Pigeons pose resistance questions

11 July 1997

Pigeons pose resistance questions

GROWING novel herbicide-resistant crops may not be as straightforward as first thought, according to Andrew McShane of distributor &#42 L Hutchinson.

Pigeons have found genetically modified Liberty Link spring rape much more tasty than conventional variety Marinka in a trial at Wisbech.

The new variety, designed by AgrEvo to resist the broad-spectrum weed-killer glufosinate-ammonium (as in Challenge), is expected to be marketed next year.

"It is a lot more susceptible to pigeon damage than Marinka," says Mr McShane. "It shows that we have got to watch the whole package."

The fact that the Marinka plots have partially withstood Challenge sprays confuses the picture further, he adds. The high number of plants remaining suggests that they cannot all be volunteers.

Two doses of Challenge, at 1.5 and 3 litres/ha, were applied to both crops, the higher rate hitting the pigeon-damaged plot to leave a thin stand. By contrast an application of Butisan S (metazachlor) seems to have deterred the pests.

"Growing these crops will be a lot more complicated than we anticipated," says Mr McShane. &#42

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