Whole-field spray hits thistles

20 March 1998

Whole-field spray hits thistles

THISTLES in grass can now be controlled by spraying the whole field, rather than having to spot treat, using the herbicide Lonpar, launched by Dow AgroSciences last week.

The companys James Knight says this is the first product designed to control thistles in grass by a single full field application or in a programmed approach to give consistent, long-term control. In the past thistles have mainly be controlled by spot treatments.

Thistles cost UK grassland farmers about £32m a year, with 400,000ha (1000,000 acres) having a thistle population of more than 10%. "Just two shoots a sq m results in a 15% loss in grass yield."

Losses occur through competition for minerals and are valued at £100-£120/ha (£40-£49/acre). Animals avoid grazing close to thistles, leaving valuable grass around them to deteriorate in quality.

A single dose of four litres/ha (1.6/acre) of Lonpar or two doses of two litres/ha (0.8/acre) in spring and autumn costs £28.70/ha (£11.60/acre).

The spray works into the root structure and younger leaves of plants, reducing the number of growing points for the next season.

The best time to spray is when thistles are in the green rosette stage, said Dow AgroSciences Corinne Horne.

Livestock can graze Lonpar sprayed fields after seven days, and grass can be cut 28 days after spraying. &#42

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