DISEASES OF PLANTS. 351 



pecially during June, coupled with tlie prevalence of an optimum temperature 

 for the germination of the spores. 



The red leaf spot of grapes and its control, DtJMMLER (Wchnbl. Landio. 

 Vcr. Baden, 1910, p. Jil5; ahs. in Ztschr. Landiv. Versuclisw. Osterr,, 13 {1910), 

 No. 6, p. 597). — It is claimed that an early spraying with a 2 per cent Bordeaux 

 mixture before the disease appears will prevent it, and that if the disease has 

 already appeared, spraying will put a stop to further injury. The injury can 

 also be lessened by improving the soil conditions. 



Note on coffees resistant to Hemileia vastatrix, P. Dussert {Agr\ Prat. 

 Pays Ghaiids, 10 {1910), No. 91, pp. 337, 338).— An account is given of observa- 

 tions on a number of species of coffee cultivated in Madagascar, some of which 

 seem more or less resistant to the coffee leaf rust {H. vastatrix) . Among the 

 forms which are somewhat resistant are Coffca congensis chalotii, C. canephora 

 opaca, and 0. javanica. The author states that unlike the Liberian coffee the 

 quality of the beverage produced from the Madagascan berry is very agreeable. 



The bud rot of palms in India, E. J. Butler {Mem. Dept. Agr. India, Bot. 

 Ser., 3 {1910), No. 5, i)p. 221-280, pis. o, map 1, fig. i).— The author discusses 

 the history of the bud rot of palms, the area affected, the first appearance and 

 spread of the disease, the species of palm attacked, the seasonal prevalence, 

 symptoms, and characteristics of the causal organism, and measures for con- 

 trolling the disease. 



It is claimed that the special bud rot under discussion is caused by Pythium 

 palmivorum (E. S. R., 20, p. 454), a fungus parasite which attacks principally 

 the palmyra palm {Borassus flaiellifer) , and has caused the death of thousands 

 of trees in the Godavari and Kistna districts since its first ai>pearance in 1S90. 



The spores of the fungus are usually found between the soft inner leaf 

 sheaths, and are therefore not readily disseminated by the wind. The chief 

 agency in spreading the disease is supposed to be the palm climbers, who, while 

 gathering the leaves for thatching or tapping the trees for toddy and jaggery 

 (raw sugar), carry the fungus from diseased to healthy trees. Insects or 

 other animals may also aid in its dissemination, especially the rhinoceros beetle 

 and the palm weevil. 



Four species of palms are common in the Delta, viz, the palmyra {B. flabel- 

 lifer), the coconut {Cocos nucifera), the areca {Areca catechu), and the date 

 {Phoenix sylvestris). Of these, the first three are subject to the disease, while 

 the date is apparently immune. The palmyra palm is more subject to attack 

 than the other two, because it is the one climbed most frequently, and is there- 

 fore oftener infected. For the same reason the disease is far less common on 

 seedlings and young trees of the palmyra than on mature trees which are large 

 enough to be climbed regularly. 



The disease is usually confined in its earlier stages to the large, fleshy leaf 

 sheaths just below the expanded crown 6f leaves, and is not observable as a 

 rule until the fungus reaches the young soft tissues of the unexpanded leaves, 

 where it spreads rapidly and soon destroys the center of the bud. The cluster 

 of partially expanded leaves in the center of the crown is next affected, causing 

 the central sheath to wither, which is usually the first external indication of 

 the disease in standing trees. The affected leaves turn pale, wither, and finally 

 become dry and yellowish brown in from 10 to 12 days. 



Systematic cutting and destruction of all diseased trees is the only remedy 

 found of value in combating the disease. 



The rot of roses, J. Beauverie {La Pourriture des Roses. Lyon, 1910, pp. 8, 

 flgs. 5; reprint from Les Amis des Roses, 1910, Juhj-Aug.). — The author de- 

 scribes the symptoms of this disease, its cause, and the microscopic character- 



