A recent resistance workshop has highlighted the value of ongoing monitoring programmes and the need for a comprehensive Psa control programme.

Hosted by KVH and Zespri, the workshop was held earlier this week with representatives from the science community and agrichemical companies to discuss the ongoing evolution of copper resistance Psa and how we best respond to this.

The resistance monitoring programme has enabled us to detect resistance Psa bacteria early, and to identify the mechanisms/changes that led to this resistance. This means we have an opportunity to learn more about the bacteria and how we best respond to the changes before the levels of resistance build and potentially impact Psa control on orchards. Historically resistance is usually found when chemicals fail to control disease pressure, which can result in the loss of that compound from the control programme, something we can’t afford to have happen with Psa since we have so few control products available.

Although we have identified resistance Psa bacteria on orchards we have not seen control product failure, but the workshop agreed that continued intensive monitoring is important (on a selection of orchards) to better understand the rate of resistance development and risk to the industry.

It was also agreed that based on current knowledge, KVH Best Practice advice around Psa control to reduce resistance development is appropriate and should continue to be followed by growers. Further research areas were identified to enhance KVH’s recommendations.

KVH and Zespri are also focussing on finding additional control products to reduce reliance on copper over time.