11 December 1998

Spray tax cuts rate

DENMARKS 25% tax on pesticides has prompted growers to use substantially lower rates.

For cereal growers, at least, that has not resulted in lower profits.

Trials at the Danish Institute of Agricultural Sciences show 25-50% rates are more cost-effective, even though they give inferior disease control, particularly of mildew, Denmarks most troublesome disease.

"We are interested in the most profitable use of fungicides and that does not mean the 100% control of disease," says DIASs Lise Jorgensen.

In the trials the efficacy of various rates of two or three doses of straight strobilurins and their mixtures with triazoles or morpholines were compared with full-rate Glint (propiconazole plus fenpropimorph). For 10 years this product has been Denmarks top cereal fungicide, currently taking over 90% of the market.

"We lack the newer triazoles because they tend to be more persistent than the older ones," says Mrs Jorgensen. "We hope to get epoxiconazole registered but it is questionable whether we will."

Half rates of all six strobilurin and mixture programmes gave better disease control and yield responses than full rate Glint. Best of the bunch was Landmark (kresoxim-methyl + epoxiconazole).

"The higher cost of the strobilurins reduced their economic benefit considerably, so their full rates failed to give the most economic responses," says Mrs Jorgensen. "The best financial returns were achieved with the 50% and 25% rates, but the differences between these were often marginal."

Amistar (azoxystrobin) was registered in Denmark this year and growers hope kresoxim-methyl will be added soon. &#42