New York Agricultural Experiment Station. 611 



The gas treatment was tested during March, 1894, by the United 

 States Division of Entomology at Charlotteville, Ya., on trees in 

 orchard. A tent was used in this test, and the same amount of gas 

 used as recommended for citrus trees. This treatment was not a 

 perfect success. 



It is reported that Lovett & Co., of Little Silver, N. J., have used 

 boxes for fumigating with hydrocyanic acid gas all the stock infested 

 wliich they have sent out the past eighteen months. It was my 

 privilege to watch throughout the summer a lot of apple trees 

 which were purchased from Lovett & Co., April, 1895, by Mr. C. W. 

 Ward, of Queens, N. Y. This stock was supposed to have been 

 treated with gas, as it was evidently infested wnth the " Pemicious 

 Scale." At the time the first brood of the " Pernicious Scale "com- 

 menced to appear the above stock was carefully inspected and not a 

 tree was found that did not have young specimens crawling over 

 them. 



Although some results indicate that the gas treatment is not a 

 complete success, in most cases the failures can be traced to some- 

 thing which has interfered with its thorough application. Any 

 remedy will prove a failure when tested on the " Pernicious Scale," 

 unless care is taken to make the treatment thorough. Even whale- 

 oil soap will prove a failure in nursery unless dirt is removed from 

 base of the tree and the wash thoroughly applied to all jjarts. 



From the amount of stock which I have had the privilege of 

 inspecting, after treatment with gas and with whale oil soap, I think 

 it is safe to assert that, all things considered, the gas treatment is 

 the cheapest remedy for nurserymen who handle and ship fruit trees 

 in large quantities, and will be as effective as any remedy under 

 ordinary conditions of application. 



lloiv to Use the Fumigating Boxes. — Figure 2, Plate I, shows 

 a box tilled with trees, inverted and banked with dirt ready to have 

 the gas generators inserted. One generator will answer but two are 

 better. An ordinary glass fruit jar makes a good generator. The 

 fused potassium cyanide should be weighed and put into packages 

 containing the pro}>er amount required for each generator, so that 

 all the workmen will have to do will be to empty the package into 

 the generator after having placed it under the box. He should be 

 provided with two measures, one for the acid and one for water. The 

 acid and water should be put into the generator before the latter is 



