28 August 1998

Isoproturon alternative on the market

A NEW formulation, low-cost autumn herbicide is available from manufacturer Cyanamid.

Activus contains pendimethalin and cyanazine, as in break-crop product Bullet. Rapid control of broad-leaved weeds and both annual and rough stalked meadow grass means it is being promoted as an isoproturon alternative for sites without blackgrass or wild oats.

"Cyanazine is highly soluble, so it works very quickly," says product manager Rob King. It also works in dry conditions, as the cyanazine rate is high enough for contact activity, he adds.

Residual activity comes from the relatively insoluble pendimethalin "There is little chemical movement in the soil, even after heavy rain, so residual activity is quite persistent."

At 2 litres/ha, the recommended rate delivers 300g of cyanazine and 528g of pendimethalin, and will be priced at £13.50/ha.

"It is a pretty good all-rounder and at that price it will be fairly competitive," says Scottish Agro-nomys Andrew Gillchrist, who trailed the product last season.

Winter wheat timing is from one to two leaves to before tillering, and throughout tillering in barley. Any manganese deficiency should be corrected before application, to avoid the risk of crop damage. There is no buffer-zone requirement.

Over 90% control is claimed for volunteer rape, mayweed, poppy, chickweed, pansy, groundsel and annual meadow grass, with some activity against cleavers. &#42