15 June 2001

Newcomers hot up this mid-seasons blight spray market

By Andrew Swallow

MID-SEASON blight spray markets seem set to be especially competitive with the launch of three new products.

Electis (zoxium + mancozeb), Ranman (cyazofamid) and Tanos (famoxate + cymoxanil) from Interfarm, BASF and Du Pont respectively join current mainstays such as Shirlan (fluazinam), Invader (dimethomorph + mancozeb), and Curzate (cymoxanil + mancozeb).

According to one leading distributor who has had access to all three new products growers can look forward to a significant advance in control.

"Historically, in blight trials, most new products have been broadly similar in terms of efficacy," says Agrovistas non-combinables technical manager John Keer. "That is until last year when we had Ranman and Electis. These two products were clearly ahead of the field."

Prices have also been set competitively. But growers should not switch into them wholesale, he warns.

"I would use them in a programme with Curzate, certainly alternating two products, possibly all three," he says.

With both Ranman and Electis offering a good level of tuber blight control continuing with them after Curzate makes sense, he continues.

"With the likely review of tin in the next couple of years we have to start looking at other products for tuber blight control."

Early applications of Shirlan (fluazinam), at the rosette stage or 15-20% ground cover, also aid tuber blight control, he says.

"Really you are spraying the soil, not the foliage, with the aim of stopping zoospores spreading and infecting tubers."

But mid-season is where the new products come into their own, with Ranman in particular standing out for foliar blight control.

"It was head and shoulders above the rest."

Some evidence of prolonged greening and yield increase beyond disease control, as with cereal strobilurins, was seen. But Dr Keer stresses that it is only one seasons work and results need to be proven.

As a strobilurin-type active Ranmans edge will need protecting from resistance, especially as it is a straight formulation. BASFs advice to alternate applications in sequence should be heeded, he says.

"We know strobilurins have broken down to diseases with a rapid life cycle such as mildew. In resistance build-up terms, blight is far more dangerous."

Tanos (famoxate + cymoxanil), while not bringing the same advance in efficacy as the other two new blight actives, does have a place early in the programme thanks to its high rate of cymoxanil.

"It seems to have a good kick-back effect on stem blight, which could be especially useful on early infections derived from seed."

While not a new active, Sipcams C50 (cymoxanil) is the first stand-alone cymoxanil formulation which could also be useful for increasing kickback, he says.

lAnother strobilurin potato blight product is in the pipeline from Aventis. Subject to PSD approval, fenamidone mixed with mancozeb will be available next season. &#42

BLIGHT BONANZA

&#8226 Three new actives.

&#8226 Useful new formulation.

&#8226 Step up on standards.

&#8226 Use in sequences.