6 April 2000        


Rural Media; Farm Pages




Dippy wools face foreign flak

(450 words)

Some New Zealand wool does not comply with proposed European Union environmental standards, according to mid-season results from WoolPro’s annual dip residue survey.

Dip chemicals are washed out of wool during processing, which means they don’t pose a health threat to consumers. Instead, the residues end up in the effluent from wool scours where they become a potential environmental hazard.

"Disposing of dip residues is a problem the European Union can do without," says WoolPro environmental technologist Stuart Edwards.

"For wool to be eligible for entry to high value European markets, residues in wool at shearing will need to be below 5 parts per million (ppm) from 2002 -- only three shearings away."

WoolPro’s Operation Clean Fleece –- launched five years ago --aims to get residues of the three main dip insecticide groups below this target as soon as possible.

"While great progress has been made, a minority of growers still have a problem," Mr Edwards says.

"Half way through our annual residue survey, a quarter of samples bearing organo-phosphates have residues of more than 10 parts per million. These are predominantly fine wools.


"Synthetic pyrethroids are within the limit for 94 per cent of samples tested. Insect growth regulator levels are acceptable for 85 per cent of samples."

It’s not a case of farmers not trying, because we know they are, says Mr Edwards.

"But fine wool growers especially had a mild winter, lush spring growth and a warm, humid summer. Their sheep faced the biggest fly challenge for a number of years."


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Dips 2




"This seems to have prompted some growers to resort to traditional plunge or shower dipping with organo-phosphates in the mistaken belief it is the most effective treatment."

He says organo-phosphates provide only about six weeks’ protection. They are not as cost-effective as insect growth regulators which control flies and lice for twice as long, even in high-challenge seasons, if their administration is timely and thorough.


IGRs applied using hand-jets or modern targeted jetting races are the most cost-effective treatments for flystrike according to Stuart Edwards. Properly applied, they provide about 12 weeks protection.

Pour-on treatments for lice can be equally effective, but only if they are properly applied.

"Ideally, they should be applied along the backbone from the back of the neck to the tail. In practice however, it is difficult to achieve this accurately.

"The sheep react to the application and you end up with a squiggly line down the back of the sheep, leaving parts of the animal untreated," Mr Edwards says.

"We recommend splitting the dose in two and making applications to each side of the backbone. This will ensure better coverage, especially around the high-risk brisket area, and it takes only marginally longer."

He says reducing residues normally requires farmers to make several changes to their farm management practices. There is not a simple solution which applies to every farm.

"WoolPro is keen to help. Farmers who are having trouble with residues and with lice and fly control should get in contact with us on Freephone 0800 4 WOOLPRO."




Farm Editors please note: JPGs of Stuart Edwards and of sheep dipping can be supplied by e-mail on request.