ELM LEAF ROSETTE AND WOOLLY APHID OP APPLE. 337 



about 30,000; 45,000; and 300,000 trees, states that he found 

 from 20 per cent to 25 per cent of the trees infested by the 

 woolly aphid. 



In circular No. 20, Bureau of Entomology U. S. Department 

 of Agriculture (revised edition 1908) the woolly aphid of the 

 apple is characterized as "one of the worst enemies of the 

 apple." 



Mr. Alwood (1904) of the Virginia State Crop Pest Com- 

 mission in his excellent account of this insect states "On nur- 

 sery stock the woolly aphis is a most serious pest, and under 

 some circumstances it ruins a large percentage of the apple trees 

 in the nursery." 



On page 5 of Bulletin 133 of the Colorado Experiment Sta^ 

 tion the following statement is made : 



"If Colorado orchardists should vote their opinion as to what 

 ought to be called the worst orchard pest in the state, it is very 

 doubtful whether the codling moth, or the woolly aphids, would 

 carry off the honors." 



Although it would be easy to compile testimony of this char- 

 acter against the woolly aphid as an enemy to young apple trees 

 from numerous and widely separated parts of our country, they 

 would be chiefly a repetition of what has already been said. 



During those seasons when the species is abundant it is also 

 a serious pest on American elm. Some springs in the vicinity 

 of Orono practically every branch of many trees is tipped with 

 an unsightly cluster of deformed leaves or "rosette" gall. Such 

 an infestation, to say the least, mars the beauty of a large tree 

 and is a heavy handicap for a young one. 



