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Environmental Science & Technology
Tussock moth Dear Sir: I was much interested in your note on the gypsy moth and tussock moth (ES&T, Oct. 1973, p 863). I have no reason to disagree with anything said except for the very last sentence. I agree that DDT is toxic to both pests, and that it is banned from most uses at the present time. However there appears to be some question as to the effectiveness of DDT for control of tussock moth larvae under forest conditions, and no work was carried out last season to obtain this information. At least two of the biological controls tried last season were effective. One of the biological controls tested this last season was the tussock moth virus, produced by Nutriiite Products, inc., under contract to the U.S. Forest Service. This material was used on approximately 10,000 acres of forest land in Oregon that were heavily infested with tussock moth larvae. The virus was applied by aircraft at a rate of 1.0 X 10" polyhedral inclusion bodies (PIB) per acre. At this rate the virus gave 99% control; this was better control than was obtained with any of the chemical insecticides tested. The cost for the virus is comparable to the chemical insecticides tested, and it can be applied by the same methods of applications-in this case by aircraft. The virus also has the advantage of being host specific to the tussock moth larvae. l t does not harm beneficial insects, birds, fish, or mammals, including humans. Another biological control agent tested is Bacillus thuringiensis ( B . t . ) . 6 . t . is a bacteria commercially used on a wide range of crops for control of a number of lepidopterous pests, including gypsy moth. 6.t. at a rate of 7.2 billion international units ( l , U , ) per acre gave 95% control. This was better than the results obtained from any of the chemical insecticides used; the best gave 90% control. 6.t. also has the advantage of not harming beneficial insects, birds, fish, or mammals including humans. The cost of the B.t. products presently available, including Biotrol XK, a product of NPI, is very much in line with that of the chemical products tested. We feel that the biological controls are effective in controlling tussock moth larvae. We hate to see an effective tool removed from the hands of people reqonsible for pest control, especially when no replacement is available. However we feel
either of the above-mentioned products is an effective replacement for D DT. Bert Van Tassel1
Nutrilite Products, Inc. Buena Park. Calif. 90620 Air pollution companies Dear Sir: The analysis of the companies in air pollution control (ES&T, Nov. 1973, p 988) is about as complete as it could possibly be except that Carborundum is missing. This is our fault not yours-and perhaps our low-key stance has been low key for long enough. May we set the record straight. We, with our Swedish partner, are building three electrostatic precipitators in Wyoming under a $30 million contract from two power companies. In 1973 we received additional precipitator orders for more than $8.5 million, four for paper companies. We completed a successful pilot plant test for a coal burning facility, and will, again with our partner, construct a precipitator for a copper smelter. Our filter bag collector business is better than ever. Equipment of our design will be built by our Swedish partner for the Soviet Union's Kama River truck plant. This installation will be the largest ever constructed-the size of a football field and eight stories high. And we will supply the 25,200 filter bags for this system. We have been told that our design was selected because the Soviets were so impressed with our equipment at two Ford foundries in the U.S. We're not as big in air pollution as some other companies, but we're getting there. R . Marjorie Mitchell The Carborundum Co. Niagara Falls, N.Y. 14302
Sager interview Dear Sir: After a careful reading of the article (ES&T, Dec. 1973, p 1093), I believe it expresses well the spirit and function of the committee and should answer many questions for your readership. I have one minor complaint, however. I t refers to my listing as a committee member. First, my name is Lloyd L. Smith, Jr., which appears on my publications and under which name I am known in national circles, ORSANCO, as past president of the American Fisheries Society, and in international commissions. My reason for calling this to your attention
