DISEASES OF PLANTS. 1083 



known as occurring in France for a considerable time, \\ here it hag assumed the pro- 

 portions of a destructive epidemic. It has been recently reported in several widely 

 separated localities in England, on \\ hich accounl attention is drawn to it. 



The symptoms of the disease are said to be very marked and can nol be con- 

 founded with those of any other tomato disease at present known. When the 

 tomato is about the size of a marble a minute black patch appears at the base. of the 

 style. This patch gradually increases in size, retaining a circular outline, until 

 eventually the entire fruil is reduced to a blackish, soft, decayed mass. 



Experiments have shown thai infection takes place during the flowering stage and 

 that the bacteria causing the disease are deposited on the stigma by Mies visiting the 

 flowers. 



The stigma seems to be the only vulnerable part under ordinary conditions, bul it' 

 bacteria from adiseased fruit are introduced into the flesh of a healthy tomato, infec- 

 tion follows. 



The disease does not appear to be influenced to any extent by the forcing methods 

 commonly followed, as it has been observed in houses where the temperature was 

 kept comparatively 1<>\v. 



When the disease appears all diseased fruit should be removed as quickly a- pos- 

 sible, and insects should be excluded by using insecticides. Where this is done, 

 artificial pollination will be necessary. 



The blight canker of apple trees, II. II. Whetzel [New York Cornell Sta. Bul. 

 236, pp. 101-138, figs. 36). — A description Is given of a form of apple-tree canker 

 which is due to the same cause as thai which produces the bacterial orfireblighl of 

 the pear. It seems to be favored by rapid growth of the trees, and the points of 

 inoculation are water sprouts, wounds, and possibly the flowers. After reviewing 

 the different kinds of cankers that have been described as occurring on apple trees, 

 the author gives the distinguising characters and appearance of the canker treated in 

 this bulletin, which is due to Bacillus amylovorus. 



These cankers occur most frequently on the bodies and limbs of young tree-, and the 

 diseased areas are sunken and smooth, covered with a brown surface, but not show- 

 ing any pimples or fungus fruit bodies, which characterize some of the other forms 

 of fruit-tree canker. The effect of the disease on the tree is to lower its vitality by 

 cutting off the food supply to the roots and indirectly reducing the flow of sap to 

 the branches and leaves. "" 



Inoculation experiments have shown that the disease can be readily caused through 

 wounds. As preventive measures the author recommends the burning of all dead 

 limbs and trees as promptly as possible and cutting out and burning every trace of 

 twig blight on both apple and pear trees as soon as detected. When pruning, all 

 cut surfaces should be treated with corrosive sublimate or copper sulphate solution. 

 Water sprouts should be cleaned from the tree-, and the excessive use of nitrogenous 

 fertilizers should be avoided. When possible the planting of varieties known to he 

 resistant to the disease is recommended. Wolf River and Talman Sweet appear to 

 be quite resistant, while Baldwin and Ben Davis suffer severely. In order to prevent 

 the spread of the disease the author suggests an early spring treatment with lime- 

 sulphur wash. 



Notes are given on the distribution and severity of the disease throughout New 

 York, and a detailed account is L. r i\en of the identity of the organism, and notes on 

 its morphology, cultural relation, etc. A bibliography of the publications relating 

 to this disease completes the bulletin. 



A fungus disease of the mandarin orange, P. A. Saccabdo {SeparaU from Ann. 

 My col., pp.3; abs.in Zlschr. Pflanzenkrank., 15 (1905), No.3, p. 175). — The author states 

 that mandarin oranges were noticed in Naples that showed dark spot- on the rind, 

 the spots later becoming confluent. 



33747— No. 11—06 5 



