The South African Sirex Control Programme: Monitoring and biological control guidelines for Sirex noctilio infestations in the summer rainfall regions of South Africa

Verleur PM, Croft PC, Germishuizen I
Publication Type
Technical Note
Publication Year
TN 07-2017

Personnel involved in the initial Eastern Cape and KZN Sirex noctilio outbreak from 2005 to 2008 were also involved in releasing and monitoring levels of parasitism brought about by both parasitoids through Mpumalanga and Limpopo. The experience they gained and parameters which became key in managing the pest, would be beneficial to other Pine growers who had not experienced similar losses through high tree mortality due to S. noctilio. This knowledge has been captured and recorded in these monitoring and bio-control guidelines and if achieved, should avert extensive tree mortality due to S. noctilio.

These guidelines are based on research and lessons learnt from managing the Sirex control programme. The aim is to have a standard which can be used to measure success at a farm or plantation level in the control of S. noctilio against a standard measurement, made up of key indicators such as in the number of trees that are affected annually by S. noctilio, parasitism that is created by Deladenus siricidicola and Ibalia leucospoides, the number of female wasps per log and the climatic risk rating. Commercial pine growers are encouraged to follow these recommended guidelines to inhibit unwanted S. noctilio related tree mortality and outbreaks.

Based on the results measured at the mergence cages, the following recommendations have been made. Areas where reasonable control has been achieved, further monitoring was suggested. Where I. leucospoides is deemed insufficient, then the release of more I. leucospoides is recommended. Should the parasitism created by D. siricidicola be lacking, then further inoculations of D. siricidicola is recommended. If the results are considered unacceptable, then combinations of the above recommendations have been suggested.

All these measures are required when applying the standards set in the matrix Table 3.