DISEASES OF PLANTS. 689 



is of bacterial origin and due to tlie same organism as that causing the fire blight of 

 pears. The detailed results of his experiments are given. As preventive treatment 

 the author suggests the pruning of the diseased portions of the trees and attention 

 given to prevent infection being carried from one tree to another. 



Collar rot of citrus trees [Jnur. ./(unaicaAgr. Soc, 7 [1903), No. 11, pp. 435-438). — 

 A description is given of a disease of citrus trees attributed to Fii.'ii.sporium I'nnoni. 

 This disease may be recognized by an exudation of gum at the collar of the plant, 

 the de(;ay of the bark in patches, and the subsequent disagreeable odor, as well as 

 by the unhealthy ajipearance of the foliage and the death of the small shoots. The 

 effect of imperfect drainage, close planting, improper jjropagation, etc., as contrib- 

 uting to this disease are described, and various methods of prevention are given. 

 Based upon experiments which have been conducted in Florida, the author recom- 

 mends washing the trees with solutions of sulphurous acid, carbolic acid, or a sulphur 

 wash, a formula for which is given. 



Canker in cacao {Jour. Jamaica Agr. Soc, 7 [1903), No. 11, pp. 450, 451). — Based 

 njiou successful practice in Ceylon, rules are given for the prevention of canker in 

 cacao, which include the thinning (jf shade so that sun and air can reach all parts of 

 the trees, the destruction of all diseased parts, and careful attention to the subsequent 

 development of the trees. 



Pests of orchard and fruit garden, M. C. Cooke {Jour. Roy. Hort. Soc. ILondon}, 

 28 {1903), No. 1-2, pp. 1-44, pis. 3, figs, i (9).— Descriptive notes are given of a large 

 number of diseases of orchard and garden fruits and, so far as known, methods of 

 treatment are suggested. 



Root diseases of fruit and other trees caused by toadstools, C. Y. Piper and 

 S. W. Fletcher ( Wusliingtou Sta. Bnl. 59, pp. 14,figs. 5). — According to the authors, 

 the prune growers of Washington have suffered severe loss by the deatli of their trees, 

 and an examination showed that the injury was quite similar to that observed in 

 young orchards after a hard winter. The trees bore the appearance of having been 

 frozen, the inner bark being killed at the collar of the plant. An examination of 

 specimens showed, however, that the trees were infested with rhizomorphic strands 

 of a fungus, which was later determined to be Armillaria mellea. The effect of this 

 fungus on the tree as shown by the appearance of the leaves, roots, and trunks is 

 described. A careful examination of the diseased trees shows the presence of the 

 black strands just beneath the ground, and later the fruiting stage or the mushrooms 

 appear. 



The extent of injury due to this fungus is indicated in statements maile regarding 

 the losses in a number of orchards, nearly one-half the trees in one orchard having 

 died within the last few years. A brief description is given of the fungus and its 

 distribution. With a single exception, it has only been observed to attack prune 

 trees. As the disease has not a wide distribution, the authors suggest the pruning 

 of all diseased trees and care in subsequent planting. The trees should be kept in a 

 healthy, vigorous growth by good culture, and under no circumstances should the 

 mushroom form be allowed to be produced on the trees, as it is tiirough these that 

 the wide distribution of the disease takes place. 



A second form of root disease is described, which is attributed to another form of 

 Aniiil/aria mellca which attacks wild cherry, crab ajaple, majjle, and fir trees. This 

 fungus differs from the previous one in the bulbous enlargement of the base of the 

 fruiting form. The injury caused by this rot ia not as severe as that previously 

 described, and at present no serious loss is anticipated from this source. A technical 

 description of the fungus is given. 



A leaf-curl disease of oaks, E. M. Wilcox {Alabama College Sta. Bui. 126, pp. 

 171-187, pi. 1, fig>:. 3). — This l)ulietin is designed to call attention to one of the fungus 

 diseases of oak trees that threatens to di'stroy many of these trees, particularly in 

 cities and towns. The disease makes its aj)pearance early in the spring before the 



