DISEASES OF PLANTS. 351 



193-219, figs. 28). — Compiled accounts are given of the various fungus and 

 other diseases to which the coffee plant is subject, 18 species of fungi and 1 

 alga being described as parasitic on the leaves, stems, roots, and fruits of the 

 coffee plant. In addition several phenogamous plants are listed that occur as 

 parasites or semiparasites. Notes are also given on the injui-y done by nema- 

 todes, snails, mites, insects, etc. 



The coconut stem disease, T. Fetch (Trop. Agr. and Mag. Ceylon Agr. fe'oc.. 

 33 {1909), No. 1, PI). 13-15).— On account of the possibility of the distribution of 

 the spores of Thielaviopsis cthaceticns, the cause of the coconut stem disease, 

 by water, coconut husks, and other means, the author has carried on some 

 experiments to test the vitality of the spores and the possible means of dis- 

 tribution. 



The spores were found to grow only in solutions containing sugar, and on 

 this account the fungus is found only in the portions of the stem containing 

 sugar in some form. The sjiores retained their germinative capacity for a con- 

 siderable time, particularly if kept dry, and experiments shpwed that they 

 were quite resistant to many chemicals. 



The author believes that the disease is not as destructive or as rapidly dis- 

 seminated as formerly stated, although it apparently causes considerable loss. 



Som.e studies of nonparasitic plant diseases, P. Graebner (Ztschr. Forst u. 

 Jagdw., Jfl {1909), No. 7, pp. .'f21-.'f31, figs. 5). — Descriptions are given of the 

 effect of frost during the growing period on the oak, beech, hemlock, and fir. 



Gas injury to street trees, R. Hoerning {Gartenwcit, 13 {1909), No. Jf6, 

 pp. 5.ifo, o.'fO). — An account is given of the injury in Kiel to linden, locust, and 

 elm trees by illuminating gas. 



A new Exobasidiuin disease on azaleas, R. Laxjbert {Handelsbl. Deut. 

 Gartenban, 2>t {1909), pp. .'iG6-Jf68; ahs. in Bot. Ztg., 2. Abt., 61 {1909), No. 

 20-21, p. 285). — In 1908 in some of the Rhenish provinces a disease of culti- 

 vated azaleas appeared which the author has studied and found to be due to 

 Exohasi'iiinn sp., a form apparently related to E. discoideum and E. ledi. The 

 fungus seems to be able to attack species of A'accinium, Rhododendron, and 

 Azalea, producing similar characteristics, and for its control it is recommended 

 that the diseased parts be cut out and the plants treated with Bordeaux mixture 

 or sulphur. 



The diseases of euonymus, E. Foex {Prog. Agr. et Vit. {Ed. VEst-Centre), 

 30 {1909), Ao. J,6, pp. 614, 615).— The author calls attention to the fact that 

 under the term euonymus disease 2 diseases are confused, one caused by the 

 scale insect Diaspis cuonymi, the other due to the conidial phase of a mildew. 

 For the control of the former the use of insecticides is advised, while for the 

 fungus the application of solutions of permanganate of potash, carbonate of cop- 

 per, or Bordeaux mixture is recommended. 



A remedy for the mildew of euonymus, P. Jany {Prog. Agr. et Vit. {Ed. 

 VEst-Centre), 30 {1909), No. ^3, pp. .',99, 500).— For the control of the powdery 

 mildew of euonymus the author recommends dusting the shrubs with sulphur 

 when the active growth is just beginning. One application has proved success- 

 ful for several years in controlling this disease. 



A nematode disease of chrysanthemums, E. Molz {Centhl. Bald, [etc.], 2. 

 Alit.. 23 (1909). \o. 21-25, ;>p. 656-611, pi. 1, figs. 2).— The author describes a 

 disease of chrysantliemums due to the nematode A iihelenchus olesistus. The 

 nematodes infest the above-ground part of the plants, causing considerable 

 injury. 



Investigations have shown that chemical treatments that are sufficiently 

 strong to destroy the nematodes also injure the plants. The best means of com- 

 bating this pest is believed to be through the sterilization of the soil with 



