It’s Citrus Gall Wasp season again! It has been a warmer than average year so adult wasps will start emerging in early October with peak emergence expected around the 19th of October.

Words Helen Newman Biosecurity Officer, WA Citrus

TO keep your orchard free of this pest, thoroughly inspect and treat all new planting materials coming on to your property.

You can also check the perimeters of your orchard for any signs of galls. Remember —galls can be small and will be present on the spring flush from the previous year. Focus your efforts on the side of the orchard facing the prevailing October to December wind and areas facing residential areas and any other potential sources of infestation. Prune out and destroy any galls and report your findings to MyPestGuide.

If you read my article on the APVMA permit process (page 33) you might be wondering what chemicals are available for managing Citrus Gall Wasp. The last Citrus Strategic Agrichemical Review Process (SARP), conducted in 2022, identified Citrus Gall Wasp as a high-priority pest in NSW, QLD, SA, and VIC.

The SARP also identified that the two main chemicals used to manage the pest, Confidor® (imidacloprid) and Samurai® (clothianidin), are under review, and maintaining access to these chemicals is of significant concern.

Calcinated kaolin (Surround®) is the only alternative chemistry identified in the SARP for Citrus Gall Wasp and is not currently at risk of regulatory review.

Along with pruning, spring applications of Surround® , coinciding with adult wasp emergence, are a viable option for managing Citrus Gall Wasp.

It irritates and repels the wasp, disrupting egg laying. Surround® can also disrupt beneficial insects and exacerbate other pest issues such as red scale and two-spotted mite, so care must be taken with its use. Research by the NSW DPI into the potential for releasing parasitic wasps to predate Citrus Gall Wasp continues.

From a pesticide access perspective, the APVMA classifies oranges and mandarin as major crops, and lemons, limes, tangelos, and grapefruit as minor crops.