400 REPORr UNITED STATES ENTOMOLOGICAL COMMISSION. 



The spraying of coal-oil variously diluted 5 the use of ^' Buhach" or Per- 

 sian insect-powder (fresh powder, from plants raised in California, was 

 sent us by G. N. Milco, of Stockton, Cal.); Yeith's insect-fluid^ (also 

 sent by the manufacturers) ; sulpho-carbonates ; bisulphide of carbon; 

 hot alum water; naphthaline; quassia water in varying strength; strong 

 tobacco water; uric. or hippuric acid; sulphuric acid diluted with fifty 

 times its weight of water; ^ few teaspoonfuls of saltpeter in a bucketful 

 of water; saltwater; vinegar ; copperas water; cresylic soap. 



Owing to unfavorable weather while in Colorado, Professor Packard 

 failed to carry out experiments as completely as was desired ; but we 

 quote the following portions of his report, and shall refer in other chap- 

 ters to other observations he made for the Commission : 



The instrument in general use for destroying locusts is the coal-oil or coal-tar "pan," 

 as it is called, many modifications of which are made to suit individual preferences or 

 special emergencies. 



As to chemical experiments, those chemicals only could be tried which would affect 

 the insects by direct application to them, since, as remarked in a former letter, 

 at the time of my visit the locusts were all young, very sluggish, and were not feed- 

 ing. Consequently, of the hundred or more insecticides which have been patented in 

 this country, most of which are to be used in protecting fruit-trees and other plants 

 from the ravages of feeding insects, few could be tried. Of those remaining, aside 

 from this class, the experiments of Dumas, conducted in France with a view to discover 

 some agent destructive to the Phylloxera, have shown that the majority of such agents 

 as are fatal to that insect are also destructive to the vines or detrimental to the soil, 

 and, consequently, indirectly injurious to the vines. It would be useless here to enu- 

 merate the large number of natural and chemical compounds which the distinguished 

 French chemist experimented with. Their number exceeds a hundred, and includes a 

 large majority of those substances generally recognized as poisons. The report is to 

 be found in "Annales de Chiraie et de Physique," o*' s^rie, tome vii, 1876. The general 

 conclusion reached is that for attacking the Phylloxera the sulpho-carbonates and coal- 

 tar are the best means to be employed. In dealing with locusts, however, the problem 

 is an entirely different one from that to be solved in regard to the Phylloxera. In one 

 case we have an active insect, continually moving from place to place above ground, 

 while in the other a comparatively stationary insect, living under ground and remain- 

 ing 80 as long as its food lasts, is to be dealt with. In the latter case rhe point was to 

 find poisons which, giving off vapors during a sufficient length of time and acting in 

 a confined space, would destroy the subterranean pest. In the former, however, the 

 object has been to find some chemical which, acting by immediate contact with the 

 actively moving locust, would cause its death, or which, scattered on the plants which 

 it affects, would enter its system and so act as a poison. As before remarked, only the 

 former of these objects could be kept in view, owing to the activity of the insects. 

 No experiments, therefore, having in view the protection of plants could be made. 



The following trials were made : 



Buhach, or Persian insect-j^owder. — Several locusts immersed in this for from three- 

 quarters of an hour to an hour, after being liberated from the bottle (they were com- 

 pletely immersed in the powder), brushed off the powder and moved off, although 

 feebly. When the powder is blown upon them, as prescribed, they quickly brush it 

 off, and disappear unharmed. 



VeiWs insect-fluid. — This proved to be very effective, killing locusts and plants with 

 great celerity. Analysis shows it to be made up of oil of turpentine and a tincture 

 (probably) of camomile. The oil of turpentine may well account for its deadly effects. 



. sd '. — 



•'^ This is manufactured in Philadelphia, and recommended fcr all sorts of insects, for many of which 

 it could be of no possible use; and, like many other patent rostrums for all insect ills, it is very much 

 of an imposition. 



