OBSTRUCTIONS TO DEVELOPMENT 



I2 3 



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

 trix) cucumeris) (Fig. 39). These small insedls often 

 cause more loss than the potato 

 beetlevS. They perforate the 

 leaves (Fig. 40) during a critical 



FIG. 39 THE CUCUMBKK 



FLEA-BEETLE (Crepidoilera 



(Epitrix} fitcurneris} 



(After Chittenden) 

 Highly magnified. The insect 

 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 

 spores of both early 

 and late blight for 

 entrance into the leaf. 



FIG. 40 LEAFLET OF POTATO. SHOW- 

 ING OVER A HUNDRED HOLES MADE 

 BY FLEA-BEETLES 



The ease with which this damage might be 

 A 1 overlooked is evident. These holes make 



Arsenical pOlSOnmg 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 



insecfls be readily destroyed. They dislike Bordeaux 



