12 BULLETIN 808, U. S. DEPARTMENT OF AGRICULTURE. 



posed to be the only species present, and even tritici was considered 

 a varietal form of it. Harris (7) described this species in 1830. 

 Along in the twenties it caused such serious injury to barley in 

 Massachusetts that the growing of this crop was abandoned in some 

 sections. For years it was a scourge to barley-growing sections in 

 the East. The Eastern States have largely ceased growing barley 

 for a number of years now, and consequently have suffered very little 

 injury. The barley-growing section has moved west, Wisconsin, 

 Minnesota, and the Dakotas now being the most important barley 

 States. Fortunately Twrdei does not seem to have been introduced 

 artificially into those sections, which is the only plausible way it 

 could be transferred from the main barley section in the East. Bar- 

 ley, unlike wheat, is not grown generally in the intervening States, 

 so that there is no chance for hordei to spread gradually westward as 

 tritici seems to have done. 



During the late summers of 1913 and 1914 the writer visited por- 

 tions of New York State that were formerly great barley-growing 

 centers. Only a very few infested barley stubbles were found after 

 extended search in 1913, and none were found in 1914. Very little 

 barley is grown there now. The fields, as a rule, are widely sepa- 

 rated and the stubble usually is plowed under before hordei has had 

 an opportunity to emerge, consequently it has been almost extermi- 

 nated. This is one of the very rare instances of a once serious pest 

 becoming practically extinct. Its scarcity is such that the writer had 

 never seen a specimen of hordei until the spring of 1914, except the 

 few fragmentary specimens in museums. 



H. hordei has been confused with tritici and secalis undoubtedly, 

 and probably with vaginicola and others. As the coloration of the 

 legs of hordei varies to a considerable degree it is not surprising that 

 confusion arose years ago, since that was one of the main characters 

 used in identifying the species. 



MANNES OF INJURY. 



Barley plants are affected by hordei (PL IV, A) in exactly the 

 same manner as wheat plants are by tritici. In fact, but for the 

 slightly different appearance of barley straw from wheat straw, the 

 galls could not be separated once they became mixed. When barley 

 plants are badly infested galls may be found above every joint. 



HOST PLANTS. 



The writei has now oeen breeding hordei in confinement for 4 

 years and has never succeeded in inducing it to breed in any plant 

 other than barley. 



