Evaluation of products for control of Nectria galligena on apples

Project summary:

Canker, caused by the fungus Neonectria ditissima, is one of the most important diseases of apple and pear. The fungus attacks trees in the orchard, causing cankers and die-back of young shoots, resulting in loss of fruiting wood and increasing pruning costs. Apple canker can be particularly damaging in young orchards where, in some years, up to 10% of trees can be lost annually, in the first few years of orchard establishment, as a result of trunk cankers. Nectria also causes a fruit rot that can result in significant losses as high as 10% or more in stored fruit. Currently, fungicides effective against canker, particularly for use in the growing season, are limited. There are several new fungicides currently being evaluated in the Sceptre project for powdery mildew which may also be active against Nectria. This project would test these chemicals, biocontrol agents such as Serenade and alternative chemicals, for their efficacy in controlling Nectria canker and fruit rot, and identify how best to use them in the growing season. The information generated from the project will be reported to the industry through HDC News and Top Fruit Update and through joint EMRA/HDC grower days.

Benefits to industry:

Apple canker is one of the most challenging disease problems facing the apple industry, mainly because of the difficulties in achieving successful control. Most of the established apple cultivars are very susceptible to the disease and the more recently introduced cultivars such as Jazz, Braeburn, Reuben, Cameo, Kanzi and Zari are also particularly susceptible. Apple canker can be particularly damaging in young orchards where, in some years, up to 10% of trees can be lost annually, in the first few years of orchard establishment, as a result of trunk cankers, particularly following exceptionally wet or cold winters. Nectria also causes a fruit rot that can result in significant losses as high as 10% or more in stored fruit. Rots often occur in the stalk end of the fruit and are difficult to detect during fruit grading and subsequently develop during marketing leading to the rejection of fruit consignments. Effective products available for use in the growing season are limited. This project would identify new products that could be used in the growing season to protect fruit and the tree from Nectria infection. This should result in better control of the disease and reduction in losses in the orchard and in store.

Aims and objectives:

(i) Project aim and objective: