Incidence and losses due to fungal rots in cold-stored apples in the UK

Abstract: Fungal rots can result in significant losses in stored apples, particularly in fruit storedbeyond January. Successful control of storage rots depends on a clear understanding of the rots tobe controlled. The objective of this work was to evaluate rot incidence and to assess the successof the current rot control strategy on commercial farms. Seven pack houses, located in Kent, werevisited weekly from January-March in 2009, 2010 and 2011. Visits were also made to apackhouse in Hereford. At each visit at least 100 rotted fruit were removed from the rot bin orcollected from the grader of fruit that was being graded at the time of the visit. Rots wereidentified visually and numbers recorded. In the survey actual losses due to rots were relativelylow (less than 2% losses overall, range < 0.5-5) in Cox compared to the previous survey in 1995-2000. Losses in the newer dessert apple cultivars Gala, Jazz and Braeburn were exceptionallylow. Highest losses were recorded in Bramley (on average 1.8%, range < 1-4%), particularly inthe later stored sample assessed in August. Brown rot (Monilinia fructigena) was still one of themost important rots present. Nectria rot was also causing significant losses. Other rots such asColletotrichum sp., Fusarium sp., Botryosphaeria and Phomopsis, present at trace incidence in1995-2000 survey, have increased in incidence especially on Bramley. Much of the Fusarium roton Bramley was associated with core rot. The incidence of Phytophthora rot was higher in 2011,particularly in the later picked cultivars Jazz and Braeburn, due to above average rainfall fromAugust – October 2010. The incidence of Gloeosporium in apple samples appears to beincreasing, particularly in the newer dessert cultivars, although actual losses remain low.