DISEASES OP PLANTS. 647 



111(1 its morphologic;! 1 and hiolosioai characters, as shown in pure cultures in 

 various media, are descrilied at considerahle length. 



Inoculation experiment.s have heen made on a number of plants in .idditioii 

 to the potato, .and it was found to successfully inoculate the tomato, ground 

 cherry, peppers, and cucumher. t)nt failed to jiroduce .-my results, the wounds 

 (piickly healing on the eggplant, thorn aiiple. petunias, and a numl)er of other 

 plants more or less related to the potato. 



The disease seems to be quite jirevalent throughout Canada, and in 190." it 

 is estimated to have caused losses amounting to .$72(>,U()(i. 



Investigations show that undoubtedly the principal means of infection 

 comes from the diseased condition of the seed ])otato when jilanted. If the 

 organism is in the soil, infection apparently may be jiroduced through the 

 seed tuber, and infection may also be produced through wounds, as has lieen 

 repeatedly demonstrated. The moisture of the atmosphere and soil .-ire shown 

 to be conditions which influence the spread of the disease. 



It has been found that certain varieties of potatoes under field conditions are 

 more immune than others, and as methods of prevention the author suggests 

 tile planting of rot-resistant varieties, the use of seed potatoes that ai"e free 

 from disease, planting in well-drained land, reducing insect injury by the use 

 of Paris green or other insecticides, preventing the growth of fungi by the use 

 of I'.ordeaux mixture, and, finally, the rotation of crops. 



The heart rot of beets, Merle (La Maladie du Coeur de la Betterave. .JoUj)i}i: 

 Hawelin, 190(!; rer. in Prog. Agr. ct Vit. {Ed. VEst). 2K (1907), No. 1, pp. 20, 

 27). — An account is given of a disease of sugar beets which is attributed to 

 I'honia tahifica or P. beta-. 



This disease it is said usually makes its appearance in the field between the 

 middle of July and the end of August when here and there may be seen leaves 

 which present a wilted appearance, as is frequently observed on a very hot 

 day. The next morning the leaves instead of having a refreshed appearance 

 are still wilted, and if examined the petioles will be found to be brown spotted, 

 and the leaves finally die. Later the disease becomes (juite evident on the root, 

 ultimately causing its destruction. 



The disease seems most frequent on sandy day soils, and for combating it 

 deep culture, particularly during the fall and winter, the apjilication of wood 

 ashes, long i)eriods of rotation, and the i)laiiting of i-esist;iiit varieties are 

 recommended. 



Sclerotinia libertiana as the cause of the rotting of root crops, O. Appei. 

 and W. F. Bruck (Arb. K. Biol. An.st. Lmid ii. Forstir.. .', {I'iOG), No. J,, pp. 189- 

 203, figs. 7). — An account of the rotting of various root crops in cellars and 

 storage jiits, the injury being attributed to the presence of the fungus Sclerotinia 

 libcriiaiia. Descriptive notes are given on the fungus and :i report made on the 

 investigations regarding its host plants and methods for preventing its occur- 

 rence ;ind spread in stor.-ige. 



A grass-destroying myxomycete, T. Wulkf (Zt.'^lir. I'/ltnizciihnnil.-.. I(> 

 {190(1), A'o. .'/, pp. 202-200, pi. 1). — An account is given of severe injury to 

 various species of grasses by Physarnm cincrcimi. 



The clover broom rape, E. Makke (Prog. Agr. ct Mt. {Ed. rE><t). 27 {191)1!). 

 \o. .'i9, pp. ()S]-(19(), figs. 7). — Descriptions are given of Orobancltc niinnr. an 

 active parasite of clover, and attention is called to the necessity for careful 

 cleaning of seed and the use of manures and fertilizers to prevent the spread 

 of the parasite. 



Eelworms, W. E. Collinoe (Vniv. Birmingham, Dept. Econ. Zool. Cin. 1. pp. 

 -'/>. — P.rief accounts of the root knot eelworm { Hcierodera radirirola ) . wliich is 

 exceedingly common and injurious to tomatoes, cucumbers, and other garden 



