Bulletin Volume 171-187 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ...adhesiveness is a desirable quality of copper carbonate, it is not an accurate measure of its effectiveness. 3. An experiment was conducted to determine the comparative effectiveness of different brands of copper carbonate for the prevention of smut from seed-borne spores (spring plantings). Two varieties were used: Jenkins Club and Bluestem, each carrying light, medium and heavy loads of smut, with 2 or 3 oz. per bushel, making twelve plantings for each brand. In 108 tests with 9 brands of pure copper carbonate, the average per cent of smut was 0. 39. In these tests perfect control was obtained in 60. In 48 tests with 4 brands of copper carbonate testing 20% or less of metallic copper there was an average of 1.28% smut. In 48 of these tests perfect control was obtained in 14. In 12 untreated samples, there was an average of 27.5% smut. None of the pure copper carbonates gave perfect control in all of the 12 tests in which each brand was used. The differences for the different brands were so slight that one is not justified in proclaiming the superiority of the product of any particular company. In general the compounds with low copper content were not so effective as the pure copper carbonates. The results obtained in this and preceding experiments indicate that 3 oz. of pure copper carbonate, or 4 oz. of the weak preparations, per bushel, should be used for fall seedings. For spring seedings 2-3 oz. of pure copper carbonate, or 3-4 oz. of the weaker preparation should be used, the heavier application being made only when the seed is visibly smutted. 4. Tests were made of the effectiveness of anhydrous copper sulphate for bunt control in combination with varying amounts of Death Valley Chalk, calcium carbonate and hydrated lime. The anhydrous copper sulpha...