RELATIVE EFFECT OF PYRETHRUM ON DIFFERENT INSECTS. 179 



is preferable on that score alone ; and in tlie future it can hardly fail also to be the 

 cheaper of the two. This is the more likely, as the tea made of the leaves and stems 

 has similar, although considerably weaker, effects; and if the farmer or fruit-grower 

 were to grow the plants, he would save all the expense of harvesting and grindiug 

 the flower-heads by simply using the header, curing the upper stems, leaves, and 

 flower-heads all together, as he would' hops, making the tea of this material by the 

 hogshead, and distributing it from a cart through a syringe. It should be diligently 

 kept in mind that the least amount of toiling will seriously iujure the strength of 

 this tea, which should be made with briskly boiling water, but then simply covered 

 over closely, so as to allow of as little evaporation as x)ossible. The details of its 

 most economical and effectual use on the large scale remains, of course, to be worked 

 out by practice. 



Having no sufficient supply of flower-lieads at our disposal we bave 

 been unable so far to repeat these experiments. Mr. Hubbard made 

 an infusion by pouring hot, not boiling water upon the powder, but 

 found it ineffective and quite worthless, and we have had similar re- 

 sults with the decoction of the powder. 



The wet application of Pyre thrum, in whatever form it may finally 

 prove most convenient, is unquestionably superior to its application 

 in powder form, the former being by far more economical and, with the 

 improved appliances, enabling us the better to reach all the worms. 



Effect of pykethruivi upon other insects. — While arsenical 

 poisons directly ^^ affect only those insects which feed on the leaves of 

 the cotton plant, or, in other words, only the enemies of the plant, Py- 

 rethrum affects all insects that hai^pen to be on the plants at the time 

 of the application. Since among these are great numbers of some of 

 the most efficient enemies of the worm, it is not without interest to 

 record here such observations as have been made incidentally in regard 

 to the effect of Pyrethrum on other insects besides Aletia, even if they 

 include some that have no connection with the cotton plant. Mr. Hub- 

 bard reports as follows : 



Tried upon different insects, pyrethrum appears to affect the higher Hymenojatera 

 more than other insects. Ants are almost instantly affected. Wasps continue feed- 

 ing for about 20 seconds, and are violently affected in from 1 to 2 minutes. Larvae of 

 all kinds are more quickly affected than images. Termites, owing probably to their 

 tender bodies, are instantly affected and soon killed. Spiders resist longer than any- 

 thing else. They sometimes change their skins when dusted with the powder. Copris 

 and Phanceus are slightly affected and long resist the action of the powder. Scolo- 

 pendridce affected similarly to spiders. Bugs slightly affected, especially the large 

 and heavily armed predaceous species. Roaches very violently affected. These ob- 

 servations refer to the immediate action of the dry and undiluted powder, and are 

 comparative only. 



Mr. Schwarz records the following observations on this point : 



A thorough application of my alcoholic extract (10 drams to 2 gallons of water), 

 and of my pyrethrum-water (200 grains of powder to 2 gallons of water), affected other 

 insects as follows : They had no visible effect on all spiders, without exception, on 

 the larvaB of Lagoa sp., Hyperchiria io, Acronyeta obl'mita, and Ecpantlieria scribonia ; 

 they affected, but not fatally, the common Black Cricket, the various species of grass- 

 hoppers and their larvte, the ground-beetles so common under the fallen leaves at 

 the base of the plants {Aniaodaciylus rwaticus, Flatynvs ;punctiformi8 and P. macuUcollis), 



