CAUTION: Rubber gloves absorb methyl bromide which may result in skin injury if they are worn continuously. (g) Naphthalene. Flake naphthalene, free from tar, is required. cars for aeration. If it is absorbed by the system, prompt action may prevent serious consequences. The established principles of first aid in HCN poisoning are: (1) Induce continued heavy breathing of fresh air by artificial respiration, Naphthalene is not explosive and it using the Shaefer (prone pressure) burns only with difficulty. It is advismethod; (2) neutralize the gas poison-able, however, to keep the material in ing with weak ammonia fumes or aro- the solid and gaseous form away from matic spirits of ammonia; (3) call a fire. physician. Small bottles of ammonium carbonate, as the source of ammonia fumes, should be readily available as an inhalant at all times. (e) Lead arsenate. Lead arsenate which satisfies the standard requirements of the chemical for use as an agricultural spray is required. It should contain at least 30 percent arsenic pentoxide, and not more than 0.75 percent water-soluble metallic arsenic. It should be obtained in powdered form to which no stickers have been added. Lead arsenate should be stored in a dry place that is not accessible to animals. Lead arsenate is poisonous to man and animals. When applying the material, the worker should wear gloves to protect his hands, since the poison may be absorbed into the system through cuts and abrasions of the skin. The worker should keep his hands away from his mouth at all times while handling the material and be sure to wash thoroughly before eating. If absorbed by the system, call a physician, give an emetic such as warm water and mustard, and give milk or white of egg. (f) Methyl bromide. The commercial grade is required. Containers of methyl bromide should be stored in a cool, well-ventilated place. Avoid leakage by seeing that the valves on the cylinders are tightly closed. Long exposure to naphthalene may cause giddiness and headache. When these symptoms develop, the individual should get into the open air. (h) Paradichlorobenzene. A technical or C. P. grade of small to medium size crystals is required. Paradichlorobenzene burns only with difficulty. It is advisable, however, to keep the material from fire. Long exposure to the gas may cause giddiness and headache. When these symptoms develop, the individual should get into the open air. TREATMENT OF SOIL IN ABSENCE OF PLANTS (i) Potting soil. Potting soil must be treated by the use of heat, carbon disulphide, naphthalene, or lead arsenate. Fumigated or heat-treated soils should be aerated to remove excessive fumigant or heat before using for potting plants. when stored, the soil must be kept and handled in such a manner as to prevent reinfestation. When stored for a long time, without aeration, it is advisable to thoroughly mix the upper and lower layers in the bin. When used as recommended, these treatments do not impair the fertility of the soil. Lead arsenate treatments are more limited in their application because of the susceptibility of some nursery plants to arsenical poisoning. E-418 of the Bureau of Entomology and Plant Quarantine gives some information on the susceptibility of nursery plants to lead arsenate in the soil. Methyl bromide is a gas at ordinary temperatures. As it has only a very slight odor, toxic concentrations of methyl bromide may be encountered and the persons so exposed may be unaware of the danger. While methyl bromide is not so toxic as hydrocyanic and type of soil. Soil of any type may be (1) Heat treatment-(i) Condition treated, provided it is friable. (ii) Temperature. The soil must be heated throughout to 130° F. acid, it is dangerous to inhale the gas or to get the liquid in contact with the skin. Rubber gloves should be worn while releasing the liquid methyl bro- (iii) Period of treatment. The temmide either from cylinders or applica-perature of the soil must be maintained tors. at 130° F. for 30 minutes. (2) Carbon disulphide fumigation—(i) Equipment. A gas-tight bin or box is required. It is necessary to have the top, sides, and bottom tight. (v) Application. The fumigant must be thoroughly mixed with the soil, and the soil then placed in a pile. (vi) Period of fumigation. The soil must be left undisturbed for 1 week. (4) Lead arsenate treatment—(i) Season. The treatment must be applied be (ii) Condition and type of soil. Soil of any type may be fumigated, provided it is friable and thrown loosely into the bin or box. Wet soil must never before August 1. fumigated. (ii) Condition and type of soil. The (iii) Temperature. The temperature soil must be friable. Wet soil must never must be at least 45° F. when the fumigant be treated. The treatment is recomis applied and must not fall below 40° F. mended only for soils which are slightly during the course of the treatment. acid or neutral in reaction. Any type of (iv) Dosage. One pound (352 cubic soil may be treated provided it meets centimeters) to 1 cubic yard. these requirements. (iii) Dosage. Two pounds to 1 cubic yard. (iv) Application. The lead arsenate must be thoroughly mixed with the soil. (v) Application. One method is to apply the fumigant while the soil is being put into the bin or box. Place 18 inches of soil in the bin or box. Inject carbon disulphide at the rate of 176 cubic centimeters for each square yard of surface, distributing the material uniformly in holes 2 inches deep and 18 inches apart, using 44 cubic centimeters to each hole. Fill the holes with soil im-lowing October 1 and June 15. mediately after the liquid is injected. When the first 18 inches of soil have been treated, put in 18 inches more and repeat the operation. This can be repeated until the container is filled. from soil and potted in soil treated in (v) Period of treatment. Plants freed the above manner by August 1, may be certified for shipment between the fol Another method is to apply the fumigant after the box or bin has been filled. This is done by making holes from the surface to the different levels, so that the carbon disulphide is applied in the same positions as by the first method. The liquid, in this case, must be poured into the deep holes through a tube, or injected to insure that it reaches the proper level. (vi) Period of fumigation. The box or bin must be sealed and left undisturbed for 48 hours. (3) Naphthalene fumigation—(i) Equipment. No special equipment is necessary. It is not necessary to cover the soil. (vi) Handling of potted plants. When plants potted in lead-arsenate-treated soil are plunged in beds or set in frames exposed to possible infestation, the soil of these beds or frames must previously the rate of 1,500 pounds per acre. have been treated with lead arsenate at (vii) Treated plants carried after June 15. When plants potted in soil treated as prescribed are carried after June 15, they may be again eligible for certifica tion between October 1 and June 15 of the second year if, on August 1 of the second year, analyses show the soil to contain lead arsenate at the rate of 2 pounds per cubic yard. (j) Shipments of sand, soil, earth, peat, compost, and manure. Shipments of sand, soil, earth, peat, compost, and manure must be treated by the use of heat or carbon disulphide. The instructions given in (i) (1) and (i) (2) must be followed. (ii) Condition and type of soil. Soil of any type may be fumigated, provided it is be used between June 15 and October 15, (1) Type of car. Tight box cars must friable. Wet soil must never be fumi-inclusive, and may be used at other gated. (iii) Temperature. times of the year. Open freight cars, The temperature of the steel gondola type, may be used between October 16 and June 14. In must be at least 50° F. (iv) Dosage. Five pounds to 1 cubic cars of this type, with dump bottoms, yard. planks must be laid on the bottoms and covered with heavy paper, in a manner | square and 30 inches long, to be placed approved by the inspector. at the boundaries of the certified plots and marked by the Department. (2) Doors. The doorways of box cars must be boarded up and covered with heavy paper up to a point beyond the height of the sand, soil, etc. Certified cars must have the doors closed and fastened while en route within the regulated area. (3) Depth of sand, soil, etc. In box cars, the sand, soil, etc. must not be loaded to such a depth as would restrict the overhead working space and hamper the work of the men applying the treatment. In the open type cars, the material should not be piled above the sides of the car. (4) Covering with canvas, etc. When open type cars are used, canvases or heavy paper must be used to cover the surface as the treatment is applied. These covers must be free from holes and a foot or more wider than the width of the car. Where several pieces are used, they must be large enough to allow for overlapping at least 1 foot. The covers must be fastened down at the sides of the car and weighted on the surface, particularly where they overlap. (k) Soil in and around coldframes, plunging beds, and heeling-in areas. Soil in and surrounding coldframes, plunging beds, heeling-in areas, etc., must be treated with lead arsenate, except, under special conditions, when the inspector may authorize the use of heat, carbon disulphide, carbon disulphide emulsion, or naphthalene. With the exception of lead arsenate, the treatment must not be applied when adult beetles are present. An exception may be made in the case of beds protected from beetles. Safety zone: In addition to the area desired to be certified, a strip 3 feet wide must be treated around the entire coldframe, plunging bed, or heeling-in ground. No plants will be certified from this strip. In the case of coldframes, etc., extending into the ground to a depth of 12 inches or more, no safety zone is required. Marking: In the case of coldframes, etc., having fixed boundaries, proper designations will be made on them by the Department representatives. In all other cases, the nurseryman shall furnish suitable stakes, at least 4 inches (1) Lead arsenate treatment-(i) Season. The treatment must be applied before August 1 if the land is to be used in the fall. (ii) Condition of soil. The soil must be friable and in good tilth. (iii) Dosage. Thirty-five pounds to each 1,000 square feet, or 1,500 pounds per acre. For subsequent re-treatments, the quantity required to restore the original concentration, as determined by chemical analyses, must be applied. (iv) Application. The lead arsenate must be thoroughly mixed and incorporated with the upper 3 inches of soil. (v) Period of treatment. Plants must not be placed on or in the soil thus treated until after October 1. (2) Heat treatment. Hotbeds, equipped with steam pipes or electrical resistance coils in the soil, may be treated by heating the soil to at least 130° F. and maintaining this temperature for 30 minutes. (3) Carbon disulphide fumigation—(i) Equipment. A heavy paper, or other gas-proof cover, must be provided to cover the soil during the fumigation period. (ii) Condition of soil. The soil must be friable and in good tilth. A wet soil must never be treated. (iii) Temperature. The temperature of the soil at a depth of 6 inches must be at least 45° F. when the fumigant is applied, and must not fall below 40° during the period of treatment. (iv) Weather conditions. The ideal conditions are a warm, humid atmosphere without wind. (v) Dosage. Six pounds (2,100 cubic centimeters) to 100 square feet of surface. (vi) Application. Carbon disulphide must be uniformly distributed over the surface of the bed, plot, or heeling-in area. Apply it in holes 12 inches apart and 1 to 2 inches deep, putting 21 cubic Fill each centimeters into each hole. hole with soil immediately after the liquid is poured. Cover each section as soon as the fumigant is applied. (vii) Period of treatment. The soil must remain covered for 48 hours. (4) Carbon disulphide emulsion treat- should be understood that these treatment-(i) Equipment. Suitable tanks, ments have not been tried on all variebarrels, or tubs for preparing the emulsion and 24-gage galvanized-iron collars 10 inches wide and not more than 4 feet square, for applying the treatment, must be provided. (ii) Condition of soil. The soil must be friable. The surface must be level and not disturbed by recent cultivation. Drainage conditions must be such that the solution does not disappear from the surface in less than 10 minutes or more than 5 hours. (iii) Temperature. The temperature of the soil at a depth of 6 inches must be at least 45° F. when the treatment is applied, and must not fall below 40° during the period of the treatment. (iv) Dosage. Two and one-half gal lons of dilute emulsion to each square foot. The concentration is dependent upon the temperature. Follow table 3 of paragraph (m) (2). (v) Application. Level the surface of the soil, removing weeds and debris. Force a galvanized-iron collar 3 inches into the ground, and firm the soil against the metal. Place another collar next to the first, and so on. When enough collars are in place, pour the dilute emulsion into the basins formed within the collars. As soon as the liquid has disappeared from the surface, the collar may be lifted and set in another position. (vi) Period of treatment. The soil must not be disturbed for 48 hours. (5) Naphthalene fumigation—(i) Condition of soil. The soil must be friable and in good tilth. (ii) Temperature. The temperature of the soil at a depth of 6 inches must not be less than 50° F. during the period of the treatment. (iii) Dosage. Forty-six pounds to 1,000 square feet, or 2,000 pounds per acre. (iv) Application. The naphthalene must be thoroughly mixed and incorporated with the upper 3 inches of soil. (v) Period of treatment. The soil must not be disturbed for 1 week. TREATMENT OF SOIL ABOUT THE ROOTS OF PLANTS The effect of insecticidal treatments on plants, when applied to soil about their roots, varies with the variety, age, vigor, and condition of the plants. It ties of plants, or under all of the varied conditions in the nurseries. In general, it is not possible to destroy an insect in close proximity to the roots without causing some damage to the plant. While guarantees can not be given that no injury will be caused to the plants, the treatments are recommended only for those plants which experience has shown were not seriously injured. It must be understood by the nurseryman that no liability shall attach either to the United States Department of Agriculture or to any of its employees in event of injury. After all treatments, the plants must be handled in such a manner as to prevent reinfestation. (1) Treatment of plants after digging-(1) Removal of infestation. With some deciduous and herbaceous plants, infestation can be removed by shaking and washing all soil from the roots. Only such root masses as can be thoroughly examined and absence of infestation verified may be certified by this procedure. ment. A water tank, equipped with a (2) Hot-water treatment-(i) Equipsuitable heating device and circulating system, must be provided. (ii) Temperature. The water must be maintained at 112° F., with a variation of not more than ±0.5°. Before the plants are immersed, thermometers must be inserted in the center of at least three of the largest clumps, baskets, or root masses placed at each end and at the center of the tank. In addition, three thermometers must be placed in the water of the tank in the same relative positions as those in the root masses. Temperature readings from each of these thermometers must be recorded on Form No. 91. (iii) Application. The root masses must be immersed completely. (iv) Period of treatment. Seventy minutes after the root masses are heated to 112° F. (v) Varieties of plants. The varieties which have been treated successfully by this procedure are given in Technical Bulletin 274. (vi) Preparation of plants. Large clumps should be divided as much as pos (1) Season. The treatment must be applied between October 1 and May 1. sible without injuring the roots. Excess (4) Paradichlorobenzene fumigation— soil should be removed and the roots pruned. Small plants and root stocks may be packed loosely in wire baskets or in other suitable containers, Provided, The water can circulate through the masses. Large plants must be placed individually in the water. (ii) Varieties of plants. The following varieties of plants have been treated successfully by this procedure: Aquilegia sp. var. Mrs. Scott Elliott's hybrid, Anemone hupehensis, Artemisia dracunculus, Azalea amoena, A. kaempferi vars. Cleopatra, Fedora, Othello, and Salmon Beauty, A. hinodegiri, A. obtusa kiusiana var. Coral Bells, Aster alpinus, Campanula medium, Ceratostigma plumbaginoides, Chrysanthemum sp., Dianthus caryophyllus var. Abbotsford Pink, Digitalis purpurea, Eupatorium coelestinum, Helianthemum glaucum croceum, Iberis amara, Myosotis sp., Pachysandra terminalis, Phlox sp. var. R. P. Struthers, Santalina chamaecyparissus incana, Sedum acre, Sempervivum alberti, Stokesia laevis, Thymus serpyllum, Viola sp. vars. Jersey Gem and Rosina. (iii) Preparation of plants. Excess soil should be removed and the mass reduced as much as possible without injuring the roots. The plant ball should be (iv) Application. The root masses moist, but not wet. Pots must be removed must be immersed completely. Large from potted plants. When burlap on balled plants is of coarse weave, it may be left on the balls, but when it is closely woven, it must be removed. (iv) Preparation of plunging soil. The paradichlorobenzene must be thoroughly mixed with a light sandy loam, or sand, which is moist but not wet, and free from lumps, stones, and debris. It must be mixed immediately before using. (v) Care of plants during treatment. If it is necessary to water the plants during the treatment to prevent desiccation, the operation must be limited to a light syringing, under the supervision of an inspector. (vii) Preparation of plants. clumps should be divided as much as possible without injuring the roots. Excess soil should be removed. No wet root masses or root masses measuring more than 6 inches across the narrowest dimension must be treated. The temperature of the root masses must be at least 60° F. before treatment. Small plants and root stocks may be packed loosely in (vi) Care of plants after treatment. It wire baskets or other suitable contain-is advisable to avoid excessive watering ers, provided the dipping solution can of the plants after treatment in order circulate through the masses. Larger to permit any residual gas to escape from root masses must be placed individually the plant balls. in the dip. (viii) Care of plants after treatment. Tubers should be dry when packed. Avoid subjecting treated plants to freezing temperatures shortly after treatment. It is advisable to allow plants which are to be potted to stand in the open to permit evaporation of the fumigant before placing them in soil. (vii) Complete coverage. Temperature: The temperature of both the treating soil and the soil ball must not be less than 50° F. during the period of treatment. To prevent injury to the plants, it should not go above 65°. Dosage: Ten pounds per cubic yard of mixing soil (6 oz. per cu. ft.) for soil balls up to 6" in diameter at the nar |