DISEASES OF PLANTS. 253 



or alfalfa fields not capable of irrigation, it is reeonnnendcd that tli(! infested spots 

 be cnt, artificially watered, and then treated with the nitrate of soda in the same 

 maimer as recommended above. 



The water hyacinth {Qacenddnd Agr. Jour., S [I'JOl), No. 5, pp. 368, 369). — 

 Notes are iriven npon the rapid spread of the water hyacinth in some of the rivers of 

 Australia. 



Eradication of charlock by spraying, \\. Somervillk {Tran.^. HUjhland and 

 Agr. Sor. Scotland, S.ser., 13 {1901), pp. 10-17). — A popular account is given of the 

 occurrence of charlock, the nature of injury produced by it upon various crops, and 

 a review given of the experiments which have been conducted for its eradication })y 

 spraying with solutions of copper and iron sulphate. The results obtained are briefly 

 summarized and suggestions given for the preparation of the herbicides, the proper 

 time for spraying, form of spraying machines, etc. 



Spraying for the destruction of mustard, J. Fletcher {Canada Expt. Farms 

 Rjjts. 1900, pp. 248, 24-9) . — Experiments were conducted under the author's direction, 

 in which the efficiency of spraying wild mustard with solutions of copper sulphate 

 was tested. The results were in the main satisfactory, although the experiments 

 were carried out rather late in the season. In general, it seems that, when young, 

 charlock may be destroyed with a 2 per cent solution of copper sulphate at the rate 

 of 40 gal. per acre, but if the i)lants are in flower as much as 60 gal. of a 4 per cent 

 solution will be required. 



Investigations on the effect of various salt solutions upon weeds and 

 cultivated plants, B. Steglich {Zfsdir. Pfanzenkmnk., 11 {1901), Xo. 1, pp. 31-83). — 

 A report is given of a number of experiments on the effect of a 20 per cent solution of 

 iron sulphate, 15 and 30 per cent solutions of sodium nitrate, ammonium sulphate, 

 potassium chlorid, and magnesium chlorid, when sprayed over cultivated plants and 

 weeds. Cereals were not permanently injured by any of the solutions, and beets 

 were only seriously affected by the iron sulphate solution. Potatoes were either 

 seriously injured or killed by all of them, and serious injury followed the use of the 

 stronger solutions upon beans, peas, vetches, yomig clover, lupines, and flax, and 

 slight injury was observed on old clover plants. The only weeds that were killed 

 by all of the different solutions were wild radish and charlock. Thistles were 

 injured by the stronger solutions. The sow thistle was seriously affected by the 

 stronger solutions of ammonium sulphate and potassium chlorid, and the same solu- 

 tions were proved injurious to some extent upon species of Rumex. Knotweed 

 {Polygonum persicaria) was killed by the 30 per cent solutions of sodium nitrate and 

 calcium chlorid, while other species of knotweeds were not affected by the chemicals. 



Weed-killing compounds, F. T. Shutt {Canada Expt. Farms Rpts. 1900, p. 187). — 

 A report is given of an analysis of Harvesta, a chemical compound which is sold for 

 the purpose of destroying weeds in gravel paths. The analysis showed the com- 

 pound to consist of arsenite of soda and connnon salt. Formulas are given for the 

 preparation of a number of other weed-killing compounds. As all these chemicals 

 seriously injure soils intended for cultivation, they should be used only where cul- 

 ture is not contemplated. 



DISEASES OF PLANTS. 



Report of the mycologist, F. I). C^uestek {Delaware >Sta. Rpt. 1900, pp. 36-46, figs. 

 7).— In continuation of the report of the previous year (E. S. R., 12, p. 761), the work 

 carried on for the treatment of api>le scab is reviewed and a sununary given of the 

 results obtained the fifth consecaitive year. During the season covered by this report 

 both treated and untreated trees yielded good crops. The Winesap trees showed 

 little difference to be attributed to the spraying. In the case of the Strawberry 



