May, 1920J PATHOLOGY 231 



1625. Bakss, H. P. Prune troubles of non-parasitic nature. Better Fruit 13': 7 

 24-20. 1919. Address delivered before Oregon State Eorticultural Society, Flo eburg Dec 

 7, 191 S. MiTects of the extraordinary climatic conditions in Western Oregon in L018upon the 



fruit of plums (prunes) is considered in :i popular way. The following nonparasitic diseases 

 or physiological disturbances arc discussed at length: CI) "Gum spot" or formation of spots 

 of a gummy substance either wit li in or mi the outside of green fruits. Affected fruit becomes 

 irregular in shape and finally turns dark. Differences between the demand and supply of water 

 during the critical time of the growing season is thought to be the cause of this disturbance. 

 (2) Internal browning, another non-parasitic disease, is briefly considered. Sudden supply 

 of moisture after a prolonged drought is mentioned as a possible cause. Conservation of the 

 moisture Supply in soil during the time of greatest demand of the tree is suggested as the 

 most feasible remedy of the above non-parasitic diseases. — A. E. Murneek. 



1626. Boyd, J. Nectria cinnabarina as a parasite. Quart. Jour. Forest. 13: 139. 1919. — 

 In pruning young sycamores and elms in a plantation, every wound on all trees, with the 

 exception of those on a few acres, was coated with coal tar. On the small section referred 

 to, the wounds were treated with oil paint. In no single instance, was there an attack by 

 Nectria on a tree which had tar applied to the wound. Where paint was used, 90 per cent 

 of the trees were affected and about 20 per cent killed. — C. R. Tillotson. 



1627. Busgen, M. Biologische Studien mit Botrytis cinerea. [Biological studies with 

 Botrytis cinerea.] Flora 111-112:606-620. 1918. — In spite of numerous investigations on 

 Botrytis cinerea since the time of deBary, many points regarding it are still much in need of 

 light, especially the species question, the pathological relation of the fungus to a greater 

 number of plants and the enzymes which it produces. The contributions in this article are 

 to the last two problems. In an attempt to answer the question why so many plants grow- 

 ing under condition especially favorable to the development of B. cinerea, are not attacked 

 by it, the author inoculated many species of plants. The strain used was isolated from the 

 petals of Pelargonium zonale. The fungus was carefully studied in pure culture on a variety 

 of media and the conditions under which sclerotia and appressoria are developed are briefly 

 set forth. Since Beauverie obtained apothecia from Botrytis sclerotia, author hopes to 

 obtain them from his fungus. — For inoculation work bits of agar containing growing myce- 

 lium served as inoculum. The leaves of the plants only were inoculated both above and below 

 on each side of the midrib. The tissues on one side of the vein were injured by cutting. 

 Infection took on the wounded side without exception on all the plants. The types of lesions 

 produced are described for different hosts and the rate of spread of the mycelium in the tis- 

 sues was compared in many of them. These variations in character and rate of develop- 

 ment of the lesions resulting from wound infections are attributed to water content, chemi- 

 cal nature and aeration of the leaf tissues. — The action of the fungus on the chloroplastids, 

 nucleus, middle lamella, cell wall, cuticle, etc., is described for a large number of hosts in- 

 fected through wounds. — Of the 171 plants inoculated without wounding, 84 did not become 

 infected. The factors conditioning penetration through the uninjured epidermis are dis- 

 cussed. — H. H. Whetzel. 



1628. Captjs, J. Sur les invasions du mildiou dans le sudouest en 1916. [On the inva- 

 sions of downy mildew in 1916.] Ann. Serv. fipiph. 5: 193-200. 1918. — Correlation of telluric 

 conditions existing iii southeastern France with appearance and spread of Plasmopara viti- 

 cola in the vinej-ards. It is concluded that humidity rather than temperature is the factor 

 of importance in the progress of the disease. — D. Reddick. 



1629. Davey, H. W. Diseases of fruit trees and their treatment. Jour. Dept. Agric. 

 Victoria 16: 101-107. 1918. — Contains directions for treatment of the following diseases: 

 black spot of apple and pear, shot-hole of stone fruits, peach leaf curl, Armillaria root rot, 

 collar rot and chlorosis in citrus trees.— D. Reddick. 



