DISEASES OF PLANTS. 555 



grouped by Sadebeck into 3 genera, viz, Magnusiella, TapJirina, and 

 Uxoascus. In the present paper the author reports on the prunicolous 

 species, which, so far as known, all belong to the genus Exoascus. The 

 species of this genus have a perennial mycelium, and a new infection 

 each year is secured by the mycelium wintering in the tissues of the 

 host and by spores. 



Definite and conclusive experiments have not yet been made concern- 

 ing the treatment and the control of the disease caused by the various 

 species of Exoasccw. On account of the i)erennial mycelium, a tree once 

 infected is liable to show the disease more or less every year. No buds 

 should be taken from infected trees for budding nursery stock or in the 

 orchard. Since nearly all the affected leaves of peach trees fall away 

 before the time of the selection of buds, the trees should be carefully 

 selected in the months of May and June in order to avoid those which 

 have the disease. Where only a few branches of a tree are affected, 

 pruning a considerable distance below the affected portion might be 

 tried, especially in the case of those plum trees having the bud 

 deformation. 



The author gives a list of the species of Exoascus described as occur- 

 ring on species of Pninns in the United States with tlieir hosts: 



"Exoascus deformans, deforming the leaves and rarely the shoots of I'runusjiersica; 

 E.priini. deforming the fruit, causing 'bladders' or plum 'pockets' of F. domestica; 

 E. insititiw, causing 'witches brooms' and deforming the leaves of P. jiennsylcanica; 

 E. ccrasi,' csiusmg 'witches brooms' and deforming the same on P. avium; E. coufusus, 

 deforming the fruit and floral envelopes of P. virginiana; E. farlowii, deforming 

 the fruit and floral envelopes of P. seroUna; E. communis, deforming the fruits of 

 P. maritima, P. pumUa, P. americana, and P. nigra; E. longipes, deforming the fruit of 

 P. americana; E. mirahilis, deforming the leaf buds and twigs, forming 'pockets,' of 

 P. angustifolia, P. Iwrtulana, and P. americana; E. mirahilis tortilis, distorting the 

 fruit of P. angustifolia; E. rhizipes, deforming the fruit and leaf buds of P. trijlora; 

 E. decipiens, deforming the leaves and shoots of P. americana; E. decipiens superficialis, 

 deforming the surface of the fruit of P. americana; E. varius, deforming the leaves 

 and shoots of P. serotina and P. dcmissa {?); E. cecidomopMlns, affecting cecidomid 

 galls on the fruit of P. virginiana." 



Of this list the following are given as new species: Exoascus varius^ 

 E. mirahilis, E. mirahilis tortilis, E. lorH/i])es, E. decipiens, E. decipiens 

 superficialis, E. rliizipes, E. confiisus, and E. cecidomophilus. 



Journal of Mycology ( U. 8. Bept. Agr., Division of Vegetable Fatliol- 

 ogy, Journal of Mycology, vol. VII, No. 4, pp. 333-478, pis. 7). — Briefly 

 summarized, the contents of this number consist of the following: 



Treatment of pear-leaf blight in the orchard, M. B. Waite (pp. 333-338). — 

 Exi)eriments were conducted in an orchard containing about 16,000 

 trees, mostly Bartletts, near Scotland, Virginia, for the prevention of 

 pear-leaf blight {Entomosporium maculatum). In 1892 5 sprayings of 

 Bordeaux mixture were given about 100 trees, resulting in entirely 

 preventing the disease. The dates of application were April 28, May 

 15 and 30, and June 14 and 29. Owing to the satisfactory results 

 obtained in 1892, in 1893 the owners decided to spray the entire orchard. 



