Following up on kiwifruit vine collapse through summer

Plant & Food Research, KVH, and Zespri are working together on a survey of Verticillium species across kiwifruit orchards throughout New Zealand.

This survey is designed to increase our knowledge of Verticillium species currently associated with New Zealand kiwifruit and the project will include testing whether they are a risk. This will also help build knowledge on whether strains associated with kiwifruit in Chile would create a biosecurity risk for New Zealand.

KVH is interested in hearing from growers or orchard managers who might see unexplained and unusual wilt symptoms or sudden collapse of apparently healthy plants over the coming summer months. Often these symptoms are associated with trunk or vine disease, including the Verticillium wilt fungus.

Symptoms are similar to acute water stress, including fruit shrivel and leaves drying out and dying but often remaining attached to the affected shoots. The fungus often blocks only a part of the xylem, with symptoms confined to a section or even one-half of the vine.

Leaf symptoms typically begin with an inter-veinal yellowing before the leaves turn necrotic and die.

Affected vines may suddenly collapse with a full load of fruit in the mid-summer heat. If vines are stripped of fruit, they may appear to recover but can show pale foliage and very stunted or slow growth in the following spring.

Further information about this survey is available here.