Globally, the occurrence of insect pests has increased, threatening pest management efforts in a number of sectors, including the forestry sector.  Therefore, new control measures are sought that are specific, environmentally friendly and can be developed in a relatively short period of time. The discovery of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) shows much potential to be implemented for gene editing in insect pests, for a genetic pest management approach.

Before genetic pest management approaches can be implemented, a first step involves successfully transforming individuals of the insect pest of interest. In insects, embryo microinjection is commonly used, but this method relies on availability of large numbers of eggs as the mortality rate associated with microinjection is high. In S. noctilio, development of a gene editing protocol has necessitated investigating methods to obtain large numbers of eggs for microinjection. As females of the woodwasp Sirex noctilio do not readily oviposit sufficient eggs for use in microinjection, a novel approach was developed to obtain eggs. This approach entails the use of eggs dissected from S. noctilio females and subsequent application of mechanical pressure to initiate the further development of the egg. It is thought that eggs require substantial pressure to initiate development and in natural settings this pressure is achieved when the egg passes through a narrow ovipositor. The newly developed egg activation technique, highlighted in a news item by Nature Africa, will not only be essential for gene editing in S. noctilio but will also enable further studies on the biology of S. noctilio.

This work formed part of the Masters study of Elmarie van der Merwe, under the supervision of Dr Gudrun Dittrich-Schröder and Prof. Bernard Slippers, and was supported through funding obtained from the Future Leaders –  African Independent Research (FLAIR) Fellowship and the TPCP. Further details of this work are available in the publication, which appeared in Insects in December 2023.