Blight research

Each year there is something new learned about potato blight (P. infestans).

A stand-out take-home message from 2017 is that from 2018 onwards greater attention needs to be given to managing the threat of fungicide insensitivity.

Insensitivity is the term used in fungicides to describe loss of effectiveness.

Growers effectively lost one highly active fungicide, metalaxyl-M, to insensitivity in the mid-2000s.

There is now a very serious threat to fluazinam and Scotland’s Rural College (SRUC) warns that greater attention needs to be paid to fungicide modes of action, or FRAC codes, when choosing products for programmes to help prolong the life of fungicide active ingredients in the long term.

SRUC states that avoiding prolonged selection pressure from any one fungicide mode of action (MoA) is necessary, which means ringing the changes in terms of FRAC codes throughout the fungicide programme.

The advice adds: “Although there are 13 of these available to help control disease, there is no room for complacency.

“This is because fungicide usage is dominated by a restricted number of FRAC codes.

“Also, in the absence of fluazinam, there are only two modes of action that can provide very good control of tuber blight and they are expected to come under increased pressure.”

Late blight: SRUC warns that greater attention has to be paid to FRAC codes.