90 INJURIOUS INSECTS OF 1904. 



and 87 show the Cyclone Dust Sprayer in operation, Fig. 86 repre- 

 senting the hand machine, and Fig. 87 the larger machine used on 

 wagon. Mr. Mohl sprayed twice with the "Caustic Lime" mixture, 

 and once with the "General Formula." At the date of my visit, 

 in July, the trees were looking very well, though they were not 

 free of leaf hoppers. He is of the opinion that if he had begun 

 earlier, "before the hoppers appeared" as he expressed it, and sprayed 

 three times, he could have kept them well under control. While the 

 writer is quite willing to be convinced, he has not absolute con- 

 fidence in the perfect efficacy of dust spraying. For many fungus 

 diseases and some insects, and under certain conditions where liquid 

 cannot be used, it is unquestionably an excellent thing, as shown by 

 the vigorous appearance of Mr. Mohl's trees, but in the case of the 

 leaf hopper we have doubts. We would be very glad indeed to 

 have these doubts removed, and its extreme usefulness demonstrated. 



Mr. Mohl is an enthusiast as regards dust spraying, as shown 

 by the following extracts from letters from him, the first written 

 on February 24th, and the latter, referring to the effect of spraying 

 his orchard, on July 25th. 



"I have your favor of the 23rd inst. regarding campaign against 

 the leaf hopper and was glad to hear from you on this subject as 

 I have for years been bothered with these leaf hoppers not only in 

 the orchard but also in the nursery. With the old method of spray- 

 ing, it has been hard to reach them as they get on the under side 

 of the leaf, which curls up and with liquid spray you cannot get to 

 them, unless, perhaps, by persistent early spraying, which may keep 

 them away. This year I intend to give the dust spray a thorough 

 test and will begin the first spraying before the leaves come out. I 

 intend to buy another small dust sprayer in addition to the Cyclone 

 sprayer which I have. This smaller machine can be carried about 

 and will come handy to fight the enemy as it appears. I shall also 

 buy the prepared dust as per circular which I enclose. 



"In the orchard where we sprayed with the Caustic Lime twice 

 and once with the General Formula, we can find scarcely any leaf 

 hoppers, and, in fact, no insect pest of any kind. I am of the opinion 

 that if we had begun spraying in the nursery before the enemy 



Note. — The "r'austic Lime" formula consists of ground lime, sulphur and 

 concentrated lye. The "General Formula" is made of ground lime, "sal. 

 Bordeaux," sulphur and Paris green. 



