26 October 2001

Garlic spray all set to beat ban on OPs

AS pressure against organo- phosphate insecticides grows a novel garlic-based product could help brassica growers combat insect pests.

OP products Birlane (chlorfenvinphos) and Yaltox (carbofuran) may not be used after Dec 31. But garlic-based ECOguard could offer an effective, although more costly, alternative.

Large-scale swede supplier and grower Kim Drysdale is alarmed at the prospect of a ban on OPs and has been lobbying to get them reinstated.

But he has also been using ECOguard at R & K Drysdale Farms, Cockburnspath, near Berwick, Northumberland, for three seasons and believes it could help combat pests if OP approvals are not reinstated.

Mr Drysdale has used ECOguard to control cabbage root-fly on his 11ha (28 acres) of organic swedes. Growing pessimism about the future of OPs persuaded him to try the product on part of his 580ha (1400-acre) commercial crop.

"Combined with insect trapping ECOguard is acceptable as the second best option to Birlane for controlling cabbage root fly," he says. "My feeling is, it is not quite as effective, but I have no proof of that. It is also more expensive. But if the OPs are banned, growers like myself will have little option but to find something else. That leaves me with two choices – either applying ECOguard or using a crop cover."

Although covers are more effective, they are highly labour-intensive and involve a large capital outlay, Mr Drysdale notes.

Yaltox is currently the main form of defence against first generation cabbage root fly in mainly Magres and Helenor swedes, followed later in the season with Birlane, which acts against the second and third generation root fly.

"The ECOguard granules are designed to replace Yaltox at drilling, although in some seasons a further application may be needed at the scarifying stage," says Mr Drysdale.

"The rates and timing for the liquid form of the product are dependent on when the pests appear, but it is usually put on every 10-12 days starting at the end of July and finishing around the first week in September."

ECOspray sales manager, Stephen Silvester, stresses that although ECOguard is sold as a plant nutrient, it is still awaiting approval from the PSD (Pesticide Safety Directorate).

"Even if Birlane is reinstated, the EU is looking to withdraw all organo-phosphates by 2003. That will mean a greater demand for an alternative method of brassica pest control," he predicts.

"Supermarkets are already pressing farmers for OP-free foods and there are few alternatives which really tackle insect pests. Our trials have shown ECOguard to be effective against cabbage root fly and carrot fly. It works by killing the eggs and larvae and repelling and killing some adult insects. We are also looking at using it on other pests such as aphid, thrip, free-living nematodes and slugs."

In liquid form ECOguard is a pure form of concentrated garlic, while the granules contain a 45% garlic concentrate. Mr Silvester is quick to point out that the garlic does not affect the quality of the vegetable and says any odour or taste disappears within 24-48 hours of application.

Recommended rates are flexible, but the usual advice is to apply 2-4litres/ha of the liquid and about 12kg/ha of the granules, depending on conditions.

As the product is high in sulphur and nitrogen, it is also claimed to deliver growth benefits as well as protecting the plant from insect attack. &#42

Retailer thumbs up

One of Mr Drysdales biggest customers is the Co-op supermarket chain. Quality assurance manager, Kevin Barker says his company has already banned the use of chlorfenvinphos on its fresh produce and will welcome the use of ECOguard once it is approved.

But he will not be drawn on how much more the Co-op will pay for farm produce to compensate for possible increased grower costs if OPs are banned.

"We will have to take into consideration the extra expense of using alternative products," he says. "As a retail business which is also heavily involved in farming, we are sympathetic to growers and our buyers department is already discussing this issue with the suppliers."

Cost comparison1 (£/ha)


Yaltox 70

Birlane 120

ECOguard granules 162

ECOguard liquid 220

Crop cover (Environmesh) 1202

Yaltox + Birlane 190

ECOguard granules + liquid 382

1 Excluding application costs.

2 Based on an estimated £600/ha spread over five years.

BIRLANE REPLACER

&#8226 Approved use of Birlane ends Dec 31.

&#8226 ECOguard – garlic-based.

&#8226 Liquid and granular formulations.

&#8226 Multi-site action – ovicidal, larvicidal and repellent.

&#8226 Currently sold as plant nutrient.

&#8226 Awaiting PSD registration.

Garlic-based ECOguard looks a useful stand-in for when OP insecticides are banned in leafy brassicas, says Northumberland grower Kim Drysdale.