EXPERIMENT STATION WOKK WITH INSECTICIDES. 269 



Ion of water, after whicli the mixture is broii<;lit to a hoilinj; point, 

 thus forniin«: a thin paste, which shouhl be stirred so as to prevent the 

 formation of lumps. In practice the paste may most conveniently be 

 prepared in '20 or 25 gallon lots. Fifteen pounds j)owdered concen- 

 trated lye and 18 pounds of sulphur are then to be Iwiled t()<rether in 

 20 pillons of water. After the sulphid of potash stock solution and 

 the flour paste have been prepared, 10 to 1.") pounds of sublimed sul- 

 phur anil 14 to 20 pounds <rround sulphur should be placed in the 

 spray tank with 4 gallons of the flour paste and from 1 to 2 gallons 

 of the sulphid of potash stock solution. Water is then added to make 

 100 <rallons. It is reconnnended that everv etl'ort be nmde to wet both 

 the lower and upper surfaces of the leaves and to wet the twigs. For 

 an almond tree 20 feet in diameter from 12 to 14 gallons of spray are 

 required. 



THE HESSIAN FLY. 



The Hessian fly has long been one of the important enemies of wheat, 

 and has been studied at several of the experiment stations. In Ken- 

 tucky " it is reconnnended that in order to escape serious fall injury 

 from the Hessian fly, wheat should be planted before October 6 in 

 ordinary years, or before October 8 to 10 during very mild autunnis. 

 Wheat which has been j)lanted late enough to escape fall injury may, 

 however, become damaged in the spring if it is planted too near otlier 

 infested wheat. Deep plowing is also found to destroy a considerable 

 percentage of the insects. A number of insecticides were a})i)lied 

 ilirectly. It was found in these tests that dilute kerosene emulsion 

 and Bordeaux mixture are of some value, the former being the most 

 effective. Lime and Paris green in water, or dry lime alone, however, 

 j)rove(l to be useless. As a result of later experiments, it is stated 

 that no treatment is called for in controlling the Hessian fly provided 

 the wheat is planted at the proper time. When, however, the adult 

 insect invades wheat in the spring, it is sometimes necessary to apply 

 an in.secticide treatment. P\)r this purpose kerosene enuilsion is rec- 

 ommended, diluted at the rate of 1 part to parts of water. Applica- 

 tions of such an enudsion were made by means of a knapsack sprayer 

 in Octolx'r, March, April, and May, at the rate of lV.).i\ gallons of 

 kerosene per acre. The cost of this treatment, how(>ver, was found to 

 be greater than the extra yield of wheat thus obtained. A similar 

 treatment of lime and Paris green cost $8.0;") per acre, and of Bor- 

 deaux about $10 per acre. All these treatments prevented to some 

 extent the injury fronj Hessian fly, but their econimiy is still doubtful. 



In Missouri ^ the use of insecticides against the Hessian fly is con- 



a Kentucky Stu, Bula. 103, 111. » Missouri Sta. Bui. 63. 



