INSECT PESTS OF OHIO SHADE AND FOREST TREES 193 



required the speeding of the engine and the overworking of the 

 pump, so that in reahty the machine was subjected to considerable 

 strain. Moreover, it was found to be difficult to keep everything 

 in perfect repair, such as the blowing out of cylinder packings, 

 bursting of hose, the giving way of connections, and the like. 



However, by giving the machine careful attention and the use 

 of a 10- or 12-foot extension rod, they were nearly able to reach the 

 topmost branches of the trees sprayed, none of which was over 75 

 feet tall. As stated previously, the results as a whole were mod- 

 erately successful, since the operators were able to spray tall trees 

 with a thoroughness and dispatch that would have been quite im- 

 possible by the mist method ; but it would be impracticable to oper- 

 ate any sprayer of the ordinary mist type continuously under the 

 strain to which these machines were subjected; and, if the solid- 

 stream method is to be employed regularly, one of the stronger, 

 heavy-duty machines should be secured for the work. 



One of the machines used in the work is illustrated running 

 under full pressure and delivering the spray in a solid stream in 

 Plate XV, Fig. 2, and with the supplementary M. A. C. nozzle for 

 making the flush spray in covering the lower limbs in Plate XV, 

 Fig. 1. 



CAN THE SOLID-STREAM MACHINES BE USED FOE MIST WORK? 



While the practicability of using the mist sprayers for solid- 

 stream work is perhaps doubtful, there seems to be no reason why 

 the solid-stream sprayers cannot be equipped with mist nozzles and 

 used for producing the mist spray. The foregoing statement is 

 not based upon the actual experience of the writer, and, to his 

 knowledge, the solid-stream sprayers of the eastern states are not 

 used for mist spraying because they are employed almost exclu- 

 sively in the application of poisons for leaf-eating insects during 

 the summer months. Under Ohio conditions, however, there is con- 

 siderable necessity for scale spraying, which must be done in the 

 spring before the leaves appear; and, in order to be effective, every 

 portion of the affected tree or shrub must be covered. The mist 

 type of spray is much better adapted and more economical for the 

 treatment of low-growing shrubs and trees in scale eradication; 

 hence the ability of the solid-stream machines to produce either the 

 solid stream or the mist spray, merely by a change of nozzles, 

 renders them especially qualified for city use. 



A SELF-PROPELLED SPRAYER DESIRABLE FOR CITY USE 



With the decrease in the use of draft horses for city hauling, 

 it is becoming increasingly difficult to secure the necessary teams 



