467 



slow until recently, when the damage done became marked, though 

 confined to potatoes. The condition of the affected plants is described. 

 Infestation by this Nematode was accompanied by that of a mite, 

 Rhizoglyphus echinopus. 



Crop rotation is advised, potatoes not being planted oftener than 

 once in three years. Deep trenches will prevent a spread of the pest. 

 All debris from potato fields must be burned, and potatoes from 

 infested plots must not be used for seed. 



Gegen die Geheimmittel im Pflanzenschutz, [Against Secret Remedies 

 in Plant Protection.] — Zcitschr. Pfianzenkr. Stuttgart, xxx, no. 4-5, 

 19-20, pp. 146-117. 



The German Society for Applied Entomology has submitted 

 to the Imperial Chancellor a memorandum pointing out the evils 

 accruing through the sale of secret remedies for plant diseases and pests . 

 Animal pests alone of agriculture and forestry cause an annual loss of 

 £25,000,000 in Germany, and this loss is increased by the use of worth- 

 less specifics. The memorandum, which was signed by Prof. Escherich 

 and Dr. Stellwaag on behaK of the Society, calls for the prohibition 

 of any compound not duly authorised by a competent authority. 



WiLHELMi (J.). Die angewandte Zoologie als wirtschaftlicher, 

 medizinisch-hygieniseher und kultureller Faktor. [Applied 

 Zoology as an economic, medico-hygienic and cultural Factor.] 

 — Berlin, J. Springer, 1919, 88 pp. Price 5 Marks. (Review in 

 Zeitschr. Pjlanzenkr. Stuttgart, xxx, no. 4-5, 1920, p. 172.) 



The necessity for basing measures against injurious insects on their 

 biology is emphasised in this booklet. Control by means of natural 

 enemies is not always the best. The enormous importance of apphed 

 zoology is referred to in the last chapter, and a claim is made for its 

 mclusion among the university courses. Dr. Reh, the German 

 reviewer, points out that one man cannot properly deal with so wide 

 a subject as applied zoology. The zoology of plant pests, excluding 

 parasites of animals, is a sufficiently wide subject for a single 

 individual to cope with, 



WoHLBOLD (H.). Forstschadlinge. [Forest Pests.] — Leipzic, Hach- 

 meister & Thai. (Review in Zeitschr. Pjlanzenkr. Stuttgart, 

 xxx, no. 4-5, 1920, p. 173.) 



WoHLBOLD (H.). Landwirtschaftliche Schadlinge. [Agricultural Pests.] 

 — Idem. 



The first part of the booklet on forest pests deals with general 

 considerations concerning the interrelation of plant and animal life 

 in forests, and the dependence of the latter on the former. The 

 subject of mammalian, avian and insect pests and their control is then 

 briefly dealt with. Combative measures should only be taken against 

 persistent enemies, not against animals responsible only for 

 occasional injury. 



The booklet on agricultural pests is also intended for lay readers, 

 especially those who are practical agriculturists. 



(717) a2 



