252 FUNGOID PESTS OF CULTIVATED PLANTS. 



FLAX RUST. 

 Melampsora Lini (DC.), PL XXIV. fig. 32. 



This is a destructive pest to cultivated Flax, and is very common on 

 the little wild species of purging Flax. 



The pustules of the uredo are small, rounded, and scattered, of a bright 

 orange colour on the leaves, stems, and sometimes on the flower buds. 

 Uredospores almost spherical, or egg-shaped (15-24 x 14-1 8/u), orange- 

 yellow, and externally rough. 



The pustules of the teleutospores form rather large blackish patches 

 on the stems, quite smooth and shining. The teleutospores are wedge- 

 shaped, and closely packed side by side, covered by the epidermis (45-60 

 x 17-20 //). They act very effectively, as resting spores, to carry the pest 

 through the winter and provide for the reappearance of the uredo in the 

 spring. 



It has been observed in France, Germany, Belgium, Holland, Switzer- 

 land, Finland, Russia, Dalmatia, Austria-Hungary, Bohemia, Italy, Siberia, 

 and in South Africa, Australia, and North America. 



Burning the stems, or any portions which exhibit the patches of 

 teleutospores, should be insisted upon, if the disease is to be kept in 

 check. 



Sacc. Syll. vii. 2107 ; Mass. PL Dis. p. 238 ; Cooke, M-. F. figs. 165- 

 167 ; Cooke, Hdbk. No. 1596. 



HEMP LEAF-SPOT. 

 Phyllosticta Cannabis (Kirch.), PI. XXIV. fig. 31. 



On the living and languishing leaves of the Hemp plant. Spots on 

 the upper surface, somewhat circular, tawny, becoming paler ; perithecia 

 punctiform and scattered ; sporules hyaline, elliptical, straight or curved, 

 very minute, with one or two guttules (4-6 x 2-2^/x,), hyaline. 



Has occurred in Northern Italy and Bohemia. 



Sacc. Syll. iii. 294. 



FUNGICIDES 



are mixtures which are applied to diseased plants either to prevent or 

 mitigate the ravages of fungoid parasites if in a fluid form by sprinkling, 

 spraying, or sponging the foliage ; and if in powder by dusting it over the 

 plants or the soil, as the case may require. See also JOURN. R.H.S. xxix. 

 1905, p. 900. 



FLUID. 



Ammoniacal Carbonate of Copper. Mix three ounces of sulphate of 

 copper and three ounces of carbonate of soda with one quart of concentrated 

 ammonia, and as soon as all action ceases dilute with twenty-two gallons 

 of water. Some persons advocate the dilution with twenty-eight gallons 

 of water as being less injurious when applied to fruit. 



May be used in greenhouses, and is especially useful in epiphytic 



