Co-formulation adds ‘spray day’ flexibility to cleavers control this spring

UK - January 26, 2010



With an ever-increasing number of extreme weather patterns playing havoc with agronomists' and growers' spray programmes in recent seasons, making the most of available spray days this spring could be the difference between success or failure in the fast-approaching broad-leaved weed control campaign.

Following variable levels of pre-emergence herbicide broad-leaved weed control last autumn, mainly due to dry seedbeds, it is thought that cleavers and other broad-leaved weeds are likely to have fared well in those conditions and will pose an increased threat this spring.

"This will make it even more important that cereal growers make the most of the available spray days," emphasises Stuart Jackson, Dow AgroSciences agronomist. "Cleavers is the most competitive weed in cereals, and even one plant per square metre can lead to as much as a three per cent yield loss. They should therefore be taken out early in the season, before GS32, to prevent significant yield losses later on."

The mean of four years of trials carried out by Dow to investigate cleavers control between growth stages 30 to 39, suggests that a loss of 2.2 tonnes per hectare can be expected in winter wheat by sticking with later weed control programmes.

"We're definitely seeing a yield benefit by attacking cleavers early," continues Mr Jackson. "Early season applications before GS32 consistently produce a better yield and subsequent margin-over-input than a late-season application. From GS32 onwards cleavers really start to compete with the crop and this is when we see the yield beginning to drop off if they are left untreated until the later timing."

According to Mr Jackson Dow research, based on soil temperatures and taking the last five years as an example, has shown that a mean of 24 extra spray days could have been utilised during March, April and May, by applying co-formulated herbicide Starane XL (florasulam + fluroxypyr) for the control of cleavers, compared with its fluroxypyr-only stable-mate Starane 2.

"Starane XL, with its co-formulation containing florasulam, will provide robust control independent of the temperature or speed of cleavers growth at application, offering farmers increased flexibility compared with the straight fluroxypyr in Starane 2. Cold weather or frosts therefore present no application issues, as long as the cleavers are showing growth."

Mr Jackson points out that Starane XL is ideally included at 1.25l/ha in a T1 tank mix "when the sprayer is in the field anyway, ensuring that cleavers are controlled before they compete with the crop at GS32 onwards. It also offers control of a wider range of broad-leaved weeds than fluroxypyr on its own and is very compatible with fungicides."

 According to Mr Jackson, Starane 2 is more suited as a "late rescue" treatment if earlier broad-leaved weed control applications were missed, or where the allowance for ALS inhibitors has been used up, preventing the use of florasulam in the programme.

"Looking ahead to the spring, Starane XL will give agronomists more even management flexibility during the season with more spray days available," says Mr Jackson. "The co-formulation is ideal for those farms with a threat of cleavers and with big acreages to cover. The extra spray days can be utilised, resulting in greater management flexibility for the grower and a potential yield benefit through good weed control."