April, '17] KELLY: GREEN-BUG OUTBREAK 239 



west and kept in breeding cages for parasites, Aphidius testaceipes, 

 which were reared from nearly every locahty. 



During the winter of 1915-1916 we had several freezes, the ther- 

 mometer going as low as nine degrees below zero. Investigation dm-ing 

 the winter indicated that the insect was Uving in the wheat stubble 

 fields, along the protected fence rows, hedges, especially in rank wheat, 

 and many of them crawled under clods. The weather warmed up 

 rather earlyinMarch, 1916, with 80 to 90 degrees temperature during the 

 last ten or fifteen days. The Toxoptera came from their hiding places 

 and began to breed freely on the wheat. Our observations at that time 

 showed that they were present in practically all of the thick growing 

 wheat, the thin wheat not being infested. During March and April 

 oats were planted in abundance, practically the largest acreage ever 

 sown in southern Kansas and northern Oklahoma, because the wet fall 

 of 1915 prevented seeding the land to wheat. By the middle of April, 

 oats were sprouting and coming up from southern Oklahoma to cen- 

 tral Kansas. The weather remained cool during this time, and Toxop- 

 tera continued to breed freely on the wheat. About the last week of 

 April they began to migrate from the wheat to the oats, and by the first 

 day of May it was not difficult to find the winged forms and small 

 colonies on practically all of the oat plants throughout this territory. 



Outbreak Imminent 



The outbreak of 1916 began in the spring of 1915. As indicated by 

 the above report, this insect is practicallj' present at all times in some 

 of our fields, more or less abundant, and ready to increase with the 

 slightest favorable opportunity. In 1915 they were observed almost 

 everywhere an entomologist who was interested in the species visited 

 and looked for them. The cereal and forage crop entomologists of the 

 Bureau of Entomology' were observing them from South Carolina, 

 across the continent through Tennessee, Missouri, and Texas, to New 

 Mexico. The favorable conditions through June, July, August, Sep- 

 tember, and October of 1915, with its abundance of volunteer wheat 

 and volunteer oats throughout all of the western states, extending from 

 north central Texas to Nebraska, gave them the most excellent 

 opportunities for establishing themselves. As fall approached, the 

 farmers were asking if we were to have an outbreak of "green bug." 

 Our one answer was, we cannot say, because we do not know what the 

 spring will bring us, nor what the winter will do for the insect. 



Investigation in December in northern Texas, by Mr. C. L. Scott, 

 indicated they were rather plentiful northwest of Fort Worth, in the 

 vicinity of Bowie and Ballinger, where there was an abundance of oats 



