46 



THE MEANS OF CONTROLLING PLANT DISEASES 



sprays there are little atomizers holding a quart or 

 two with which house plants, small gardens, or a 

 few cattle may be sprayed. Next come the bucket 

 pumps and knapsack sprayers, which will be found 

 useful on most farms for spraying small areas or 

 isolated trees in gardens. For several years barrel 



A modem spray tie, with mounted gasoline engine. 



pumps were much used in all spraying operations, 

 but now large tanks equipped with more powerful 

 pumps in which the power is developed by horses, 

 by steam or gasoline engines, by compressed air, 

 or carbonic acid gas, are mostly used in spraying 

 large areas of orchards, vineyards, potatoes and 

 other crops. The horse-power pumps, in which 

 the power is developed from the wheels by chain 

 or eccentric attachments as the machine moves, 

 give sufficient power to do satisfactory work 

 only on potatoes and similar low field crops. A 

 small compressed-air tank attached to these horse- 

 power pumps greatly increases their efficiency for 

 the spraying of small orchard trees and vineyards. 

 The pumps using compressed air for power do very 

 effective spraying of all kinds, but the necessary 

 outfit of several spray tanks, an engine and an air- 

 compressor are rather expensive. Steam spraying 

 rigs are heavy but are easily managed, and fur- 

 nish cheap and abundant power. Gasoline engines 

 are lighter and are being much used instead of 

 steam power. The tanks of compressed carbonic 

 acid furnish ample, easily manipulated but slightly 

 more expensive power than the engines. Some of 

 the forms of spray rigs are shown in Figs. 67-7L 

 Good nozzles are an essential part of spray 

 pumps. Several types of spray nozzles are used. 



Some, like the cyclone and Vermorel nozzles, pro- 

 duce a very fine, funnel-shaped spray. In another 

 type, like the McGowan, the spray is fan-shaped 

 and can be thrown farther. The various modifica- 

 tions of the Vermorel type of nozzle are now 

 most extensively used, often several nozzles being 

 grouped at the end of a light rod attached to the 

 spray hose. 



The manufacturers of spraying apparatus are 

 constantly improving and modifying their machines 

 so as better to adapt them to the practical needs 

 of the agriculturist. American farmers are un- 

 doubtedly the best equipped with insecticidal bat- 

 teries, and they are putting up the most scientific 

 and successful fight against their insect enemies. 



Literature. 



The literature on the means of controlling insects 

 is very extensive and scattered, much of it having 

 to do with controlling specific pests. The reader 

 ■"'ill find a great deal of interesting material in 

 )ecial articles in the yearbooks, in bulletins and 

 circulars of the Bureau of Entomology and 

 Farmers' Bulletins, of the United States De- 

 partment of Agriculture, and in bulletins 

 issued by the federal and state experiment 

 stations of the various states. The 

 following publications should also be 

 consulted: Annual Reports and Bul- 

 letins issued by the State Entomolo- 

 gists of New York (Dr. E. P. Pelt, Al- 

 bany), Illinois (Prof. S. A. Forbes, Ur- 

 bana) and Minnesota (Prof. F. L. Wash- 

 burn, St. Anthony Park, St. Paul), and 

 by the Government Entomologist (Dr- 

 J. Fletcher) at Ottawa, Canada ; Lode- 

 man, Spraying of Plants, 1896 ; John- 

 son, Fumigation Methods, 1902; 

 Smith, Economic Entomology, 1896 ; Weed, Insects 

 and Insecticides, 1895 ; Sanderson, Insects Injuri- 

 ous to Staple Crops, 1902. 



THE MEANS OF CONTROLLING PLANT 

 DISEASES 



By Henry L. Bolley 



Almost every farm, garden and orchard crop is 

 open to the attack or infiuence of one or more 

 kinds of infectious disease. As farming, garden- 

 ing, or fruit-producing districts age under cultiva- 

 tion, the soil ages, and the conditions and materials 

 that are favorable to the development of disease 

 accumulate. Each crop, or type of cultivated plant, 

 unless properly handled, becomes more and more 

 susceptible to disease, and is more liable to be 

 attacked by disease-producers that are natural to 

 the habits and growth conditions of that particular 

 kind of crop. 



Practically every known cultivated plant and 

 crop, including hothouse-grown plants, vegetables, 

 fruit and shade trees, grasses and cereals, is thus 

 attacked and the yield and quality are often greatly 

 reduced. It is to be expected that the warfare will 

 continue. 



