Control A:l 



CHEKIGAL CONTROL OF NEMATODES 



Historical 



Almost as soon as it was realized that nematodes in the soil were 

 capable of damaging crop plants, attempts were made to kill them by 

 means of chemicals. The literature contains a long list of substances 

 which have been tested for this purpose. As early as I88I, Ktoin 

 attempted to kill nematodes with carbon bisulphide, though without 

 conspicuous success. Carbon bisulphide was also recommended by Bessey 

 (1911) for killing nematodes, his methods being copied from those used 

 for control of Phylloxera , an insect pest of grapes, in France. The 

 method was essentially that used today; application of measured amounts 

 in holes punched at intervals in the soil. Shortly after the first 

 VJorld War, chloropicrin was tested for nematode control in England witb 

 good results. About ten years later, Johnson and Godfrey again tested 

 chloropicrin and developed methods and machinery for field application 

 in pineapple fields in Hawaii. By 1937, this work was sufficiently 

 advanced so that Innis, Speiden & Co. started commercial development 

 of chloropicrin, finding most of their customers among greenhouse 

 owners. About I9U0, methyl bromide was found to be a good nematocide 

 and shortly thereafter, Dow Chemical Company entered the nematocide 

 business, again finding most of their customers among greenhouse 

 owners . 



During the World War II years, the value of a mixture of dichloropro- 

 pane (D-D) was tested by Carter in Hawaii and ethylene dibrornide (EDB) 

 was tested by the Dow Chemical Company, with good success in both 

 cases. These being much less expensive than chloropicrin and methyl 

 bromide, they could be used on a large scale. Intensive efforts to 

 develop a market for them started in 19h^. In 1950, Shell Chemical 

 Corporation started development of Chlorobromopropene (CBP). This 

 company soon folloiired this irith the development of another chemical 

 first referred to as OSI897, novi trademarked Nemagon, and chemically 

 designated as l,2-dibromo-3-chloropropane. 



The Virginia-Carolina Chemical Corporation, at about this same time, 

 released a commercially available chemical called V-C13 Nemacide, the 

 active ingredient of which is 0-2-l4.-dichlorophenyl O-O-diethyl phos- 

 phorothioate. This was sold as a water emulsifiable form to be applied 

 to the soil as a pre- or post-planting treatment and was one of the 

 first of the new nematocides to be recommended for treatment of soi] 

 around living plants. 



About 195?, an experimental soil fumigant, formerly called compound 

 N-869, was released for comjnercial use as Vapam, a liquid manufactured 

 by the Sta\iffer Chemical Company. Its active ingredient, sodium methyl 

 dithiocarbamate, is lethal not only to nematodes but to various soil 

 fungi and insects and x^'eeds. Thus, it is considered as a temporary 

 soil sterilant. 



