Best practice compared to standard farm practice (Apple canker)

Given how widespread canker is in UK apple orchards and the significant tree and fruit losses it causes every year, AHDB Horticulture funded Project TF 167 to compare the level of control achieved by a best practice control programme compared to a standard programme used by commercial apple growers. The project, led by East Malling Research used two commercial orchard sites, both planted with Gala on M9 rootstock. The effect of a full integrated progamme for canker control on the incidence of new cankers, Neonectria fruit rot and shoot growth, was compared with that of a standard fungicide programme with no addditional specific measures for control of canker.

Standard fungicide programme

• Cuprokylt applied at 10% and 50% leaf fall

Fully integrated programme

Standard fungicide programme + additional sprays for canker at key times as follows:

• 2-3 at bud burst- bloom (protection of bud scale scars and late frost damage)
• Petal fall
• Petal fall + 2-4 weeks (summer leaf fall)
• June/July (fruit thinning)
• August (summer pruning)
• Sprays for fruit rot at bloom and pre-harvest
• Tebuconazole (Fathom) applied pre-leaf fall (October), Cuprokylt at 10% and 90% leaf fall and Fathom at 50% leaf fall

The results of the three year study clearly showed that application of an intensive integrated programme for canker control resulted in a significant reduction in numbers of new cankers and Neonectria fruit rot. However, such an intensive programme is costly and can result in detectable residues in fruit at harvest.