Look-out for trunk disease indicators

As crops move through to flowering growers and managers regularly monitor vines to inform hive placement, flower picking and pollen application decisions. This period is also a perfect time to monitor for unusual symptoms and disease indicators.

Unusual die-back symptoms can flag underlying vine diseases such as Neonectria micronidia, which can cause trunk and leader swelling with associated cracking, as well as swollen cracked areas at the graft union. View a set of recent symptom images here.

Visits to orchards in recent weeks have highlighted that these symptoms can be present but unseen unless there is a concerted effort to follow-up on early indicators such as cane and leader die-back. Unusual trunk symptoms such as bulges similiary indicate the likelihood of vine infections – see an unusual trunk canker image here.

Phytophthoras may also be affecting vine health. Phytophthora species are soil-inhabiting pathogens that are favoured by wet conditions and so may be causal in the decline or collapse of vines suffering extended periods with “wet feet” – see an example of an affected vine here. Current industry research projects are looking for sites with symptoms relating to each of these diseases – please contact [email protected] for more information if you are interested in taking part.

Vine health is key to fruit quality, so if incidence of vine symptoms is being seen, an ongoing vine replacement stategy is highly recommended. There are good numbers of excellent quality kiwifruit nursery stocks available through the KPCS nursery scheme.