Still the weather is making the headlines. I am somewhat frustrated when I see a certain advert suggesting that potatoes love water. They may well do, but there is a limit, they also love sunshine too and with that in short supply I fear yields and quality will be extremely variable.
Tramlines are now full of water and as deep as they might be at the end of the season, maintaining regular blight spray intervals is proving challenging to say the least. As a consequence I am finding blight in many areas.
The sources of these outbreaks seem to be from the usual culprits, potato dumps, potato volunteers, particularly from around the outside of existing potato fields that haven’t been covered with blight sprays and seed.
Wherever possible I have been sending samples to FERA for confirmation and strain identification. We need to know if the much talked about Green 33 strain is here so that we can manage spray programmes accordingly towards the end of the season.
I recommend aiming to keep spray intervals as close to seven days as possible and the use of Revus (mandipropamid) or Ranman Top (cyazofamid), the most effective two products according to the Euroblight tables, with the addition of cymoxanil, cymoxanil plus mancozeb or cymoxanil plus propamocarb, to enhance kick back activity. I would always advocate the use of alternate facing angled nozzles to further enhance the penetration and effectiveness of all products used.