21 March 1997

Competition gets hotter

CONSIDER higher weed populations and the effect of greater crop competition when chosing herbicide rates this spring, visitors to the Weeds in Focus event at ADAS Drayton were advised.

"Cold weather last autumn reduced germination of weeds and as weather now starts to warm up we could begin to see higher weed populations," says Jim Orson of ADAS Boxworth.

That isnt the only consideration this season. Crop density and competition will become very significant factors that may also affect dose rates, he adds.

"There are some weeds that can be controlled by competition alone. For example, knotgrass in a thick crop will die anyway. And there are some products that are more dependent on competition to perform efficiently," explains Mr Orson.

"The level of crop competition and type of weed presence can affect doses by as much as two to three times, which makes herbicide and rate choices very important decisions this season."n