1917] DISEASES OF PLANTS. 47 



features in connection with the enforcement of the destructive insect and pest 

 act, investigations in plant pathologj', economic botany, and a report of the St. 

 Catharines field laboratory. The work reported in the administration of the 

 destructive Insect and pest act has consisted largely of inspection of potatoes 

 for shipment. 



In plant pathology, the diseases reported upon are principally those of po- 

 tatoes, a number of which are described, and the results of experiments are 

 given in some cases. Experiments on the effect of fresh manure on potato scab 

 show that fresh horse manure increased the amount of scab more than any of 

 the others used, while the use of sheep and hen manure resulted in the smallest 

 amount of scab. A potato disease called net necrosis is briefly described. This 

 is characterized by brownish di.scolorations of the fibrovascular bundles of the 

 tubers. Some experiments were undertaken to determine whether tubers that 

 showed this infection before planting would produce a crop free from the dis- 

 ease, and the results indicate that in almost every case the disease is hereditary. 

 Some investigations on the control of Ithizoctonia or black scurf of potato, 

 due to Corticium vagnm solani, are reported in which it appears that treating 

 seed tubers for three hours with a solution of corrosive sublimate in connection 

 with rotation of crops has greatly reduced loss from this disease. Notes are 

 given on the distribution and characteristics of black leg, leaf roll, and mosaic 

 disease of potato. A clover and alfalfa wilt disease due to Sclerotinia ciborio- 

 ides, or S. trifoliorum, is briefly described, and two authentic cases of its occur- 

 rence in Canada are reported. 



In the investigations in economic botany, most of the work has been con- 

 cerned with the identification of poisonous plants and weeds. 



In the report from the field laboratory at St. Catherines, W. A. McCubbin 

 gives observations and experimental results on the more important diseases of 

 fruits and vegetables observed during 1914. Most of the investigations are 

 said to be incomplete and are only briefly described. 



Notes on plant diseases of Connecticut, G. P. Clinton {Connecticut State 

 Sta. Rpt. 1915, pt. 6, pp. .'(21-4-51, P's. 8). — Notes are given on a number of plant 

 diseases observed during 1914 and 1915, including some previously reported 

 and a number of others not before recorded from the State. Among the latter 

 are white spot of alfalfa; several rots of apples; white tip of carnations; mosaic 

 or white pickle of cucumber ; leaf blight, crown gall, and a root rot of mangels ; 

 anthracnose of Norway maple ; a Fusarium rot of onions ; two rusts of poplar, 

 one of which is associated with the larch, the other with hemlock ; crown gall 

 of privet ; and a bacterial leaf spot of soy beans, which is provisionally de- 

 scribed as due to BaciUiis sp. 



Report on plant protection, E. Schaffnit and G. Lxjstner {Berichte iiber 

 Pflanzenschutz der PflanzenschutzsteUen. Bonn: P.Rost & Co., 1916, pp. 98, figs. 

 11). — This contains the reports of the stations for plant protection at Bonn- 

 Poppelsdorf and Geisenheim for 1913-14 regarding weather and plant injury 

 as related to diseases and animal pests. 



Administration report of the government mycologist for 1914—15, W. 

 McRae {Rpt. Dept. Agr. Madras, 1914-15, pp. 50, 51). — It is stated that a con- 

 form bacillus isolated from the soft rotting parts of coconut and palmyra palms 

 attacked by bud rot did not reproduce the rot when injected into the buds of 

 young coconut palms. The results of inoculations of these plants with pure 

 cultures of Pythiuin palmivorum confirmed the experiments of the previous year. 

 Bud rot of coconut palms appears to be widely spread in Malabar, but the 

 damage done is not extensive. Investigation of a new disease of coconut palms 

 on the west coast has been begun. 



