Resistance unlikely

21 March 1997

Resistance unlikely

RESISTANCE to herbicides in wild oats is rare but should not be forgotten, says Mr Talbot. "There are cases, but I believe the risk of it developing is much less than with blackgrass because oats are self-pollinating and seed numbers are lower. The general view is that it is unlikely to escalate as fast as with blackgrass." &#42

For commercial reasons Profarma does not supply Zenecas Grasp (tralkoxydim) which can be used up to GS31 (first node detectable) of wild oats in both wheat and barley. Different rates for spraying autumn- and spring-sown cereals, 1.4 and 1 litre/ha, respectively, reflect likely size of the weeds and expected growing conditions, says a Zeneca spokesman.

Key to its use is the correct adjuvant, Output, he stresses. Other additives have caused flocculation and efficacy problems. Growers hoping to cut dose rates must take specific field advice, he advises. "The only way to trim rates is in very good growing conditions with the smallest weeds."

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