DISEASES OF PLANTS. 5(^5 



examined as to purity, and tlie character and extent of impurities in the different 

 sanijiles are shown in tabular form, and a discussion is given of the results shown 

 in the tables. In general, it ai)peared that low i)riced seed always contained a 

 greater amount of imi)urities than were found in good seed, although a high price 

 did not necessarily mean that pure seed was supplied the purchaser. In the case of 

 timothy seed, only 9 out of 85 samples fell below 98 per cent purity; while of the 

 led clover, out of 74 samples examined, only 29 were up to the standard of 98 per 

 cent of purity. 



Killingweedswith chemicals, L. R. Jones ( Vermont Sta. Rpt. 1900, pp.SS2-2S6). — 

 The value of salt applied l)r()adcast for the destruction of the orange hawkweed, as 

 shown by a previous investigation (E. S. R., 8, p. 987) is stated. Sulphuric acid, 

 diluted to 1 jmrt of acid in 40 of water, has been claimed as more efficient than salt 

 for the destruction of this weed. The author repeated his experiments with salt, 

 making comparisons with a dilute sulphuric acid. The results obtained indicate 

 that sulphuric acid is not to be compared with salt as a remedy for the hawkweed, 

 and the author states his belief that salt is the best chemical yet tried for killing the 

 orange hawkweed. 



Experiments were conducted with copper sulphate solution for killing charlock, 

 or "kale " as it is known in the State. In addition to the charlock 3 other species 

 of Brassica are known as kale, but these have a smooth, glaucoiis foliage and are 

 but little injured by chemicals. Sprayings were made in oat fields in which 3 and 

 5 per cent solutions of copper were applied. The first application was given when 

 the plants were quite small. During the following night heav)^ showers fell which 

 (loul)tleifis influenced the results. This application resulted in the injury or destruc- 

 tion of fully f of the plants, about \ seeming to be uninjured. About a week later 

 other plats were sprayed, no rain falling for several days. In this case nearly 70 

 jier cent of the plants were killed outright and others injured. Practically every 

 plant of charlock was killed by the last spraying and most of those by the earlier 

 one. The oat plants were slightly injured but soon recovered. The use of copper 

 suli)hate at the rate of 1 IV). to 4 gal. of water when sprayed upon young plants is 

 said to be efficient for their destruction, but the author believes that the best way to 

 deal with these weeds, where it is possible, is not by the use of chemicals but by 

 frequent rotation and clean cultivation. 



DISEASES OF PLANTS. 



Phytopathology and its service to agriculture, E. Marchal {Jour. Soc. Cent. 

 Ayr. Bf'l;/., ^s" {1901), No. 7, pp. 24^^-247). — A brief resume is given of the present 

 status of f)ur knowledge relating to j)lant diseases and the means of combating them. 



Notes on plant diseases, E. M. Wilcox [OklaJioma St((. Kjit. 1901, p]>. 116-128, 

 ]/ls. 2). — Descriptions are given of tlie apple-leaf rust, and rusts and smuts of cereals. 

 The author describes the hot-water treatment for the stinking smut of wheat and 

 oats and the loose smut of wheat and barley, and recommends its more extended 

 use. The corn and sorghum smuts are described at some length and references given 

 to literature relating to the smuts and rusts of cereals in general. 



Notes on some species of Helminthosporium, and the diseases of barley 

 and oats occasioned by them, F. K. Kavx [Zlsrlir. J'flanzcnkrdid-., 11 {1901), No. 

 1, pjp. 1-26, ph. 2, figs. 8). — Studies are given on the morphologj^ and physiology of 

 Ilelininthot'porium gramineum, H. trrcn, and //. avense. These fungi are parasitic, the 

 first 2 on barley and the last on oats. The author, following Rostrup, refers to these 

 diseases as the striped diseases of barley and oats, the name being derived from long 

 discolored stripes occurring on the leaves, leaf sheaths, stems, etc. Prillieux has 

 given the name Ilelminthosporiosis to these same diseases. Inoculation experiments 



