292 PATHOLOGY [BoT. Absts., Vol. X, 



mental evidence on which he bases his conclusion that the most effective control of this dis- 

 ease is obtained by cutting away the leaves of the plant on the first appearance of the fungus 

 and, later, as new leaves appear, by spraying 2 or 3 times during the season with Bordeaux 

 mixture. — H. H. Whetzel. 



1901. Slogtbren, E. van. De nematoden-bestrijding in de bloemboUenstreek. [Nema- 

 tode control in the bulb district.] Tijdschr. Plantenz. 26: 118-138, 161-171, 177-188. PI. 6, 

 7, and 11, fig. 1-3. 1920. — The nematode (Tylenchus devaslatrix) disease of narcissus presents 

 3 types of effects, corresponding to period of infestation: (1) Complete failure of leaf devel- 

 opment (longest infestation); (2) production of twisted and speckled leaves (infested for 

 1 season); (3) production of flecks here and there on the blades (infestation of current year). 

 Such flecks differ from ordinary leaf spots by being characteristically thickened or swollen 

 instead of depressed. The effects of attack on the bulbs are described in detail, although 

 they are chiefly internal and considered less reliable for diagnostic purposes than leaf lesions. 

 — Evidence is presented that the parasite was introduced into Holland from England about 

 1909, and that it became of marked importance in 1916. The relation of this parasite to the 

 nematode long known in Holland as the cause of "ring" or "old" disease of hyacinth is dis- 

 cussed, and an attempt made to decide on experimental evidence whether the nematodes are 

 identical, 2 biological forms of the same species, or 2 distinct species. In the experiments, 

 conducted in 2 series for 3 seasons, healthy narcissus and hyacinth bulbs were exposed under 

 controlled conditions to nematodes from the 2 respective hosts. In no case did the nematode 

 from narcissus attack hyacinth, or vice versa. Amaryllis, Iseme, and Galanthus (Amaryl- 

 lideae), tested in similar cross-inoculation experiments, were attacked by the narcissus 

 nematode only. Nematodes from naturally infested bulbs of these hosts were able to attack 

 narcissus but not hyacinth bulbs. The conclusions are that this parasite of narcissus has 

 not resulted from an adaptation en masse by the hyacinth nematode, that the narcissus form 

 has not originated by mutation from the hyacinth form, that the nematode of narcissus is 

 biologically distinct, and that, should morphological distinctions be discovered, specific 

 names should be given to indicate the existence of distinct organisms. — The removal of dis- 

 eased plants and immediately adjacent healthy ones, as well as replacement of the infested 

 surface soil, is recommended. Chemicals failed to disinfect the soil, and heating appears too 

 expensive for large scale application. Turning under the soil is of doubtful efficiency, since 

 even the deepest and most careful spading does not entirely prevent infection. However, 

 this method is recommended where replacement of the infested layer with clean soil is not 

 feasible. Disinfecting bulbs by hot air and hot water treatments was tried, with promising 

 results. The difficulty of maintaining uniform temperatures with large quantities of bulbs 

 in the hot water treatment was overcome by means of a specially devised thermo-regulator, 

 which is described and figured. In such treatments the size and condition of bulbs are im- 

 portant factors. The heating tends to hasten growth and blooming as well as bringing about 

 control of the yellow disease {Pseudomonas hyacinthi). — H. H. Whetzel. 



1902. Verhoeven, W. B. L. Plantenziekten, waarmede rekening moet worden gehouden 

 bij de veldkeuring. [Plant diseases which should be considered in field inspection.] Tijdschr. 

 Plantenz. 26: 149-159. PI. 8-10. 1920. — Field characteristics of the common diseases of 

 cereals and field legumes are briefly described, and the standard methods for control in each 

 case given. The 1st part of the paper deals with cereal smuts and the stripe disease of barley. 

 Rusts are not treated. Wheat affected with stinking smut is said to be more severely attacked 

 by rusts than the non-smutted plants. Copper sulphate treatment is recommended for 

 stinking smut of wheat and covered smut of barley, while for oat smut, hot-water treatment 

 is preferred to formaldehyde. Where stinking smut and loose smut of wheat or the naked 

 and covered smuts of barley occur together both copper sulphate and hot water treatment 

 must be applied. — Bean anthracnose (Colletoirichum lindemuthianum) , blight of peas {Asco- 

 chyta pisi), and clover anthracnose {Colletoirichum sp.) are discussed in the 2nd part of the 

 article. The author recommends further investigation of several diseases, viz., Gibber ella 

 disease of oats, root rot of beets (Phomabetae), flax anthracnose {Colletoirichum lirii), and 

 mosaic disease of beans. — H. H. Whetzel. 



