As if the fact that summer is yet to materialise isn’t depressing enough, potatoes have something else to contend with. Experts say that the current period of cool and wet weather not only favours the production of foliar blight but also offers ideal conditions for the production of zoospores, the causal agent of tuber blight.
The BPC has been waging an ongoing campaign for growers to keep aware of blight this season, with plant pathologists having found that zoospores are produced at lower temperatures of 10-15C, which is why they are normally more common in the early part of the season and towards the latter part of the growing season.
According to principal biologist for Dow AgroSciences, Andy Leader, growers cannot rely entirely on foliar blight control to prevent tuber blight, especially this year. He says that the crop foliage must be thoroughly protected by robust blight fungicides that also have proven zoospore activity.
“Spray intervals need to be kept tight and the programme should continue right up to and beyond dessication. Once tubers start to form they are at risk from tuber blight. You only need a few zoospores to reach potato tubers to suffer significant and damaging blight infections.”
Leader advocates the use of zoxium in Electis, which he says stops zoospore formulation and release, resulting in the production of non-motile spores, incapable of infecting tubers. Using the product to reduce the zoospore loading as early as possible, Electis can optimise the activity of other fungicides that have more direct zoospore activity, he added.
No comments yet