BUREAU OF PLANT INDUSTRY. 203 



be distinguished by their action on Mtirquis wheat alone. Up to date, 

 at least 22 distinct forms have been identified. Some of these occur 

 commonly over rather large areas, while others are less common and 

 occur in restricted districts. These facts explain why a certain va- 

 riety of wheat may be resistant to rust in one place and not in another. 

 Investigation shows that these rust forms apparently do not change 

 their characters rapidly, so that after a variety of wheat resistant to 

 a ceitain form is developed it will remain resistant to that form. 



BARBERRY ERADICATION. 



The campaign for the control of the black stem rust of wheat by 

 the eradication of the common barberry, begun in the spring of 1918, 

 is now in its third year. Included in the area are 13 of the Xorth- 

 Central States, naniely, Colorado, Illinois, Indiana, Iowa, Michigan, 

 Minnesota, Montana, Nebraska, North Dakota. Ohio, South Dakota, 

 Wiscimsin, and Wyoming. vState laws requiring the removal of com- 

 mon barberry bushes have been enacted in all of tliese States except 

 Wyoming. The campaign is conducted in cooperation with the State 

 agricultural college in each of the States and with the State depart- 

 ment of agriculture in many of them. The different phases of the 

 campaign, namel}'^, education, location, and eradication, have been 

 continued in each State. 



LOCATION SURVEY. 



In a systenuitic bur\ey of cities and towns 168,478 bushes were 

 located on 12,8&C) private and public premises during the year. 

 Survey of nearly all cities and towns of over 300 population has been 

 c^mjileted. An intensive farm-to-farm survey is being carried on. 

 This has proved to be the largest and most important part of the cam- 

 paign. In the counties covered at least 20 farms per county have had 

 cultivated barberries. In approximately 50 counties all rural prop- 

 erties have ])een inspected; 1,81)7,374 bushes were located on 4,394 

 rural properties. In visiting these properties 129,850 miles of coun- 

 try road were traversed. The location of escaped barberries in Avood- 

 lands and pastures is a large problem. In the past year 1,674,034 

 escaped buislies were found scattered over 1,142 properties. 



Along with the original survey a resurvej' is conducted in order to 

 determine wliat bushes have not been removed in accordance with 

 notices served on owners and to determine where sprouts have devel- 

 oped from roots of buslies that were not properly dug, or seedlings 

 lia\e grown from berries and seeds scattered in digging or by birds. 

 In this resurvey 123,246 bushes and 24,000 sprouts were found remain- 

 ing on 1,614 properties. Most of these have been removed since. A 

 second resurvey is essential, and a third is sometimes necessary to 

 mak'c absolutely sine that no bushes are left. 



KRADICATION. 



Of 2,065.891 bushes found on 17.203 properties during the past 

 yeai- 1,994.366 were reported removed from 12,618 j)roperties. Dur- 

 ing the early days of the campaign ap))roximately 1,400.000 Inishes 

 Avei-e remoA-ed from nurseries, parks, railway rights of way, and 

 other public and private properties by means of publicity and other 



