With the spray season approaching, we asked technical adviser David Felce for some advice on T0 best practice. Martin Rickatson reports.
With the spray season approaching, there are a number of pointers which can help with sprayer set up and operation for successful results at the T0 timing, according to David Felce, eastern region technical adviser for Agrii.
He says: “Where crops have been drilled later as part of a black-grass control regime and autumn spraying windows have consequently been much shorter, a well-planned T0 can target weeds that may be present, as well as begin the disease control programme. T0 also has a role to play in more forward crops, where early disease control in lush growth may be required.
“In high pressure seasons particularly, a chlorothalonil-based T0 around the end of March can help protect leaf four from septoria infection. Adding a triazole consistently improves yield at this timing and can also help against rusts. There is also the opportunity, if necessary, to tackle eyespot while the canopy is small.
“At the same time, there is also the option of including an early PGR to aid root development, and trace elements such as manganese and zinc where required. So the T0 application may not be the most critical fungicide timing, but it has many functions.”
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Unless crops are very forward, plants are likely to be short and canopies small at T0, and so, subject to the labels of the products being used, low water rates (such as 100 litres/ha) should be used.
“Thorough leaf coverage is critical, so a medium-quality spray is required, and angling nozzles alternately forwards and downwards can help to cover small canopies effectively. Flat fan nozzles generally do a good job at this stage, but specialist types such as the Defy nozzle can help maximise leaf coverage, as can air induction nozzles producing a relatively small droplet. Guardian Air or Lechler IDKT types with twin outlets are other possibilities for getting products onto all leaf surfaces.
“Keep the boom low – the crop is pretty much still at ground level, so operating at 50cm above the target means it won’t be working any higher than it was at for pre/post-em work. As a guideline, forward speed is best kept to about 12km/hr to minimise drift and maximise spray penetration.”
Before sprayers even leave the sheds, Mr Felce advises ensuring they are ‘dewintered’ ahead of commencing work.
He says: “The machine should have been properly dosed with antifreeze, and this will need to be thoroughly flushed out. Also take into account the last work the sprayer did back in the autumn – in many cases it may well have been applying something like Kerb (propyzamide) to oilseed rape. Even if full washing-out took place and machine hygiene practices were carried out as recommended at the end of that work, flushing things through again ahead of T0 spraying is good practice.”