Large cleavers present easy target for control

8 May 1998

Large cleavers present easy target for control

LARGE cleavers are threatening cereal crops. But they present a big target and growers have powerful products to make an effective kill, say specialists.

If you can see cleavers, youve really got to control them, urges John Garstang of ADAS Boxworth. The mild winter and wet conditions have allowed uncontrolled cleavers to keep up with the crop canopy even in forward situations.

However, big weeds may help growers with their cleaver control. "They are big, but soft. Frosts have not hardened them. They should respond well to sprays and growers can still get product onto the target."

What population of the weed merits control is hard to assess. There are threshold figures, but they can be confusing as the weed tends to occur in patches, he says. In thick crops one single large cleavers plant can induce patch lodging, which then cascades out across the field, he adds.

That view is echoed by Rhett Davies, technical manager for Sands Agricultural Services, Norfolk. "You must get a very high, consistent level of weed control. The minimum 98% control figure is absolutely spot on," he says.

Growers who dont achieve that are storing up problems for future crops, especially potatoes and sugar beet, he maintains.

But dont rush in when the conditions are not fit. Best control is achieved when the weed is growing rapidly, and greater flexibility in dose rates and tank-mixing can cut costs for growers. &#42

So how good is your cleavers control? From left: 100% control is ideal and 98% acceptable. 0% control is obviously unacceptable, but so too is 90% control, warn agronomists.

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