BUREAU OF PLANT INDUSTRY. 153 



should be made to salvage the great quantities of spoiled stock now 

 rejected and dumped at our terminal markets. 



PLANT PATHOLOGICAL INVESTIGATIONS. 



BARBERRY PLANTS AND BLACK STEM-RUST OF WHEAT. 



The campaign for the control of stem-rust of wheat through the 

 eradication of the common barberry has aroused a widespread and 

 effective sentiment against the shrub. This has resulted in the re- 

 moval of the following estimated percentages of the plants located by 

 the survey: Northern Illinois, 60 per cent; Wisconsin, 90 per cent; 

 Minnesota. 80 per cent ; North Dakota, 90 per cent ; South Dakota, 80 

 per cent; Nebraska, 75 per cent; and Iowa, 75 per cent. The work 

 has been well begun in the States adjoining tliose named. Safety lies 

 only in the complete eradication of the common barberry plant. 



RECENTLY DISCOVERED DISEASES OF CORN. 



Work on the Physoderma disease of corn has shown this to be of 

 economic importance in the more humid parts of the South Atlantic 

 and Gulf Coast States. Study of the life history and distribution of 

 the causal organism has been completed, and the results have been 

 prepared for publication. 



The study of the root rots and ear rots of corn has resulted in the 

 isolation of several soil-infesting fungi which infect the corn plant. 

 These organisms, producing rots in both root and ear, have been 

 proved more or less active in causing low yields. One of the most 

 virulent of these has been discovered to be identical with the fungus 

 which causes scab of wheat, oats, barley, and rye. 



SMUTS OF CEREALS. 



A nation-wide campaign for the control of cereal smuts has been 

 under way since September 1, 1917. Through cpoperation with the 

 States Kelations Service, thousands of farmers w^ere induced to treat 

 their seed grain in the fall of 1917 and the spring of 1918. During 

 the spring and summer of 1918 an extensive fielcl survey has given 

 much information on (1) the distribution of the various cereal smuts, 

 (2) the losses caused by them, (3) the extent to which farmers treat 

 seed grain to prevent smut, (4) a comparison of fields sown, respec- 

 tively, with treated and untreated seed, and (5) the economic im- 

 portance of other preventable cereal diseases. 



ROTS AND SPOILAGE OF SMALL FRUITS. 



Investigations of the rots and spoilage of strawberries, blackberries, 

 dewberries, and raspberries were carried on in the field and market 

 during the year. It has been found that a number of fungi may cause 

 decay of these fruits in transit and distribution. The principal or- 

 ganisms are Ilhizopus, Mucor, Botrytis, and Patellina. Studies of 

 the temperature and moisture relations of these fungi in relation to 

 the methods of picking, handling, and shipping have shown that the 

 losses from these causes can be very greatly reduced by picking the 

 fruit early in the day, even though wet with dew or rain. Careful 



97335"— AGE 1918 11 



