Die Heberkause und Berechnung von Sperr- und Klausmauern aus ihre Bogenwirkung

Ohne Zusammenfassung     

Termiten aus Kolumbien nach Beobachtungen von German O. Valenzuela und Fritz Schremmer

Zusammenfassung Von den vier besprochenen Termitenarten werdenSyntermes aculeosus Emerson undCornitermes acignathus Silvestri zum ersten Mal aus Kolumbien gemeldet.Comatermes perfectus (Hagen) wird zum ersten Mal als Schädling an Kaffeepflanzen beschrieben, die auf frisch gerodeten Urwaldboden angepflanzt wurden. Der Schaden erstreckt sich auf den Wurzelhals 10–12 cm unter bis 5–7 cm über der Erdoberfläche. Dabei wird die Wurzel zum größten Teil vom Stamm getrennt, der allerdings sekundäre Seitenwurzel bildet.Amitermes foreli Wasmann baut große oberirdische Lehmnester auf der offenen Savanne, die an die Kompaßnester in Australien erinnern. Arbeiter und Soldaten vonS. aculeosus werden von den Indianern gegessen.C. acignathus wurde in einem verrotteten Baumstamm gefunden, scheint aber nicht schädlich zu werden.

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Termites from Colombia observed by German O. Valenzuela and Fritz Schremmer

Comatermes perfectus (Hagen) (Kalotermitidae) is an important pest on living coffee plants in young plantations destroying the root collar.Amitermes foreli Wasmann (Termitidae, Termitinae) build large epigeous mud nests in the open savanna similar to the magnetic or compass nids in northern Australia. The workers and soldiers ofSyntermes aculeosus Emerson (Termitidae, Nasutitermitinae) are eaten by Indians in southern Colombia. This species andCornitermes acignathus Silvestri are the first records from Colombia.

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Mit 4 Abbildungen     

Schnittholzqualität und Furniereignung von Douglasien aus linksrheinischen Anbaugebieten

Summary Douglas fir sample trees from 9 various stands were cut in sawmills. Every board of the converted timber was graded; all defects in timber were analysed, especially all black and sound knots on the surface of the boards were measured. The percentage of good boards prooved to be comparatively low. From fertile sites the sawn timber quality seems to be inferior compared with wood from poorer and dryer sites. Douglas firs grown single between broadleaved stands showed the lowest timber quality. Throughout the quantity and thickness of black knots were responsible for poor quality. Experiments with production of veneer yielded useful carved veneers when sliced of quartered and clear logs. Branchless logs from 80 years old Douglas firs could be worked up to carved veneers, but are too young for peeled veneers. For full veneer logs diameters of 70 cm and structure of small annual rings is essential. For saw timber as well as for veneerwood production short rotation below 120 years is not suitable. Moreover pruning is necessary.      

Zur Polyphagle der Engerlinge von Melolontha melolontha L. an Pflanzen aus Wiese und Ödland

Experiments on polyphagous habits of white grubs (Melolontha melolontha L.) on plants of grassland The effect of feeding roots of different grassland plants on white grubs was studied in the laboratory. Weight increase and mortality of the larvae were recorded. These data show that the feeding on roots of weeds, especially dandelion (Taraxacum officinale W.) led to a higher weight increase and lower mortality than the feeding on roots of grasses. There were, however, differences between the three larval stages.

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Die Untersuchungen wurden durch die Unterstützung der Deutschen Forschungsgemeinschaft ermöglicht, der wir auch an dieser Stelle danken.

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Vortrag auf der Entomologentagung Gießen, 8. bis 12. März 1976.     

Mild: und Maidmannsbilder. Jagdfcenen und Schilderungen aus Mald, Eefild und H?hen. Mit Jlluftrationen von Merner, Rold, Hildebrand u. A. 185 S. Leipzig (ohne Jahreszahl). Berlag von C. Miuferodt. Preis 1 Ihlr. 10 fgr.

Ohne Zusammenfassung     

Intersterilitätsgruppen und Klone von Heterobasidion annosum-Isolaten aus Koniferen- Wurzel- und -Stammfäulen

Intersterility groups and clones of Heterobasidion annosum isolates from root and butt rots of conifers 69 H. annousum heterokaryons from scots pine, Douglas fir, Norway spruce and larch belonged to the P group, three heterokaryons from Norway spruce to the S group. The results of a study with clones of H. annosum isolates from roots of Scotch pine trees in close neighbourhood suggest colonisation by H. annosum (partly) via root contacts.     

Rasterelektronenmikroskopische Untersuchungen an von Vorratsschädlingen angegriffenen Verpackungsfolien aus synthetischen Kunststoffen und abgewandelten Naturstoffen

Packaging foils made of cellulose actetate, cellophane, polyethylene, polypropylene, polystyrene, polyester, polyvinyl chloride, attacked byRhizopertha dominica F.,Stegobium paniceum L.,Tribolium castaneum Hbst. and larvae ofPlodia interpunctella Hbn. were examined with the scanning electron microscope (SEM). Because of the destruction marks made by the insects, it is possible to determine with the SEM the side of packaging material which has been attacked by the pests. Due to the shape and position of the mouthparts of the insects the gnawing marks are rather typical for the different species. By means of a standard of comparison it might be possible to determine the family and perhaps the genus or species of the insects involved. The influence of shape and size of the mouthparts as well as the position of the mandibles in relation to the anatomy and to the axis of the body on the gnawing ability of stored-product pests is discussed. The reasons for the insect resistance of packaging materials are discussed (smoothness of the surface, rigidity, thickness).     

Hemmung einiger Ektoenzyme von Fomes annosus (Fr.) Cke. durch Holz- und Bastextrakte aus Picea abies (Karst.)

Inhibition of several ectoenzymes of Fomes annosus (Fr.) Cke. by wood and bark extracts from Picea abies (Karst.). Methanol soluble extractives of sapwood, heartwood and reaction zone from Norway spruce as well as acetone soluble extractives of spruce bark were tested at a concentration of 0.05 percent for inhibition of Fomes annosus enzymes cellulase, pectinase