Emergency authorisation has been issued for Certis’ fungicide Cuprokylt, for use against Nectria canker in apples and pears.
This has come as a welcome relief to growers and agronomists alike, as the number of active ingredients for use against Nectria canker is limited, explains Hutchinson’s horticultural agronomist, Rob Saunders.
“The climate in the UK means that our orchards experience high canker infection pressure, and the newer varieties like Gala and Kanzi have little resistance to the disease. Cuprokylt is a very important product that protects new infection entry points at key times in the season,” says Rob. “Nectria canker can be particularly damaging in young orchards, as when a canker lesion is present in the central stem it results in the loss of the tree. Some young orchards have suffered losses of up to 10% per year,” he adds.
There are two key periods when canker infections can become established, firstly in early spring during bud-break where bud scales fall, leaving a scar, and secondly, the most significant period is during leaf fall in the autumn, when falling leaves result in thousands of leaf scars. These scars are not easily infected, but because they are so numerous, they are the most significant entry points for new canker infections – ranking above both fruit picking scars and pruning wounds in importance. “Being able to apply Cuprokylt onto these entry points is really important for reducing the possibility of a new canker infection taking hold,” says Rob Saunders.
Cuprokylt is a protectant fungicide, containing 50% w/w copper oxychloride, in a wettable powder formulation. It has a multi-site mode of action and is classified by FRAC as ‘low-risk’ for the development of fungicide resistance. It should be applied at a maximum individual dose of 2 kg/ha with a maximum of four applications in a minimum of 400 litres/ha water volume, though higher water volumes and the use of a wetter are likely to be beneficial, as good cover is vital. The latest time for this application is before bud-burst or growth stage BBCH07 with a minimum of seven days between applications. Application should be made using an air-assisted broadcast sprayer.
The emergency authorisation will last for 120 days and will expire on 14 July 2017. There is a 50m aquatic buffer zone that must be strictly adhered to.