28 November 1997

Smother savings

CUTS in broad-leaved weed herbicide rates could be possible when more aggressive wheat varieties are grown.

Trials at IACR-Long Ashton showed prostrate, wide-leaved Avalon smothered weeds sprayed with reduced rates of herbicide more effectively than erect, narrow-leaved Spark.

When 100 volunteer oilseed rape plants/sq m were left untreated both varieties suffered a 20% yield loss. However, applying a sixteenth rate of Ally (metsulfuron-methyl) halved Avalons yield loss while Sparks stayed the same.

Further tests showed at least twice the dose was needed in Spark plots to achieve the same level of control achieved in Avalon plots. Similar results are expected with a mix of weed species.