136 ANNUAL EEPOETS OF DEPARTMENT OF AGRICULTURE. 



epidemics. In the black stem-rust survey of the principal wheat 

 States, already mentioned, it is found that the barberry is rare in 

 Texas, Louisiana, Oklahoma, Missouri, and Kansas, and that even 

 where it does grow in these States rust is seldom found on it. Out- 

 side the spring-wheat area this shrub is of slight economic importance 

 from the standpoint of its probable relation to rust epidemics. Bar- 

 berry infections, however, are usually abundant in the spring- wheat 

 States. The eradication of the barberry in these States has been 

 recommended, and much has been done in that line. 



STRIPE AND BLOTCH DISEASES OF BARLEY. 



Extensive seed-treatment experiments conducted in cooperation 

 with the Wisconsin Agricultural Experiment Station at Madison 

 show conclusively that the stripe disease can be almost completely 

 prevented. At the same time, it appears that this disease is fully 

 as destructive to barley in that State as the barley smut. Additional 

 facts have been obtained concerning the relation of climate to the 

 infection of barley by the three fungi causing the stripe, spot-blotch, 

 and net-blotch diseases. 



PEAR-BLIGHT UPON PEAR AND APPLE. . " 



The great pear-blight outbreak which began in 1914 has been ma- 

 terially reduced as far as apples in the Eastern States are concerned, 

 but considerable attention has been devoted to service work in the 

 eradication of this disease and to cooperative work in Idaho and 

 Texas in controlling epidemics on apples and pears. 



CEDAR RUST UPON APPLE. 



The complete success in controlling cedar rust by the eradication 

 of the red cedars has been a marked feature of this work in the 

 large commercial apple districts. Cedar rust still remains a serious 

 disease in many localities, particularly where orchards do not form 

 a dominant part of the plant industry. While there are certain 

 phases of this subject that require further investigation, the main 

 problem may be regarded as definitely settled. Whenever it is de- 

 sired to control apple cedar rust in an apple-growing community, it 

 can be effectively and permanently accomplished by destroying the 

 red cedars in the winter. 



PECAN ROSETTE. 



Pecan rosette is regarded by the southern pecan growers as the 

 most serious menace to that industry. The work of this and previous 

 years indicates that the disease is not caused by parasites or other 

 organisms but is a nutrition trouble induced by deficiency in soil 

 moisture and plant food. Experimenting along this line, the disease 

 has been practically eliminated from a large number of trees on the 

 test plats. Results of a striking character have been obtained in the 

 experiments for controlling this disease. 



ANTHRACNOSE, OR WITIIER-TIP, OF CITRUS. 



Experiments in control have been continued on limes in southern 

 Florida, with successful results, these being the first definite results 



