We have today received the report of the sensitivity testing that FERA have been undertaking for us and it makes very interesting reading. Firstly just a quick reminder that these tests were undertaken on isolates from 5 nurseries (2 in Norfolk and 1 each in Lincolnshire, Northern Ireland and Cornwall) using 9 different fungicides. The main headline findings are that all isolates were totally resistant to Metalaxyl M and that no chemical completely controlled the disease.
The best control was obtained from Percos and Paraat but very worryingly, one isolate showed a low sensitivity to both of these products. Revus, Fubol Gold (but only from the Mancozeb) Fenominal and Previcur Energy gave moderate control whereas Ranman and Signum gave almost no control.
This show why we have had such problems with the disease this year and working with specialist agronomists we will now use these results to draw up the best control strategy for next year which will be communicated to growers through both the CFC and AHDB.