ATTACKING SURFACE OF STALK OR STEM 



139 



Fig. 128. — The Rhubarb 

 Curculio. Slightly en- 

 larged. Original. 



three fourths of an inch long. It may be 

 controlled by hand picking. The normal 

 place of breeding is in the stems of dock, 

 and this weed should be removed from the 

 neighborhood of rhubarb. 



The Hessian-fly (Mayetiola destructor Say) 



Few insects have wrought greater dam- 

 age than this pest in its periods of 

 abundance. It is one of the prime enemies of our wheat-growing regions. 

 The adult is a tiny, two- winged gnat, one tenth of an inch long. It 

 emerges in the fall, at the time that winter 

 wheat is just unfolding its leaves, and laj^s eggs 

 on the upper surface of the leaves. The re- 

 sulting maggot goes down to a point within 

 the leaf sheath, feeds, and later transforms 

 to a small, hard, brown object looking like a 

 seed, and known as 

 the "flaxseed." In 

 spring a new lot of 

 adults emerge from 

 these ''flaxseeds," 

 and at once lay eggs 

 on the leaves of the 

 young wheat as be- 

 fore. The maggots 

 which hatch from 

 these eggs feed at the 

 base of the leaf, caus- 

 ing characteristic in- 

 jury. An infested 

 plant is stunted, 

 shows no visible stem, and is darker than normal in color. If the 

 infestation is severe, the plant is seriously injured or entirely destroyed. 

 The summer is passed in the flaxseed stage, in the wheat stubble. 



Fig. 129. — ^^■..I■k and 

 pupariaof the Hessian- 

 fly. Original. 



Fig. 130. — Adult of the 

 Hessian-fly. Enlarged 

 and natural size. Orig- 

 inal. 



