DISEASES OF PLANTS. 245 



The relation of fertilizers, temperature, and humidity to tlie disease are 

 discussed and descriptions are given of nematode attacks, tomato spot, a disease 

 called hlack stripe, and white fly injury. 



Regarding the relation of fungus attack upon the foliage of trees to 

 disturbances in roots and lower trunk, II. Farneti {Riv. Patol. Veg., 6 {191S), 

 No. 4-5, pp. 97-107). — Discussing numerous examples cited, the author claims 

 that functional disturbances, debility, and bad constitutional conditions gener- 

 ally do not necessarily predispose trees to fungus attack. 



Diseases of the orchard, L. Caesar (Ann. Rpt. Fruit Growers' Assoc. Ontario, 

 4Jf {1912), pp. 22-25, figs. //). — Notes are given on black rot canker, apple scab, 

 and pear blight, with suggestions for their control. 



The transpiration of apple leaves infected with Gymnosporangiuni, H. S. 

 Reed and J. S. Cooley (Bot. Gaz., 55 {1913), No. 6, pp. 421-4^0, fig. i).— Sub- 

 stantially noted from another source (E. S. R., 29, p. 647). 



The apple rust {Rpt. W. Va. Dept. Agr., 1913, No. 29, pp. 20-24, fig. l).—ln a 

 paper presented before the twentieth annual meeting of the State Hoi'ticul- 

 tural Society attention is called to the rust of apples and its related form on 

 cedars, with the object of reducing the occurrence of the disease as much as 

 possible by the removal of cedar trees in the vicinity of orchards. It is stated 

 that the disease can be controlled by proper spraying, but as the period when 

 the application of the fungicide should be made is quite limited a more practi- 

 cal method of control is believed to be the elimination of the cedar trees. 



The collar blight of apple trees, N. J. Giddings {Rpt. W. Va. Dept. Agr., 

 1915, No. 29, pp. 15-19, fig. 1). — In a paper presented before the twentieth 

 annual meeting of the State Horticultural Society, the author states that three 

 troubles of apple trees, collar blight, winter injury, and root rot, are frequently 

 met with and often confused. 



The collar blight disease, it is said, may be detected in its early stages by 

 a close inspection of each individual tree. The affected trees usually show 

 a discolored area of bark just above the ground, and the bark is frequently 

 sunken. By cutting into the bark it is found to be dead and black, and a 

 reddish discoloration is observed where the wood and bark come together. At 

 later stages in the progress of the disease the dead bark often becomes broken 

 up and rot fungi easily gain access. An examination was made of a number 

 of orchards, and a considerable proportion of trees of bearing age was found 

 effected. 



The only remedy at present known is that of cutting out and treating the dis- 

 eased areas. Differences are noted in the susceptibility of varieties of this trou- 

 ble, and it has been suggested that double working nursery stock has given 

 relief. 



A bacterial canker of plum twigs, I. M. Lewis {Trans. Amer. Micros. Soc, 

 31 {1912), No. 3, pp. 145-149, pi. 1). — The author states that a disease of plum 

 trees, popularly known as canker, is quite prevalent in portions of Texas and 

 Is apparently identical with that which has been reported from Nebraska and 

 Delaware (E. S. R., 18, p. 244; 19, p. 445). Small cankers are observed on the 

 wood of the first season's growth, and these enlarge until finally the twigs may 

 become completely girdled. 



A bacterium {Pseudomonas priini) has been isolated and cultivated, and 

 inoculation shows that it is responsible for the trouble. In addition it was 

 found possible to produce typical cankers on young peach trees with the organ- 

 ism taken from the plum. 



Physiopathological observations on the stigma of the olive flower, L. 

 Petri {Mem. R. Staz. Patol. Veg. Roma, 4 {1913), pp. 139-160, figs. 7; a&s. in 



