500 Report of the Department of Entomology. 



adverse conditions of 1913. The chief fault with much of the 

 spraying by farmers against the cabbage aphis is the tendency to 

 hurry with the job and to use the spraying mixture too sparingly, 

 which makes for faulty treatment and is liable to result in 

 d isappointing returns. 



selection of spraying machine. 



Spraying machines especially constructed for the treatment of 

 large fields of cabbage have not yet appeared on the market, which 

 forces growers to adapt for this purpose the common types of 

 spraying outfits that they possess. The most satisfactory machine 

 is a gasoline-power field potato-sprayer, with the usual spraying 

 spar removed, and equipped instead with two leads of hose with 

 short extension rods bent at the nozzle end to form an angle. Its 

 chief merits are power to maintain uniform pressure and the pos- 

 session of axles which may be adjusted to the width of the rows, 

 thus reducing injuries to the cabbages by the wheels of the 

 machine during the progress of spraying and in turning on the 

 ends of the rows. In the Station's experiments a "horse-power" 

 or traction field potato-sprayer with a pump of large capacity and 

 equipped with two leads of hose, as with the foregoing outfit, has 

 given excellent satisfaction in fields moderately infested with the 

 lice. By limiting each operator of the nozzles to two rows of 

 cabbages it has been possible to spray practically all of the plants 

 needing treatment. Machines that are more commonly relied on 

 by growers are orchard power-sprayers and barrel outfits mounted 

 on a single- or two-horse truck. These have been used with good 

 effects against the aphis, but with many of them, on account of 

 the width of the axles, cabbages are damaged by the wheels unless 

 at the time of planting provision is made for a suitable spacing 

 of certain of the rows to accommodate the spraying outfits. Trac- 

 tion field-sprayers with fixed nozzles are not well adapted for the 

 treatment of cabbages as many of the insects are not wetted by the 

 application. For spraying a small plat a knapsack sprayer is a 

 convenient and quite satisfactory outfit. 



