OBSTRUCTIONS TO DEVELOPMENT 



123 



4. Insects. — The Flea-beetle {Crepidodera {Epi- 

 trix) cucumeris) (Fig. 39). — These small inse(fts often 

 cause more loss than the potato 

 beetles. They perforate the 

 leaves (Fig. 40) during a critical 



FIG. 39 — THE CL'CUMBKR 

 FLEA-BEETLE {CrcpidoJiia 



(^Epitrix) cucumeris) 

 (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 ^^^ 4o-leaklet of potato, show- 

 spores of both early ing over a hundred holes made 

 and late blight for by flea-beetles 



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



, . . . . . overlooked is evident. These holes make 



/vrsenicai poisoning is suitable avenues for the entrance of spores 



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

 , . p destruction of the plant. 



on the margins or 



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



insecfts be readily destroj'ed. They dislike Bordeaux 



