Super strain of take-all shows resistance

28 June 2001

Super strain of take-all shows resistance

By Tom Allen-Stevens

DOUBTS have been cast over the effectiveness of the new seed treatment Latitude (silthiofam) after it emerged a strain of take-all may be resistant to it.

Research conducted by IACR-Long Ashton, has identified the field strain of the disease which has reduced sensitivity to Monsantos new active ingredient.

In the Long Ashton trials three strains of take-all G. gramimis were treated with silthiofam to determine the mode of action of the fungicide.

Two of the strains, coded DK22A and T7, were highly sensitive, whilst a third strain UK22A-1 exhibited lower sensitivity to the treatment.

The Long Ashton research scientists estimated the difference in sensitivity as 10,000 fold.

Colleagues at IACR Rothamsted report there is no evidence of take-all resistance to Jockey (fluquinconazole + prochloraz), however.

“UK wheat growers can remain confident in Jockeys ability to protect crops from take-all,” says Paul Cavell, Aventis development manager for seed treatments.

Jockey, launched last year, was the first take-all seed treatment to be approved for use in the UK, while Latitude was launched on 7 June this year.

Generally speaking, Latitude is believed to have the edge on take-all control alone, while Jockey is credited with some foliar disease activity as well.

The Long Ashton research was published at the 2000 Brighton Crop Protection Conference.

Take-all is a soil borne fungal disease which costs UK cereal growers anything from 16 million to 55m each year.


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