English apple growers hit with the loss of post-harvest dipping chemical carbendizum could benefit from joint work carried out last season by Bayer CropScience and East Malling Research.
Bayer has developed its Elvaron Multi pre-harvest treatment in an attempt to reduce both the need for post-harvest dipping and the residue potential that it says this creates. Tolylfluanid, the active ingredient in Elvaron Multi, works against post-harvest rots when the product is applied two to three weeks before picking.
With carbendizum banned from this year, growers’ post-harvest options have been reduced. The early picking season has been disrupted by rainfall across the country and the incidence of rotting is likely to be relatively high.
Bayer’s work with EMR’s Angela Berry last year could therefore prove timely. “We worked with Angela to develop the recommendation for storage rots but we were also aware of the pressure that growers are under to reduce residues. Therefore, as well as checking efficacy we also investigated residues of tolylfluanid on apples as they entered the store and as they were removed,” said Bayer’s Stephen Humphreys.
The analysis showed that residues were below the Pesticide Residues Committee’s testing level of 0.05mg/kg, which is two orders of magnitude away from the Codex Maximum Residue Level of 5mg/kg. “The efficacy was fine and there were no detectable residues at the 0.05 mg/kg level when the apples entered the store and when samples were removed in mid-January, mid-February and mid-March,” said Humphreys. “We’re hopeful that this product will be more widely used this season. The Food Standards Agency’s draft guidelines on residue minimisation in apples suggest Elvaron Multi as a potential tool for reducing residues from storage rot products.”
Good crop hygiene, such as pruning out cankers and removing low-hanging branches, should also be employed in order to minimise the potential of storage rots, he added. “Such activities can however leave trees susceptible to infection, but earlier this year Bayer CropScience introduced the new product Bezel, the only registered wound paint in the UK.
“Bezel is a paste formulation containing the fungicide tebuconazole and can be applied to the cut wound following pruning in apples and a wide range of other trees. The product dries to form a tough seal and has excellent activity on canker and silver leaf, thereby protecting the tree from infection,” said Humphreys.
