Psa-V protection following hail

Protection of wounds following hail is important to minimise Psa-V infection, particularly on blocks where Psa-V risk is high. With recent hail damage and the possibility of further hail bands sweeping across the country growers are reminded of their options.

• For blocks where fruit-set has occurred summer rates of copper can be applied. Research and experience from past years show no risk to fruitlets when copper is applied under good drying conditions. Soil applied Actigard™ may also assist.
• For blocks that are flowering, application of copper may compromise pollination of recently opened flowers but this risk needs to be weighed up against the risk of Psa-V infection. BOTRY-Zen® is a biological product registered for use at this time and a soil-applied Actigard™ is also an option.
• For blocks where no female flowers are open, Psa-V sprays should be applied as soon as possible and definitely before the next rain event. The addition of Actigard™ to copper sprays will improve control. Actigard™ must not be used as a foliar spray within producing blocks after the commencement of female flowering (5% flowers open). Ambitious® may be used until seven days before the first female flower opens and KeyStrepto™ may only be applied to blocks where there are no male or female flowers open. Care must be taken to avoid drift or contamination from spray tanks onto fruiting vines.

Alternating sprayer travel up rows in alternate spray rounds will maximise coverage of hail wound sites. Do not spray blocks if bees are actively foraging.

Zespri has further information for growers with orchards affected by recent hail events, including information about insurance cover—click here to view on the Zespri Canopy.