New barley treatment would pay

Press, 26 August 1977, Page 14

New barley treatment would pay

It seems that treatment of barley seed with either of two new fungicides will result in very payable yield increases.

Mr B. J. Arnst, of the Plant Diseases Division of the Department of Scientific and Industrial Research at Lincoln, says

that during the last three years research has been carried out on a, barley disease called net' blotch, which has become widespread throughout New Zealand following the abolition of mercurial seed dressings. The disease is seed borne, although reinfection of plants by airborne spores occurs. The current barley seed treatment is Captan but this fungicide does not control net blotch. But following research on the effect of control of the disease on barley yields, two new fungicides are being recommended for seed treatment. These are “Vitaflo” 200 and “Granosan" 200. Both are commercially available. While both give good control of net blotch, Mr Arnst says that “Vitaflo” 200 also controls loose smut of barley, although this is a disease of minor

importance as only trace amounts are found throughout New Zealand. Mr Arnst has looked at the economics of changing

the current barley seed treatment and these are his findings. The average sowing rate of barley is 120 kg per ha. The cost of “Vitaflo” 200 application is $2.40 per ha and of “Granosan” 200 $2.20. The average yield of barley- is 3.5 tonnes per ha. The monetary return for feed barley is $3Ol per ha and for malting barley $367.50 per ha. Therefore the increase in yield needed to recover the cost of treatment would be: For “Vitaflo,” 0.8 per cent for feed barley, which is 28kg, and 0.7 per cent for malting, which is 24.5 kg. For “Granosan,” 0.7 per cent for feed barley, which is 24.5 kg, and 0.6 per cent for malting, which is 21kg. From trial results the range of yield increases have been: Palmerston

North, 5 to 15 per cent; Wairarapa, 5 to 10 per cent; Nelson, 5 to 11 per cent; Lincoln, 5 to 10 per cent. Therefore, Mr Arnst says that a 5 to 10 per cent increase in yield is likely.

This would give a net monetary return from treatment, with the cost of treatment deducted, as follows:

“Vitaflo”: feed, $12.65 to $28.60 per ha; malting. $l6 to $34.30. “Granosan”: feed, $12.85 to $27.80; malting, $16.15 to $34.50. “As you can see, these returns far outweigh the cost of treatment,” says Mr Arnst. “It should be noted that the yield increases obtained were gained with only about 50 per cent control of the disease. Widespread seed treatment, which would eradicate any windborne inoculum, should provide yield increases of 20 to 30 per cent, especially in the North Island and Marlborough regions. In Canterbury, where net blotch increase is lighter, smaller yield increases would be obtained, but after all anything greater than a 1 per cent yield increase gives a greater return to the farmer.”