15 March 2002

Add resistance to fungicide plan

BE sure to consider varietal resistance and the weather in March and April before splashing out on relatively expensive wheat fungicide programmes, advises Yorks independent consultant Brian Beeney.

After plenty of early drilling and a mild winter, selling strobilurins this spring will be easier than ever because of perceived high disease pressure, says Mr Beeney, who is a member of the AICC.

But low grain prices and experience over the past four seasons, when several varieties failed to give economic responses to strobilurins, suggests a cheaper triazole-based programme could be just as rewarding, he says. "Many of our crops received just one triazole fungicide last year, which was absolutely justified. And one of my biggest customers has already decided to be very conservative because the price of wheat is so low.

"We shall be looking carefully at the weather in March and April, but the customer cant see the point of spending £15/acre extra above the price of a triazole/chlorthalonil programme.

"Triazoles are always useful as the starting point in any disease control approach. If you must spray at T0 you can use a triazole because a strob is not neccessary at that stage. A relatively low dose of the best products should take care of rusts and suppress septoria."

All other things being equal, epoxiconazole (as in Opus) is widely regarded as the best overall choice, says Mr Beeney. "Fluquinconazole and metconazole are similarly effective, but not significantly cheaper."

For later treatments much depends on disease development during March and April. "If it stays cold and dry septoria wont move on so you can relax a bit."

Last year the only wheat in his local trials giving an economic response to strobilurins was Claire. "I admit it was generally a low disease year, but it certainly makes you think." &#42