PEOGEESS EEPOET ON THE EUROPEAN CORN BORER 
63 
1 per cent of the plants were involved, but in extreme cases as high 
as 20 per cent of the plants contained the borer. In 1922 an inspec- 
tion was made in 30 of the larger greenhouses in eastern Massa- 
chusetts, where a total of 353,500 chrysanthemums were grown. 
Fig. 29.- 
borer. 
-Injury to stem and flower of greenhouse chrysanthemum by European corn 
Stem sectioned to show borers within. Melrose, Mass., November 10, 1922 
Infestations were found in 23 of these establishments, the number of 
plants involved ranging from less than 1 to 9.22 per cent, with an 
average of 1.08 per cent for the 30 houses, at the time of examina- 
tion. Many of the injured plants had been removed and discarded 
