantha semipunctata, Phoracantha recurva, biological control, eucalyptus, South Africa.

Correspondence: F. Kirsten, Plant Protection Research Institute, P.O. Box 189, Sabie 1260, Republic of South Africa

Telefax: +27-1315-43327