29 September 2000

Call for more info on spray labels

By John Allan

LABELS on many established agrochemicals and most new ones advising a medium quality spray at an application rate of 200 litres/ha need urgent attention, according to one Cambs grower.

"Such recommendations pose problems to the sprayer operator unless off-label information is available," says Andrew Howesman, farm business manager for HS&D Burgess at Yaxley, near Peterborough.

The overriding need is for a spray quality that gives optimum and even retention on the target, while minimising the risk of spray drifting away from the intended area, he says.

But target requirements can conflict. "For example, you often need to get a fungicide on the upper part of a plant but the herbicide in the tank mix has to penetrate to reach the weeds. That is where the droplet mix in the old faithful F110-04 nozzle working at 3 bar and about 8kph stood farming in good stead over the years."

The company recently invested £87,000 in a direct injection sprayer, which has improved work rate, flexibility and results on mixed arable and vegetable cropping grown to LEAF ICM standards.

But it has also highlighted the need for adequate operator training when a new spray system or nozzle type is introduced, says Mr Howesman.

He is keen for manufacturers and researchers to provide more guidance. "So far we farmers have had to evaluate new nozzles in our day-to-day work, often because we can see benefits in them."

A host of factors are challenging the label recommendation of 200 litres/ha medium quality spray (see box). "It may have been OK before, but is it good enough when environmental and financial control are so critical?" asks Mr Howesman.

For example, the standard label wording takes no account of the larger drops from air inclusion bubble jets. Neither does it consider the higher speed that many sprayer operators use today.

Targeting the use of twin outlet nozzles and the ability to change spray quality on the move with air injection nozzles also need clarification, he says.

Interested parties need to get together to make sure the full benefits of new technology are realised, he says. "This is also needed for truly integrated crop management." &#42

SPRAYQUALITY

&#8226 Most agrochemical labels advise 220 litres/ha with medium quality spray.

&#8226 Many factors affect application quality and results.

&#8226 New generation nozzles and equipment usually validated by on farm use.

&#8226 Operator training essential for new techniques.

Andrew Howesman says not all spray labels give the info operators need to optimise applications.

SPRAYQUALITYISSUES

&#8226 LERAPs.

&#8226 Green Code requirement that spray shall not fall outside the target area.

&#8226 Need to achieve even applications of only 20-30g over 10,000sq m.

&#8226 Extra spray days achieved with larger droplets produced by air induction nozzles.

&#8226 Obtaining medium droplets at high water rates.

&#8226 Increasing application speed.

&#8226 Quality of boom performance.

&#8226 Lower doses.

&#8226 Reduced volumes.