BUREAU OF PLANT INDUSTRY. 169 



active operation in thirteen North-Central States, namely, Colorado, 

 Illinois, Indiana, Iowa, Michigan, Minnesota, Montana, Nebraska, 

 North Dakota, Ohio, South Dakota, Wisconsin, and Wyoming. 

 State laws requiring the removal of common barberry bushes have 

 been enacted in all these States except Indiana, Ohio, and Wyoming. 

 The campaign has been conducted in each State by widespread pub- 

 licity through many channels. 



The first problem, naturally, is to locate all bushes resulting from 

 intentional planting and induce their owners to remove them. 



The second, and perhaps the most difficult problem in the cam- 

 paign, is to locate bushes running wild. The number of localities in 

 which wild bushes are found is immensely larger than was believed 

 at the beginning of the campaign. Through many decades since 

 barberries were first planted in these States, the seeds have been 

 sown in large numbers in thickets and woodlands by wild birds. 

 The difficulty of locating such bushes in rough and broken timber- 

 land, oftentimes amid thickets and underbrush, will be appreciated 

 by anyone who undertakes it. It is essential, however, that such 

 bushes be located and removed. In most cases they are not far 

 distant from grainfields, and in any case rust spreads readily from 

 them to grainfields by way of wild grasses in their vicinity. Further- 

 more, if they remain undisturbed their numbers will continue to in- 

 crease by the action of birds throughout the years to come. 



The third problem is to insure that every bush located is removed 

 by the owner or agent, and so thoroughly and completely removed 

 that sprouts will not develop, or, failing this, to insure that sprouts 

 which do appear will be destroyed. 



Already the number of bushes located and destroyed runs into 

 the millions. More than half a million have been destroyed by 

 nurserymen in a single State. Naturally, as the campaign progresses 

 the number of bushes located each month becomes smaller. How- 

 ever, they are still being found by the tens and hundreds of thou- 

 sands. From March to July, 1919, inclusive, more than 16,000 

 bushes were located in Illinois. Nearly 40,000 were located in Iowa 

 during the spring and early summer of this year. Up to May 30, 

 1919, Nebraska had found 63,000 bushes. About 91,000 plants have 

 been removed from private premises in Wisconsin, in addition to 

 large numbers taken out of public grounds. No serious outbreak 

 of black stem rust occurred this season, although many bushes un- 

 doubtedly remain undiscovered. 



LEAF RUSTS OF WHEAT, BARLEY, AND RYE. 



A leaf -rust survey and investigation of epidemiology have shown 

 the leaf rusts, and particularly the leaf rust of wheat, to be of far 

 greater importance as limiting factors in grain production than 

 had been supposed. In some sections of the South Atlantic coast 

 the damage due to the leaf rust of wheat was so serious as to ruin 

 the crop. In the States growing hard winter wheats extensively, 

 such as Kansas, Nebraska, and Oklahoma, leaf rust was almost 

 epidemic this season. 



Field, greenhouse, and laboratory investigations of the leaf rusts 

 of wheat, barley, and rye have been carried on in cooperation with 



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