253 



Appel (— ). Die wirtschaftliche Bedeutung der Pflanzenkrankheiten 

 und die Mittel zu ihrer Bekampfung. [The Economic Importance 

 of Plant Diseases and the Means for combating them.]— Separate 

 from Arb. Deutschen Landw. Ges., no. 314, 1921, 18 pp. 



In Germany there is no universal legislation on plant protection, 

 so that the direct intervention of the State is not possible except 

 where Imperial legislation exists in a few cases, such as that respecting 

 the vine-louse [Phylloxera], Colorado potato beetle [Leptinotarsa 

 decemlineata] and San Jos6 scale [Aspidiotus perniciosiis]. At the 

 present time the chief service rendered in plant protection is educational 

 in character. The results have proved satisfactory, there being a 

 great demand for instructive literature on the part of agriculturists. 



Appel (— ). Die Organisation des Pflanzenschutzes im Deutschen 

 Reich. [The Organisation of Plant Protection in the German 

 Empire.]— Separate from Arb. Deutschen Landw. Ges., no. 314, 

 1921, 18 pp. 



A brief account is given of the organisation of plant protection 

 work in Germany since its inception in 1889. 



Thiem (H.). Die Frostspannerplage im Niederungsgebiet der Weichsel 

 bei Marienwerder Wstpr. und Beitrage zur Biologic des kleinen 

 Frostspanners. [The Winter Moth Outbreak in the low-lying 

 Vistula Region near Marienwerder, West Prussia, and Contri- 

 butions to the Biology of Cheimatobia brumata.] — Arb. Biol. 

 Reichsanst. Land- u. Forstwirtsch., Berlin^ xi, no. 1, 1922 94 pn 

 10 figs. ' ^^" 



This outbreak of Cheimatobia brumata, L., occurred from 1916 to 

 1920 in the low-ljnng Vistula region near Marienwerder. The losses 

 from 1916 to 1919 amounted to ;^90,000 (at par), while remedial 

 measures in 1919 and 1920-21 cost ;^2,325 (at par). 



The complete eradication of C. brumata in this district is not possible, 

 but general banding can— if properly applied— eradicate it in the 

 orchards and along the roads. Generally speaking, the autumn bands 

 should be applied in western Germany by 25th October, in central 

 Germany by the 20th, and in eastern Germany by the 15th. The 

 spring bands must be arranged about mid-March in years when the 

 weather is mild and favours egg development. The date is indicated 

 by the dark coloration of the reddish-yellow eggs below the banding. 

 The autumn bands must be kept in condition up to mid- January 

 and the spring ones up to mid-May. Banding must include those 

 trees that are food-plants of C. brumata as well as infested ones. 

 All worthless plants should be destroyed, and such bushes as are of 

 economic value, but difficult to band, require special treatment. 



Spraying with fruit-tree carbolineum did not give satisfactory 

 results. The flight of the moths increases with a rising temperature. 

 With the advent of cold weather or snow more females than males 

 appear in the open. A thaw after a sharp frost induces a great increase 

 in flight. Excessive dampness of the ground or a sudden thaw kills 

 more males than females. Female moths can support a temperature 

 of — 14-9°C. [5°F.]. Oviposition usually occurs immediately after 

 mating and in the crown, though it sometimes takes place on the trunk. 

 One female may oviposit on several trees, but no special choice for 

 any given variety of fruit-tree was noticed. Fertilised eggs turn from 



