142 



INSECT PESTS OF FARM, GARDEN AND ORCHARD 



1890, 1901, and 1907, the temperature for the first five months of 

 each of these years, including the latter part of the winter and 

 spring, was above the normal for the winter months and below the 



normal for the spring months; in other 

 words, warm winters and cold, late 

 springs." 



" The little parasitic wasp which is 

 so useful in the control of this pest is 

 native to this country, widely dis- 

 tributed, and every year does its work 

 with the ' green bug ' and with other 

 aphids. It is always present in grain 

 fields, as shown by its appearance 

 every year, tc war on these pests when- 

 ever the weather conditions make 

 its breeding and multiplication pos- 

 sible, and its rate of breeding is so 

 rapid (there being a generation about 

 every ten days) that with a week or 

 two of favorable weather it gains con- 

 trol over its host insects and destroys 

 them.* 



Control. Most important of all 

 methods of control is the abandonment 

 of the growing of volunteer oats and 

 the destruction of all volunteer oats 

 and wheat in the early fall. Uni- 

 versal experience throughout the in- 

 FIG. 123. Parasitized green jured area shows that relatively little 



b raVlte g S d i ( HunteO t0 ~ in]ury occurs where volunteer oats 



is not grown. 



Where small spots of grain have been injured by the pest in late 

 winter, which is the way an outbreak usually begins in southern 

 localities, the aphids on these small spots may be killed by spray- 

 ing with 10 per cent kerosene emulsion, or whale-oil soap, 5 pounds 

 to a barrel of water, by covering the spots with straw and burning 

 or by plowing under the infested spots. Were this generally done 

 before the aphids commence to multiply rapidly, it is entirely 

 possible that widespread injury might be averted. 



* From F. M. Webster, Circular 93, Bureau of Entomology, U. S. Dept. Agr. 



