Opt for correct fungicides to limit your overspending
Know best chemical application rates to ensure you maximise yields and avoid hefty outgoings
Published 19/04/2011 | 05:00
There is little point in applying an input if it does not give a financial return. For most inputs, there isn't a straight-line relationship between the application of the input and yield.
For instance, the yields obtained from nitrogen application on wheat are almost a straight line up to around 50-60kg of nitrogen then the yield starts to level off as the nitrogen levels increase. Yields can also drop off if excessive nitrogen is applied. The trick as a farmer is to apply enough product to maximise yields without over spending. Fungicides are the last major inputs spend on cereals and, perhaps, because it is the last purchase, growers tend to give out most about its cost.
Fungicides are an input, which, on average, give a return on investment of 2-3 times their cost. In some circumstances, there may be little or no return (where crops are clean and disease is not active) in contrast to a return of 5-6 times their cost in a high disease situation.
In most instances, a little insurance is built into the application rate to guard against weather turning for the worst or a delay with the next fungicide application. The extra 'insurance' rate applied is difficult to get right at the time of application and the grower will only know if the application rate was correct with the benefit of hindsight as it is generally dictated by the intervening weather. However, as growers are aware, disease control, especially in wheat, is changing, whereby growers must be more careful of their product choice to ensure good disease control.
New chemistry and products
Venture is well known to all wheat growers and contains Opus plus Boscalid. Boscalid, Bixofen and Isopyrazam are classed as SDHI-type fungicides that are all on the market this year. SDHI fungicides are single-site inhibitors and, as such, are prone to a quick build up of resistant pathogens if used incorrectly. SDHI are only offered in mixtures with triazoles so far. Yield results from trials show SDHI fungicides will improve yield in wheat and barley over the current triazole fungicides.
Bontima contains Cyprodinal, and isopyrazam was introduced in the middle of the season last year and is only cleared for barley. Aviator and Siltra are new to the market this year and contain prothioconazole and bixofen. Aviator can be used on wheat only and Siltra can be used in barley and oats only.
Selecting the correct fungicide