The cost of the materials is relatively low. The basic copper arsenate and sulfur mixture costs about $2 an acre for materials for a single dusting. The sulfur alone costs about 75 cents per acre, and the cost of application is about $1 an acre for each dusting. We consider this to be reasonably cheap insurance for a crop, even in years when rust is not a menace.

In northeastern Colorado most growers of pinto beans have been dusting their fields with sulfur alone or the basic copper arsenate and sulfur mixture. In 1944, even though rust was serious, many farmers controlled it in excellent fashion. Some did not apply control measures until the disease was widespread; even then it was fairly well controlled, but two and sometimes three applications of sulfur were necessary. Some undusted fields were so severely damaged that they yielded only 6 to 10 bushels an acre, while most of the sulfur-dusted fields yielded 30 to 35 bushels an acre. By using sulfur the farmers reduced the production of overwintering spores, thus lessening the chances of a heavy rust infestation the following year. In 1945, although conditions were ideal for rust, only a single dusting in most cases was necessary for almost perfect control. The percentage of overwintering spores was so reduced that one thorough sulfur dusting early in the season killed the few rust infection centers and no secondary spread occurred. With cooperation from growers, the disease was nearly eliminated in 2 years.

In Wyoming and Montana, control measures for rust were not applied in 1944, and the disease was serious. In 1945 only a small proportion of farmers dusted with sulfur. Where this was done, the yield increases were outstanding.

In Wyoming, fields dusted twice yielded on an average of 1,600 to 1,800 pounds of seed to the acre; undusted fields averaged 800 to 1,000 pounds.

In Montana, dusting with sulfur was extremely successful. The fields dusted twice produced almost 1,000 pounds more seed to the acre than the undusted fields, and 610 pounds more than those dusted once. The best producing field, which was dusted twice, yielded 2,369 pounds an acre; the poorest undusted field gave only 380 pounds.

Several new disease-resistant snap beans have been developed by workers in the Department and State experiment stations.

Pioneer, released to growers in 1943, resists curly top and common bean mosaic. Its pods are dark green, short, round, straight, and stringless in the early stages. It is recommended only as a home-garden variety in sections where curly top usually causes severe injury to standard varieties.

Florida Belle is a green-podded snap bean that is adapted to the South, especially to Florida. It was introduced in 1943. It resists rust, powdery mildew, and common bean mosaic, and is tolerant to heat and drought. The plants are of the bush type, large and sturdy, and produce long, almost flat, light-green pods. It is used principally as a market or shipping variety.

Logan is another new green-podded snap bean, somewhat like Tender-green. It withstands powdery mildew and common bean mosaic. It is hardy and can set pods under adverse conditions, such as hot weather at blooming time. Its pods are round, long, straight, and stringless. It is well adapted to most bean-growing sections.

Several disease-resistant bush wax beans also have been released to growers since 1943. Florida White Wax is resistant to mildew, common bean mosaic, and some forms of rust. Cooper Wax, a market-garden type, resists common bean mosaic and tolerates powdery mildew. Ashley Wax, a canning type, is somewhat similar to the Refugee varieties, but has a shorter bush. It is resistant to common bean mosaic and tolerates powdery mildew.

Work on the production of varieties resistant to common and halo bacterial blights of beans is under way. Before long we can expect varieties resistant to these diseases.

THE AUTHOR

W. J. Zaumeyer, a pathologist, joined the Department in 1928 and since that time his work has dealt particularly with bacterial blights, rust, and virus diseases of beans, and root rot and leaf-spotting diseases of peas. At present his main job is to develop bean varieties that are resistant to disease and to find other ways to control certain diseases of this crop. Dr. Zaumeyer is a graduate of the University of Wisconsin.