180 THE BOOK OF WHEAT 



REMEDIES. Several methods are quite effective in bringing 

 about the destruction of locusts. They have many natural 

 enemies, such as parasitic fungi and insects and birds. These 

 should be protected. Experiments have been made by intro- 

 ducing fungi, especially from South Africa. They were arti- 

 ficially spread, but with little success. Deep fall plowing for 

 the destruction of the eggs is perhaps the best remedy known. 

 In western Colorado "ballooning" used to be practiced. The 

 insects were caught in a large open sack by riding a horse 

 rapidly across the field. A bounty of one cent a pound was 

 paid for the insects, and the rider earned from $5 to $10 per day. 

 Undoubtedly the most effective remedy after the locusts are 

 hatched is to scatter bran or horse droppings poisoned with 

 Paris green around the field before the locusts have entered it. 



In Argentina the best 

 results were attained "by 

 the use of torches dipped 

 in tar." The great abun- 

 dance of locusts in cer- 

 tain years is doubtless the 

 result of a coincidence 

 of climatic conditions fa- 

 vorable to their develop- 

 SPRING GRAIN-APHIS OR GREEN ment and the absence to 

 BUG. ENLARGED a great degree of natural 



destroyers. 



The Spring Grain Aphis (Toxoptera graminum Rond). This 

 species, popularly called the "green bug," was first described 

 in 1852, and 30 years later it was discovered in America. It is 

 found most abundantly in the southwest. This pest can be 

 found in the wheat fields during any year, throughout the in- 

 fested region, but it is rather erratic in its outbreaks. In ordi- 

 nary seasons it is held in check by its natural enemies. It is 

 extensively parasitized, and lady beetles devour both young and 

 old. It can withstand a lower temperature than its enemies, 

 however, and outbreaks occur after a mild, open winter fol- 

 lowed by a late and wet spring. Such outbreaks occurred in 

 1890, 1900 and 1907. In the south it may breed all winter, and 

 It has an enormous rate of increase. The eggs are laid among 

 the grain plants in the fields. Wheat and rye are the chief 



