During bud-rot trials in Hayward and Green14 orchards last year, Actigard™ and copper spray programmes had the biggest impact in reducing Psa-V leaf spot. Applications of KeyStrepto™ also reduced leaf spot.

As Psa-V is associated with bud-rot, a protective programme that includes these products is highly recommended for all sites vulnerable to bud-rot. This will minimise leaf spot, which once established, can provide ongoing sources of inoculum.

Girdling provided the best bud-rot control. Recommended timing for girdling is 16-30 days pre-flowering. Further trials will run this year to better understand optimal girdle timing.

Growers intending to apply a pre-flower girdle should plan for this now. All growers are urged to measure impacts of this treatment on their site and share this information with the industry to build knowledge quickly about the value of this tool.

By leaving some control vines amongst girdled areas or alternatively, girdling only a few vines within high-risk blocks and measuring flower-to-fruit retention, assessment of the success of this tool across multiple sites can be gained. A methodology to assist growers has been developed by the Zespri OPC team – click here.