Hail damage adds to Psa risk

14 November 2019

Wild spring weather, including hail storms in the western Bay of Plenty, continues to add Psa risk for many sites across growing regions.

Damaged leaves and canes should be protected with copper to minimise infection risk, especially if there is already a high inoculum source due to heavy leaf spotting across blocks. Psa control options reduce as blocks move through to flowering but late flowering sites may still have a window to apply Actigard. This is highly recommended, particularly for wind prone sites. Ensure young plants or grafts are also protected.

When applying coppers, maintain a five to seven-day gap between applications of foliars and copper to minimise risk of phytotoxicity to leaves and fruit. Do not apply sprays in poor drying conditions, or high humidity, as risk of fruit staining increases.

Gold skin sensitivity commences around 21 days after fruit set with risk increasing between 28 and 42 days and reducing again between 42 and 80 days. For Hayward, 14 to 35 days after fruit set is considered a high-risk period. Copper may be applied during these periods but take care to ensure drying conditions are optimal.

The Psa Risk Model indicates ongoing moderate risk from most stations over the next week so take every opportunity to prune male vines and complete girdling in the dry. Follow up with copper spray. Apply wound protectants to all large cuts.

Refer to the KVH recommended product list for more information about summer rates.