DISEASES OF PLANTS. 875 



tioii (if wild poppy, wild oats, wild onion, and the annual chrysanthemum. In the 

 experiments for wikl poppy eradication, spraying with copj)er-sulphate solutions was 

 again tried. Shortly before the poppies came into flower they were sprayed with a 

 2 per cent solution. In one case the solution was distril)uted over the U])per side oi 

 the leaves, while in the second an attempt was made to thoroughly si)ray it on the 

 under side of the foliage. "When copi)er-sulphate solution was ajjplied so as to well 

 cover the under side of the leaves tlu' i)huits were to a great extent destroyed. 



The exi>eriments for wild oats eradication consisted of a top-dressing of nitrate of 

 soda and sulphate of ammonia. In 1901 the effects of basic slag and lime were tried, 

 the wild oats Ijeing sown with barley. The slag did not seem to produce any ben- 

 efit, but with the application of lime there was a marked reduction in the wild oats 

 and an accompanying increase in the barley crop. 



For the eradication of the wild onion a 5 per cent solution of carbolic acid was 

 tested with promising results. In the experiments for the eradication of the annual 

 chrysanthemum, the application of lime was tested at the rate of 2 tons per acre. 

 The application was followed by a decided reduction in the amount of wild chrysan- 

 theiiuuns present, but the results were not sufticiently marked to lead to the conclu- 

 sion that a single application of lime at the rate indicated would be sufficient for the 

 eradication of this weed. 



DISEASES OF PLANTS. 



A few common plant diseases in Delaware, C O. SMrrn [Delaivdre Sta. Bid. 

 6S, jip. 19-2S, 2)ls. o, Jig. 1). — Notes are given on corn blight, Lima bean mildew, 

 bean anthracnose, and bean and watermelon anthracnose. During 1903 many com- 

 plaints were received at the station regarding the blighting of corn. Investigation 

 showed that the trouble was due to the fungus Helminthosporium inconspicuum, which 

 })roduces discolored elongated spots on the leaves, the width often being limite<l by 

 the veins of the leaf. The fungus makes its appearance ordinarily during July and 

 August, and thus far has not been reported as injuring corn seedlings. The spore 

 characters and germination are described, and the results of some artificial infection 

 experiments are given. 



In many resi^ects this disease is said to resemble a destructive disease of maize in 

 southern Europe, which is attributed to H. turcicum, and the 2 organisms are described 

 as probably identical. As this disease occurs upon the corn in an advanced stage of 

 growth there appears to be no practical remedy for its prevention. Rotation of crops 

 is recommended, and as it is probable that spores would live after passing through 

 the alimentary canal of animals, the use of manure from corn-fed animals on land 

 intended for corn is cautioned against. 



The mildew of Lima beans due to Phytophihora phaseoli is described. This disease 

 seems to be entirely confined to the lima bean, and has l)een the subject of con- 

 siderable investigation at different stations. Hitherto the fungus has not appeared 

 in sufficient abundance to be very troublesome, but a warning is given for the pro- 

 tection of fields in case of a wet summer and fall. 



The bean anthracnose {Colletotrichum lindemuthianum) is described, the spore 

 characteristics, mycelium, etc., being characterized. On account of various experi- 

 ments which have been carried on to prove the identity of similar diseases, the 

 author gives an account of inoculation experiments between the species of Colleto- 

 trichum growing on the bean and watermelon. These inoculations were made with 

 spores on cucumber, jiumpkin, squash, muskmelon, watermelon, and bean, and 

 while the results are not considered conclusive, the failure to produce the disease 

 leads the author to believe that the two fungi are distinct, C. lindemuthianum grow- 

 ing on the bean and C. lagenarium upon the cucurbits. For the prevention of this 

 disease spraying with Bordeaux mixture has given satisfactory results. 



