208 



treatment, ami no experiments liave been made from which any guaranty of suc- 

 cess following it could be given. It might, however, be worth a trial, and I should 

 be glad to have you report the results of any experiments you might make in this 

 direction. The tent, to prevent the esea])e of the fumes of this substance, which is 

 very volatile, should be thoroughly oiled or painted and the connection with the 

 ground should be made as tight as possible by means of earth or boards. It seems 

 that the difficulty arises from allowing the shocks to remain so long in the tield 

 after harvesting, but I am not at all sure that the infestation does not sometimes 

 take i)lace, that is, that the eggs are deposited in the heads before the wheat is 

 cut. This is more apt to be the case if the wheat is allowed to become very ripe 

 before harvesting. Would it not be advisable to adopt the plan of the Western 

 farmer before the advent of the self-binder and head the wheat, threshing imme- 

 diately, so that it can be stored in bins, where it will be comparatively exempt from 

 the attacks of the moth and where treatment wuth remedies is more easy and satis- 

 factory ? 



If, however, as appears from your letter, you have just threshed your wheat, it 

 ought to be possible to destroy the insects and prevent further injury. This can be 

 done if the grain is stored in comparatively tight bins. The treatment consists in 

 the use of bisulphide of carbon, which should l)e added near the top of the pile of 

 grain at the rate of one and a half pounds of l)isulphide to each ten bushels of grain. 

 A ball of tow attached to a stick may receive the charge of bisulphide, like a sponge, 

 and be plunged into tlie top of the grain. When necessary the stick may be with- 

 drawn and a fresh charge inserted. The action of the bisulphide in a comparatively 

 tight bin lasts ordinarily about six weeks, after which a fresh charge is required. 

 The substance does not injure the wheat in the least, provided it is not used too 

 freely nor for too long a period. — [September 17, 1891]. 



Treatment of the Boll Worm. 



I wrote you some mouths ago in regard to best methods of combating ravages of 

 the Boll W^orm and you were kind enough to reply. Now I seek additional informa- 

 tion, as I see abundant evidences that we will lose our cotton again by them. 



(1) What poison is best, Paris green or London purple? 



(i) For small farmers, what method of application is most efficient f 



(3) If by spraying, what apparatus is most satisfactory; the same, if dusting the 

 poison on is advised? 



(4) If spraying is advised, what is the proper strength of poisoned water? How 

 much poison to gallon f 



(.5) What is the chemical name of Paris green and Loudon purple, and if either 

 can be made soluble in water and still retain its poisonous properties? » * - 

 — [H. L. Tate, Smith County, Tex. 



Keply.— The fourth report of the United States Entomological Commission con- 

 tains in its first part, treating of the Cotton Worm, an elaborate chapter on the 

 application of arsenical poisons to the cotton plant, and upon referring to that por- 

 tion of the report (pp. 136-153) you will find full particulars regarding the points 

 you ask me in your last letter. We have pointed out that a timely application of 

 Paris green or London purple not only protects the plants from the Cotton Worm, 

 but is at the same tinu- the best remedy that can be recommended for the destruc- 

 tion of the you tig Boll Worms before these enter the bolls. The report was pub- 

 lished in 1885, and since that time no new discoveries have been made regarding the 

 mode of application of these poisons. 



(1) London i>urple can not be said to be better than Paris green, but is a good 

 substitute and nnuh less expensive (see 4th Report, pp. 143 and 151). 



(2) This depends entirely upon circumstances. Water is often not handy, and 

 email planters are liable not to have any spraying apparatus on hand. For these 



