DISEASES OF PLANTS. 359 



The weedy plants of Iowa, L. H. Pammkl [Proc. Sar. Prom. Aijr. Sri, 1900, pp. 

 173-177). — Notes are given on the geographic ilistril)ution of a nunil)er of weeds 

 throughout the State, and attention called to the very slow distribution of some spe- 

 cies as ('onipan>(l with the rajjid s]ire-ad of others. 



The use of chemical substances for the destruction of weeds among grow- 

 ing cereals, C. Dusserre {Chroit. A//r. Qinlon VhikJ, 14 (1901), Xo. 9, jip- 253-256, 

 fig. 1). — The author comments upon the use of solutions of copper sulphate, iron sul- 

 phate, and sodium nitrate for the destruction of wild mustard, charlock, and wild 

 radishes, and claims that experiments show that the quantity of liquid employed 

 should be greater than that generally recommended. Where 2 to 5 per cent solu- 

 tions of copper sulphate, or 10 to 20 per cent sodium nitrate, are employed, the amount 

 of licjuid, the author claims, should be from 800 to 1,000 liters per hectare, a quantity 

 more tlian double that usually recommended. For the application of the herbicide 

 the author i-erommends power sprayers, and one which has proved very efficient is 

 figured and described. 



A new raethod of cleaning roads and walks {Gard. Chron., 3. ser., 29 {1901), 

 No. 753, p. 358). — A brief note is given on a machine for the destruction of weeds in 

 drives and walks in which the direct heat of burniiig fuel is l)rought to bear on the 

 surface of the walk, charring and killing all weeds, grasses, and fallen seeds. The 

 machine consists mainly of an inclosed fire box for holding coke in a state of com- 

 bustion and a drum containing a fan for creating a draft. The machine may be 

 drawn about the grounds, allowing it to stand still for a few seconds. It is said to 

 be very efficient, and to do away with the expensive work of hoeing drives, paths, 

 etc., or th3 use of arsenical poisons, hot water, salt, etc. 



DISEASES OF PLANTS. 



Twenty years' progress in plant pathology, B. T. Galloway {Proc. Soc. Prom. 

 Agr.Sci., 1900, pp. 90-102). — While the subject of plant pathology has had its stu- 

 dents for a century, the real development of the subject has taken place in the last 

 20 years. The author reviews the work of some of the pioneers on the subject, and 

 devotes special attention to the organization and development of the study of plant 

 pathology in this country. The progress is said to have been made in two distinct 

 epochs; the first was concerned with the development of fungicides and means for 

 their application for the prevention of diseases, while the second is represented by 

 more careful research work into the life histories of the fungi and study of the normal 

 and pathological conditions of the plants. 



Flax wilt, H. L. Bolley {North Dakota Sta. Rpt. 1900, pp. 4o-48). — A prehminary 

 report is given of observations made upon a disease of flax, which for want of a better 

 name the author has designated as "flax wilt." Little attention seems to have been 

 paid to this disease in this country, although it appears to have been observed in 

 Europe. It has been repeatedly observed that after flax has grown for a number 

 of years upon the same land, the crop becomes very much lessened in yield. This 

 has been attributed to impoverishment of land, but soil analyses show that this can 

 not be the fact. The investigations of the author indicate that the disease is due to 

 a parasitic fungus which lives in the soil and in the old decaying flax stubble. It 

 may be transmitted to a new field by the transfer of dirt from an infected one, or by 

 infusions made from diseased jjlants. Investigations made in a number of fields seem 

 to indicate that the disease may be communicated through seed flax. The fungus 

 appears to attack the roots of the i)lants most strongly at a depth of soil correspond- 

 ing to the l)ottom of the furrow. An examination shows that the parasite fills the 

 vessels and tissues of the roots with its filaments, cutting off the water supply and 

 bringing about a typical wilt. A number of experiments have been inaugurated, 



