Disease monitoring (Apple canker)

Canker

  • Inspect orchards in late June for shoot dieback, and during winter pruning for larger cankers.
  • Assessment of Neonectria rots (i.e. eye, stalk and cheek rots), during grading, in fruit stored post Christmas, will also give an estimate of the canker problem in the orchard.

Fruit rot

The risk of Neonectria fruit rot in store can be estimated pre-harvest, based on the incidence of cankered trees in the orchard, the rot history taken from packhouse records and the rainfall between blossom and harvest.

Inspect orchards in the spring for cankered trees and estimate the % cankered trees.

Canker incidence (% cankered trees) Risk
No canker no risk
<5% low
5-25% moderate
>25% high
  • In orchards with more than 5% of trees with canker, where long term storage of the fruit is planned, apply fungicide sprays for control of Neonectria fruit rot during blossom and at petal fall.
  • Monitor rainfall from blossom to harvest
  • Decisions on the need for early marketing of fruit can be made as follows:

Orchard canker risk

Orchard canker risk Rain Blossom - harvest Action
High <average Market fruit pre-Christmas if no sprays applied in blossom
average
>average
Moderate <average Low risk, No special action needed
average Market pre-Christmas if no sprays applied in blossom
>average
Low <average Low risk, No special action needed
average
>average Market pre-Christmas if no sprays applied in blossom