THE GKAIIST BUG. ' 33 



HAND PICKING. 



Hand picking of the grain bug adults and nymphs may possibly 

 prove practical when valuable crops growing on small areas are at- 

 tacked. These conditions often occur in the high-priced irrigation 

 areas of the Southwest. 



HOPPERDOZERS. 



It has often been suggested that a hopperdozer might be employed 

 to collect the adults and nymphs of the grain bug while they are feed- 

 ing on the heads of the grain. An operation of this kind, however, 

 would be complicated by the fact that the insects generally drop to 

 the ground when closely approached. Then, too, at the time when 

 most of the injury by the grain bug occurs the condition of the grain 

 is such that the passage of any collecting machine would result in 

 considerable damage to the crop. 



A modification of the hopperdozer might be effective when the at- 

 tacked crops are grown in hills or rows. 



ASSOCIATED SPECIES OF PLANT BUGS. 



A few nymphs and adults of Thyanta custator Fabr., Thyanta 

 rugulosa (Say) UliL, and several species of the genus Euschistus gen- 

 erally were found associated with Chlorochroa sayi in the field and 

 closeh^ resembled the latter in their life history and habits. None 

 of these species was present in sufficient numbers to cause apj^reciable 

 damage in the section of the countrj^ where these observations were 

 made. 



SUMMARY. 



1. Since 1911 the grain bug {CKlorochroa sayi Stal) has become a 

 serious enemy of wheat and other small grains in the intermountain 

 and southwestern States. 



2. The most important damage is caused by the insect piercing the 

 newly formed heads of various cereals and removing the liquid con- 

 tents, thus preventing the formation of the grain. or greatly reducing 

 its weight. 



3. The reduction in yield from grain-bug attack varies from 10 to 

 50 per cent of the crop. In extreme cases the entire crop may be 

 destroyed. 



4. The cultivation of large areas formerly devoted to grazing elimi- 

 nated the native food plants of the insect and caused it to attack cul- 

 tivated plants. 



5. This change to more succulent food plants, together with the 

 superior facilities afforded for hibernation in the cultivated areas, 

 resulted in an increase of the pest beyond its former abundance. 



