OBSTRUCTIONS TO DEVELOPMENT 



I2 3 



4. Insects. THE FLEA-BEETLE (Crepidodera (Epi- 

 trix} cucumeris} (Fig. 39). These small insects often 

 cause more loss than the potato 

 beetles. They perforate the 

 leaves (Fig. 40) during a critical 



FIG. 39 THE CUCUMBER 



FLEA-BEETLE (Crepidodera 

 (Epitrix) cucumeris} 



(After Chittenden) 

 Highly magnified. The insect j 

 is barely one-eighth inch long. , 

 The damage done by this in- . 

 sect is considerably under- 

 estimated. 



period of the plant's 

 life. The holes pro- 

 duced are used by the FIG 40 _ LEAFLET OF POTATO , SHOW . 

 spores of both early ING OVER A HUNDRED HOLES MADE 



and late 



for 



BY FLEA-BEETLES 



blight 



entrance into the leaf. The ease with which this damage might be 



.... overlooked is evident. These holes make 



Arsenical poisoning IS suitable avenues for the entrance of spores 



USUally first noticed of disease, and pave the way for the rapid 



.. destruction of the plant. 



on the margins of 



these holes. At no time in their life history can these 



insects be readily destroyed. They dislike Bordeaux 



