INSECTS INJURIOUS TO CUCUMBER, MELON, ETC. 167 



Bisulphid of carbon. — In small fields it is customary to cover 

 hills of melons as soon as the insects make their appearance 

 with a tub or similar receptacle, and evaporate beneath this 

 bisulphid of carbon at the rate of a drachm to a cubic foot or 

 less of space. A tablespoonful serves for ordinary tubs. This 

 does not injure the plant, and if the tub fits tightly to the 

 ground so as to retain the vapor of the bisulphid, the "lice ' will 

 all be killed. Large growers watch vines carefully, removing 

 and destroying affected plants as soon as noticed to prevent 

 spreading the trouble. 



Kerosene emulsion and soap solutions. — The melon aphis 

 could be more readily dealt with if it did not feed on the 

 under surface of leaves, and if vines like melons did not 

 grow so closely together as to interlace that spraying by 

 ordinary means is practically impossible. Under-spraying is a 

 necessity, and the sprayer used should be fitted with an up- 

 turned nozzle to secure this effect. 



Soap solutions, such as whale-oil, fish-oil and potash soap, 

 are not so useful. 



Clean farming zvith fall plozving should always be followed, 

 as it is a most valuable measure of prevention of attack by 

 aphides and other insects that are present. As soon as the crop 

 is off remnants should be gathered and burned, and all weeds 

 kept down until the fields are again planted, since, as has been 

 shown, common weeds of the field and garden serve as alter- 

 nate food plants, and are selected as hibernating quarters by the 

 "lice." 



Pyrethrum applied to the underside of the leaves with a 

 powder bellows is effective, but can not be used with profit on 

 large fields or on plants like squash with large leaves. 



Remedies that have been indicated as of service in the con- 

 trol of the melon aphis operate against many other insects 

 which are usually present at the same time. Thus the kero- 

 sene and soap solutions kill small squash bugs and act as 



