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Home / News / Mind the gap, when it comes to fungicide treatments
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Mind the gap, when it comes to fungicide treatments
Date added: 16/04/10 |
Growers should make sure they ‘mind the gap’ between their T0 and TI sprays this year to make sure that diseases such as Septoria and rusts do not become established, warns Dr. David Ellerton of ProCam UK Ltd.
There is still time to apply a T0 fungicide in many crops and growers should try to get this on where possible, he says.
“Without a T0 treatment, T1 timing can be compromised and rusts and Septoria can romp away. A robust T0 treatment also allows more leeway to apply T1 treatments at the right time.”
If you don’t start off early enough, there could be a domino effect across the whole disease control programme and you will be playing catch-up throughout, he adds.
A T1 spray is applied to protect the top 3 leaves from a number of diseases including Septoria, rusts, mildew as well as protecting the whole plant from stem-based diseases such as eyespot, Fusarium and Take-all.
Dr Ellerton advises that T1 sprays should be applied at GS 32 with leaf 3 fully emerged.
“This is normally three to four weeks after the T0 treatment. But even if you applied your T0 late or not at all, stick with the right target timing for TI.
“It may even be worthwhile dissecting out the wheat plant to get a more accurate understanding of this crucial growth stage. It can be a little finicky, but it’s worth it!”
Wheat crops have greened up well, but are not yet rocketing away, unlike the oilseed rape crops, Dr. Ellerton says.
“Once the weather warms up, crops take up Nitrogen and soils start to dry out a little, they will start to motor. And you need to be ready to put on your fungicides.”
A lot of Septoria in wheat and yellow rust is also starting to build now. In some crops of Oakley you can see foci of infection and in the worse fields a layer of rust spores on the soil surface, he adds.
T1 treatments should be based on the strongest triazoles, epoxiconazole (Opus or Bassoon) or prothioconazole (Proline) alone or in co-formulation, but applied at the minimum of 50% and preferably 75% dose rate.
“You should build your treatments around these robust triazoles and then add in other components according to disease risk. For example, if yellow rust is a threat add in a curative such as tebuconazole (as in Toledo) or cyproconazole (Menara).
“I might also add in some chlorothalonil for extra persistence particularly where none was applied at T0.”
If eyespot is a problem or if growing second wheats, an eyespot-specific component such as prochloraz or boscalid (as in Tracker) should be added in, Dr. Ellerton says.
“Prochloraz helps reduce Fusarium and may reduce the selection pressure on some mutated Septoria strains. Similarly, if mildew is a problem, add in a mildew-specific such as Talius (proquinazid) that offers protection or ideally Cyflamid (cyflufenamid) that has curative and protectant activity.
“A good all-in-one choice for T1 would be Capalo or Cello. Capalo contains epoxiconazole which offers a strong Septoria element plus protectant rust activity, fenpropimorph for rusts, mildew and some Septoria activity with a different mode of action and metrafenone which brings in eyespot, mildew with some Septoria, too.”
Cello contains prothioconazole, tebuconazole and spiroxamine that helps uptake of the trazoles and does a good job across all diseases at T1 including eyespot and Fusarium. |
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