Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. BLUE AWI-77 Issued November 1943 U. S. DEPARTMENT of AGRICULTURE ONTROLLING plant diseases pre- vents losses in crops and money and also conserves the manpower, time, and effort otherwise wasted when diseased crops fail to bring returns. Blue mold (see cover illustration) is an outstanding disease prob- lem throughout the flue-cured tobacco area. It attacks the plants in the seedbed and may weaken them and delay trans- planting, or kill the piants outright. Prevent Plant Loss In 1942 many tobacco growers lost a large part of their plants from a combination of frost and blue mold. Most serious dam- age occurred in Georgia, where 80 percent of the plants were killed, but the situation was more or less critical throughout South Carolina and North Carolina and in some parts of Virginia and Tennessee. Plant-bed tests in all flue-cured tobacco areas showed that it is practicable to protect plants effectively from both frost and blue mold damage. Sow at Proper Time Many growers still attempt to evade blue mold by the early sowing of very large bed Prepared by E. E. Clayton, Senior Pathologist Division of Tobacco Investigations Bureau of Plant Industry, Soils, and Agricultural Engineering Agricultural Research Administration U. S. Department of Agriculture REG IEE PENALTY FOR PRIVATE USE To AVOID PAYMENT OF POSTAGE, $300 re) C4 2 fe OZ G Hed g yuad y fae bo S)o 9 | au Zia za Zgr\4 peel Sipe u 230 uQe § ors 22 z G Fg 3 a TED STATES DEPARTMENT OF AGRICUL SURE AGRICULTURAL RESEARCH ADMINISTRATION Result of early sowing and failure to protect tobacco bed against blue mold or frost—about 1,800 small, weak plants to 100 square yards of bed. Photographed April 3, 1943, in Georgia, areas. The plants, however, are easily killed by frosts, and it is a far safer plan to sow the seed at the time recommended for the locality. Sow Smaller Yardage Better care can be given to a small yardage. Beds well cared for and protected against blue mold have consistently pro- duced 30,000 plants or more to 100 square yards, and even under average care beds of this size can be depended on for 15,000 plants, or enough to set almost 3 acres. —3—— AWI-77 Issued November 1943 U. S. DEPARTMENT of AGRICULTURE ONTROLLING plant diseases pre- vents losses in crops and money and also conserves the manpower, time, and effort otherwise wasted when diseased crops fail to bring returns. Blue mold (see cover illustration) is an outstanding disease prob- lem throughout the flue-cured tobacco area. It attacks the plants in the seedbed and may weaken them and delay trans- planting, or kill the plants outright. Prevent Plant Loss In 1942 many tobacco growers lost a large part of their plants from a combination of frost and blue mold. Most serious dam- age occurred in Georgia, where 80 percent of the plants were killed, but the situation was more or less critical throughout South Carolina and North Carolina and in some parts of Virginia and Tennessee. Plant-bed tests in all flue-cured tobacco areas showed that it is practicable to protect plants effectively from both frost and blue mold damage. Sow at Proper Time Many growers still attempt to evade blue mold by the early sowing of very large bed Prepared by E. E. Clayton, Senior Pathologist Division of Tobacco Investigations Bureau of Plant Industry, Soils, and Agricultural Engineering Agricultural Research Administration U. S, Department of Agriculture Treat for Blue Mold Gas and spray treatments give equally effective results if used properly. It is by no means certain, however, that all ma- terials will be available in all areas, and the control method selected may depend on the material available. Purchase Materials Now In view of the scarcity of supplies and the need for planning production well in advance, tobacco growers will do well to purchase materials required for blue mold control without delay. Result of sowing tobacco plant bed at the proper time and protecting it against blue mold and frost damage—about 30,000 large, vigorous plants to 100 square yards of bed. Photographed April 2, 1943, at the Coastal Plain Experiment Station, Tifton, Ga 8 E - ~w¢ = a GAS TREATMENT vs. SPRAY TREATMENT. There has been some question as to the comparative merits of gas and spray treat- ments for blue mold control, but a great deal of test work over a period of years shows that equally good plants and equally as many will be obtained by either method. It is merely a question of using some method properly. Gas treatment has the advantage that the grower can wait until the disease appears before beginning treatment; spray treatment is less expensive. It is well to remember that in blue mold control, mild outbreaks, which result in slight delay or loss of plants, are of no importance; hence, it is not essential absolutely to eliminate the disease. The following recommendations have been tested and are acceptable, but other methods that have been tried in various localities may be equally satisfactory. For these directions consult the county agri- cultural agent or the State agricultural college. For a fuller explanation of the treatments described in the following pages consult these publications of the United States Department of Agriculture: Farmers’ Bulletin 1799, Blue Mold (Downy Mildew) Disease of Tobacco. Leaflet 209, Gas Treatment for the Control of Blue Mold Disease of Tobacco. = Bismuth-Subsalicylate Spray Bismuth subsalicylate.....__.._.12 ounces. Vatsol O. T. C.. Water_____ 4 to 8 ounces. To make 50 gallons. Mix the bismuth and Vatsol, add a little ‘water to make a paste, and then dilute. This mixture must be agitated continuously while being sprayed. Fermate Spray Fermate. Vatsol O. T. C. V2 Ce rae eee To make 50 gallons. --..1 pound. 4 to 8 ounces. Mix as described for the bismuth-subsalicy- late spray. Fermate can be used without the Vatsol, but it will take longer to wet the powder. Other Sprays Other spray mixtures, perhaps less avail- able than the three described, also have proved effective against blue mold. For example, cottonseed oil ¥% gallon, benzyl salicylate 2 ounces, plus an emulsifier—the whole diluted to 50 gallons. All Sprays All spray treatments must begin in advance of disease appearance, preferably when blue mold is first reported in the area. Protection with either the copper oxide: cottonseed oil or the bismuth-subsalicylate = GAS TREATMENT The paradichlorobenzene treatment is the only gas treatment for blue mold control now used in this country. The material is commonly called P. D. B. oc Parabacco. Stretch regular thin cotton cover (free of holes) tightly over the bed, 10 to 15 inches above the ground. Scatter the No. 6 crystals of paradichloro- benzene over the cotton cover about sun- down at the rate of 3 pounds to 100 square yards. During warm weather use only 2 pounds. If the heavy muslin cover is thoroughly wet, 1) pounds is sufficient, but as a wet cover holds the vapors effectively it must not be left on the bed late in the morning. Few growers have found it prac- tical, however, to wet the cover. To hold the vapors in the bed, cover with a 60- to 70-thread muslin, weighing 4 to 414 ounces a square yard. This cover must be larger than the bed, so that the sides can be fastened. One cover will take care of two beds and can serve also as protection from frost damage. Start treatment about sundown and re- move the cover between 8 and 10 o’clock in the morning, before the sun gets very warm, depending on the weather. Take the cover off at 8 during warm weather or when a wet cover has been used. mixture is more prolonged than with Fer- mate, hence it is important when using Fermate not to stop spraying until the plants are set or blue mold has definitely disappeared. Fermate protection was ex- cellent as long as spraying was continued. Applications should be twice weekly and should be continued until time for trans- planting, or until the sprayed bed has had a mild attack of blue mold and recovered. Growers should plan to make 6 to 12 applications, the smaller number being adequate in mild seasons in the more northerly areas, while the larger number may be required in some years in Georgia. If the cover is well above the plants and stretched tight, the early sprays are applied through the cotton. An average of 4 gallons of spray is re- quired to 100 square yards of bed at each application. Small plants take 244 to 3 gallons, and large ones 5 to 6 gallons. All materials for both gas and spray treatments will keep at least 2 years if stored in a dry place. Treat the bed three consecutive nights if mold is present, and thereafter twice aweek. Six to eight treatments will suffice for the season. Some growers prefer to use the three - consecutive -night treatment exclu- sively and to treat only when mold is found. SPRAY TREATMENTS There are now several different spray treatments, and in careful tests conducted in 1943 all gave good blue mold control. Copper Oxide-Cottonseed Oil Spray Yellow Cuprocide.............___8 ounces. Vatsol O. T. C. 8 to 12 ounces. Cottonseed (salad) oil -.------2 quarts. Water_.................._To make 50 gallons. It is desirable to add about 8 tablespoons of molasses to each 8 ounces of Cuprocide powder. Also, a miscible oil known as S. E. C. oil can be substituted for the cottonseed oil and the Vatsol in the above. Stir the copper powder and the molasses into a thin paste with a little water. Ina separate bucket, dissolve the Vatsol in 3 quarts of water and add the 2 quarts of oil. Emulsify by pumping through the spray nozzle, and then dilute with water to 40 gallons. Wash in the copper and bring to 50-gallon volume. Keep the mixture well agitated when filling the sprayer and while spraying, so that the copper will not settle out. <= 1e—a7H27-1 FACTS ARE AMMUNITION Listen to Department of Agriculture radio net- work broadcasts for facts about wartime farming and homemaking. The National Farm and Home Hour gives farmers facts from the Department of Agriculture about the changing war needs for their products, infor- mation on Government programs to help meet their production goals, and policy discussions by our agricultural war leaders. It gives home- makers facts about food supplies, ideas on how to save food and clothing, and suggestions on keeping their families well fed under rationing. Consumer Time presents a dramatized story and discussion combined with the expert advice of a guest authority. These broadcasts present to the consumer the latest facts on conservation, nutri- tion, rationing, and the wise purchase and use of food, clothing, and household equipment, together with practical tips on wartime living. Listen to— NATIONAL FARM AND HOME HOUR Monday through Friday over stations associated with the Blue Network. 12:30 p. m. Eastern War Time. 11:30 a. m. Central War Time. 10:30 a. m. Mountain War Time. 6:15 a. m. Pacific War Time. (In California, Oregon, and Washington the early morning broadcasts are the programs presented the previous day in other parts of the country.) The National Farm and Home Hour is available to all Blue Network stations. Listen to— CONSUMER TIME Saturday over stations associated with the National Broadcasting Company. 12:15 p. m. Eastern War Time. . Central War Time. . Mountain War Time. . Pacific War Time. Consumer Time is available to all NBC sta- tions. Consult radio schedule in local newspapers for stations carrying the program, Uso: GOVEXNMENT Palatina perice — IO—O7A27T~1 11- SSANISNA WIDSIAAO ‘"O'°d ‘Se NOLONIHSVM ONIYSANION]A WHYNLIANDIYOYV ONY ‘STIOS ‘AYLSNGNI LNV1d 4O nvayna 9T I-LGELE- 00e$ ‘ADVLSOd AO LNAWAVd CIOAV OL ASN ALVAINd YOS ALIVNGd NOILVHLSININGY HOYVaSaY AveNLinoiwSy JaNITINOIAOV 4O LNAWLYVdad SALVLS Gal’ : + Ys aeliy Treat for Blue Mold Gas and spray treatments give equally effective results if used properly. It is by no means certain, however, that all ma- terials will be available in all areas, and the control method selected may depend on the material available. Purchase Materials Now In view of the scarcity of supplies and the need for planning production well in advance, tobacco growers will do well to purchase materials required for blue mold control without delay. “sowing tobacco plant bed at the proper time and .it against blue mold and frost damage—about e, vigorous plants to 100 square yards of bed. Dhed April 2, 1943, at the Coastal Plain Experiment y Ga. =i 16—37327-1