662 JOUENAL OF THE EOYAL HORTICULTURAL SOCIETY. 



of a ferment, and pass between, or occasionally across, the cells of the 

 host plant. Infection generally takes place near the edges of the 

 leaves. 



The disease is of little practical importance, and in a warm, dry 

 summer would probably not show itself. A table is given showing 

 the characteristics of different bacteria pathogenic to the potato. 



A. D. C. 



Potatos and other Crop Plants in Nevada, The Nematode 

 Gall-Worm on. By 0. S. Scofield {U.S.A. Dep. Ayr., Bur. PI. Ind., 

 Circ. 91 ; Feb. 1912 ; 21 figs.). — The gall-worm occurs very generally 

 in the Southern United States. In many places it is found in such 

 large numbers as to be a serious pest to many plants, such as the peach, 

 fig, cotton, cow-peas, and many vegetables. In seed potatos they 

 are particularly dangerous, as the land planted with them will be 

 infected with the worm. Infected potatos do not always show the same 

 symptoms, but usually the skin is roughened and broken in patches 

 and there is a ring of darkened tissue just under the skin, a micro- 

 scopical examination of which will reveal the presence of the mature 

 females and young larvae. The presence of the worm causes swellings 

 or galls on the roots of infested plants. 



Probably the best means of combating the nematode is by planting 

 crops which are known to be free from its attacks. Corn, wheat, rye, 

 barley, and oats are among the plants not subject to its attentions. All 

 nursery stock should be carefully inspected prior to planting, and 

 potatos should not be used for seed if they come from an infected area. 

 With regard to indoor crops, the soil used in greenhouses and frames 

 can be sterilized. — V. G. J. 



Potato Tubers, On the Cause of Blindness in. By Elizabeth 



Dale (Ann. Bot. xxiv. pp. 129-131; 1912). — The author describes a 

 blindness of potato tubers caused by the fungus Verticillium alho- 

 atrum. She summarizes her results as follows. The mycelium is 

 present in the blind tubers, where it causes the destruction of most of 

 the eyes. It grows up into the new shoots when any are formed, 

 and in some cases it may pass into the sub-aerial shoots. In other 

 cases it never goes beyond the subterranean; stems, and creeps along them 

 into the newly formed tubers, internally as a colourless mycelium in 

 the cortical tissues, externally as a scanty, thin, brown mycelium. 

 Thus the tubers may be infected by means of the vegetative myceHum 

 only, without the formation of any kind of spore. The course of the 

 fungus from the old to the new tuber may be traced by means of 

 the brown coloration of the aerial tissues. Tubers have been grown 

 in three successive years from the original diseased crop, and in each 

 year some have been blind. — A. D. G. 



Potato, Variations of the {Bev. Hort. d'Alg. p. 422; Dec. 

 1912). — As the result of experiments and investigations, the writer 

 asserts that as far as the wild races of Solanum are concerned 

 {S. Commersonii, Maglia, utile, verrucosum, edinense) their essential 



