NAPHTHALENE AS A GREENHOUSE FUMIGANT 3 



HISTORY OF NAPHTHALENE AS AN INSECTICIDE AND INSECT 



REPELLENT 



On Field Crops 



Twenty or more years ago, naphthalene was more generally used for pre- 

 venting insect damage on trees, vines, and vegetables in Europe than in 

 America. According to Bourcart (4) at least a dozen mixtures included 

 naphthalene in their formulas and their uses were widespread. In the sprays, 

 washes, and dips, the naphthalene was generally combined with coal tar and 

 lime, while some form of sulfur or copper was occasionally added. Some of the 

 materials of this nature which were frequently used were known as Crouzel's 

 Anticryptogamic, Balbiani's Ointment, Occidine, and Rathay Bouillie. Solu- 

 tions of naphthalene, 1 part in 8 parts of alcohol or benzene (1 pound in a 

 gallon), were also used. Dusts for the treatment of growing plants were pre- 

 pared by mixing naphthalene with sulfur, pyrethrum, lime, or ashes. For 

 killing and repelling soil insects such as wireworms, naphthalene was mixed 

 with sand or with sawdust and sown with the seed or worked into the soil 

 with the manure. More recent literature indicates that naphthalene is less 

 popular, probably because it has been supplanted by more effective materials. 



In the United States, one of the oldest remedies for preventing injury to 

 stored clothing, wool, fur, and leather by clothes moths or carpet beetles is 

 storing them with naphthalene. Back (1, 2) recommends 1 pound in each 10 

 cubic feet for this purpose. To control fleas in a building, Bishopp (3) recom- 

 mends using 5 pounds in each ordinary sized room. 



More recently, a wash prepared with soap, naphthalene, flour, and water 

 for painting the trunks of trees to prevent oviposition by the flat-headed 

 apple tree borer has been recommended in Michigan (11). A somewhat similar 

 emulsion of naphthalene and cottonseed oil was used by Snapp (15) in Georgia 

 for peach borer control with somewhat unsatisfactory results. 



The carrot rust fly was effectively controlled by Glasgow (5) by broadcasting 

 6 applications of crude naphthalene at the rate of 400 pounds per acre, and 

 Maughan (9) in New York used it quite successfully to control onion thrips in 

 the field. The experiments of Weigel et al. (20) have shown that naphthalene 

 when stored with gladiolus corms provides a very effective and practical control 

 of the gladiolus thrips. 



The larvae, pupae, and eggs of the Japanese beetle are killed by thoroughly 

 mixing the soil with naphthalene flakes (19). When used at the rate of 5 

 pounds for each cubic yard for potting soil, and 1,000 pounds per acre or 23 

 pounds per 1,000 square feet in cold frames, hotbeds, or nursery rows, naphtha- 

 lene constitutes an approved treatment for disinfecting the soil of this pest. 



It appears that the use of this material for insecticidal purposes is now 

 increasing in this country. 



On Greenhouse Crops 



Among the first records of the use of naphthalene as a greenhouse fumigant 

 are those discussed in the reports of the Experimental and Research Station, 

 Cheshunt, Herts, England. Here, Speyer (16"i in 1923, after preliminary 

 laboratory work with a large number of volatile liquids and volatile solids 

 dissolved in liquids, found sufficient encouragement in white flake naphthalene to 

 use it on a practical scale. At first, the naphthalene was dissolved in tetra- 

 chlorethane, this solution being poured on the ground and on the steam pipes 



