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TO STROB OR NOT TO STROB ?
Date added: 10/02/05 |
Despite growing resistance and falling grain prices, strobilurins and triazoles are still critically important and cost-effective fungicides in UK crop producers’ spray programmes, says ProCam technical director David Ellerton.
“Figures show that resistance of Septoria tritici to strobilurins, increased from 84% to 95% over the last year so our predictions have come true,” Dr. Ellerton explains.
“Septoria is also continuing its shift towards insensitivity to triazoles as well.”
“However, strobilurins are not just about disease control. They have important physiological effects on the plant as well, so their effect is more complex than many growers realise.”
One of the main areas is their ability to keep crops greener for longer improving photosynthesis and ultimately yield. Last year, data showed this effect contributed to treated crops staying green for an extra 4 days - and in most years it’s nearer to 6 days.
“The increase in yield from strobilurin treatment last year was just over 0.4
tonnes/ha. At a wheat price of £50/tonne, we would need to see a yield response of 0.36 tonnes/ha so even at this artificially low price, Strobilurins would still be cost- effective. At a more realistic £60/tonne the necessary response is just 0.3tonnes/ha.”
In addition, all varieties are responding adequately to triazoles, so these still have an important role to play in 2005, Dr Ellerton says. However, dose rates need to be increased in line with the reduction in sensitivity of the Septoria tritici population. |
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