October, '22] hayes: sorghum insects 353 



sorghum by another species of the same genus, Leptoglossus phyllopus 

 Linn. 



Angoumois Grain Moth. — The granary pest, Sitotroga cerealella 

 OHv. was unusuahy abtmdant in sorghum fields during the 1921 growing 

 season, causing considerable damage to all varieties of sorghums, and 

 much loss can be expected in the stored crop. Injury to sorghums 

 in the field is quite similar to that of other grains. 



Insects Attacking the Stalks and Leaves 



Chinch Bugs. — Sudan grass is reHshed by chinch bugs {Blissus 

 leucopterus Say) and many bugs seek their winter quarters at the crown 

 of the plants. An effort was made during the winter of 1920-1921 to 

 ascertain whether Sudan grass offered favorable protection for the 

 bugs. Accordingly, cormts were made during the fall and winter in 

 clumps of Sudan grass in which the stalks had been cut and in clumps 

 with stalks left standing. No noticeable difference was observed between 

 the cut and uncut as a means of protection. Owing to the mild winter 

 and comparative scarcity of bugs, counts did not show large numbers 

 in the clumps. During October, as high as 19 bugs were noted in 

 individual climips; in November, as many as 27, and 17 in Februar}^ 

 Chinch bugs were more numerous the past summer (1921), and counts in 

 November showed as many as 74 bugs to a clump. 



Observations were made on the susceptibility of milo to chinch bug 

 injury. To some it is a matter of common observation that young 

 milo plants are more seriously injured by chinch bugs than any of the 

 sorghums. Counts were made on the Kansas Experiment Station 1921 

 crop of sorghums. In the variety tests, out of 24 varieties, only three — 

 Dwarf Yellow Milo, White Milo, and Progressive Kafir — showed dwarf- 

 ed, stunted plants caused by bug injury, although many of the other 

 varieties showed some injury to the lower leaves. 



In these plots. Dwarf Yellow Milo exhibited the most injury, followed 

 by White Milo and Progressive Kafir in the order named. In the breed- 

 ing plots, White Milo showed as high as 25 per cent (by count) of injury 

 per row, while Dwarf Yellow Milo showed only 20 per cent. Two in- 

 teresting points were noted in this plot. Milo crosses in rows adjoining 

 the injured milo plants were untouched by the bugs and showed luxuriant 

 growth, attributed by plant breeders to what is known as 'hybrid vigor.' 

 Some plants of volunteer corn growing between the rows of injured milo 

 had but few bugs on them, and showed no damage, indicating that the 

 bugs in this case preferred the milo to com. 



