CONTROL OF INSECTS IN TOBACCO 31 



the very young larvae are usually near the surface also, and little 

 penetration of gas is required to kill adults, eggs, pupae, and many 

 larvae. With careful timing the largest possible proportion of moth's 

 and beetles can be killed. 



Suction light traps should be installed and placed in operation 

 before the earliest spring emergence. This date ranges from March 1 

 in eastern South Carolina to April 15 at Eichmond, Va., and probably 

 May 1 in eastern Pennsylvania. 



Applications of a pyrethrum-oil spray containing 0.2 percent of 

 pyrethrins in a cigarette-tobacco warehouse should start when suction 

 light traps show 10 tobacco moths a week. If or when traps show a 

 catch of 10 cigarette beetles a week, a spray containing 1 percent of py- 

 rethrins should be used. Should the spray fail to control the cigarette 

 beetle, the warehouse should be fumigated as soon as possible after 

 the peak of emergence. Under such conditions the minimum infesta- 

 tion that would probably justify fumigation of cigarette tobacco 

 would be indicated by a weekly catch of 200 to 300 beetles. In ware- 

 houses of cigar tobacco fumigation might be justified by a much lighter 

 infestation. If necessary, the fumigation should be repeated. 



If a sprajf is not used, two to four fumigations a year are needed, 

 depending on the degree of infestation. At Richmond, Va., the most 

 desirable times for such fumigations have usually been May 15 to 31, 

 June 25 to July 5, August 10 to 25, and September 15 to 30. 



In all fumigation of tobacco, the gas should be applied only by 

 a person especially trained for the work. For warehouse or fac- 

 tory fumigation it is best to employ a licensed pest-control operator. 

 An employee especially trained should be solely responsible for at- 

 mospheric or vacuum-chamber fumigation. 



COST OF INSECT CONTROL 



The cost of insect control varies from year to year with the price 

 of labor, insecticides, and other things. Cost figures are available for 

 cigarette tobaccos only. For 1948 the cost of treating tobacco ware- 

 houses with pyrethrum-oil spray to control the tobacco moth ranged 

 from 8 to 13 cents a hogshead. It cost about 18 cents a hogshead to 

 spray for control of the cigarette beetle. The cost of warehouse fumi- 

 gation ranged from IT to 32 cents a hogshead and averaged about 

 26 cents for each fumigation. In 1949 the costs of both spraying and 

 fumigation were substantially higher. 



Vacuum fumigation may range from $1.00 to $3.00 a hogshead. 

 The charge for custom fumigation in vacuum at Newport News, Va., 

 in 1950 was about $1.25 a hogshead of flue-cured tobacco. This in- 

 cluded the cost of the fumigant, labor, electric power, and amorti- 

 zation of equipment. 



SAFEGUARDS IN FUMIGATION 



Carelessness is responsible for most of the accidents in industrial 

 fumigation. The following precautions should always be taken : 



Employ only trained men, preferably licensed pest-control 

 operators, in the fumigation of warehouses and factories. Oper- 

 ators must abstain from intoxicants while working. 



