Inwieweit besteht eine Gesundheitsgefährdung des Menschen durch neuzeitliche Pflanzenschutzmittel?

Ohne Zusammenfassung     

Einige neue Erkenntnisse über die Bionomie der europäischen Monochamus-Arten (Col. Cerambyc.)1)

Ohne ZusammenfassungVortrag gehalten beim ersten Südtiroler Entomologentag in Dietenheim, 22. September 1970.I 39042 Brixen, Prov. Bozen/Italien, Rienzdamm 38     

Nitrogen uptake from 15N-enriched fertilizer by four tree crops in an Amazonian agroforest

Mixed tree cropping systems have been proposed for sustainable nutrient management in the humid tropics. Yet, the nutrient interactions between intercropped trees have not been addressed sufficiently. In the present study we compare the temporal and spatial patterns of the uptake of applied ¹⁵N by four different tree crops in a mixed tree cropping system on a Xanthic Ferralsol in central Amazônia, Brazil, during one year. Most of the N uptake occurred during the first two weeks. Very little N was recovered by peach palm (Bactris gasipaes), more by cupuassu (Theobroma grandiflorum) and annatto (Bixa orellana) and most by Brazil nut (Bertholletia excelsa). Due to tree pruning the total accumulation of applied ¹⁵N in the above-ground biomass of annatto decreased throughout the year. It remained constant in cupuassu and peach palm and increased in Brazil nut. Brazil nut showed an extensive root activity and took up more fertilizer N applied to neighboring trees than from the one applied under its own canopy in contrast to the other three tree crops. Therefore, trees with wide-spread root systems may not need to receive N fertilizer directly but can take up N applied to other trees in the mixed cropping system. This means that such trees may effectively decrease N leaching when intercropped with trees that have dormant periods or places with low N uptake, but also exert considerable resource competition.This revised version was published online in November 2005 with corrections to the Cover Date.     

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     

Untersuchungen über das Auftreten und die Lebensweise des WellenbockesSemanotus undatus L.(Col., Cerambycidae)

Zusammenfassung Anhand der Analyse einer stark befallenen Fichte(Picea excelsa), wurde eine eingehende Untersuchung über die Bionomie vonSemanotus undatus L. durchgeführt. Die Art befällt zusammen mit verschiedenen Borkenkäfern. der GattungPityogenes, Pityophthorus undPolygraphus, kürzlich abgestorbene Nadelhölzer. Die Weibchen legen im Frühjahr an die 30 weißliche, 1,6 mm lange Eier einzeln unter Rindenschuppen ab, aus denen nach 1–2 Wochen die Eilarven schlüpfen. Die Larven minieren zwischen Rinde und Splint (Abb.) und gehen nach Abschluß ihrer 2–4 monatigen Fraßtätigkeit zur Verpuppung mit einem Hakengang (Abb.) 2–8 cm tief ins Holz. Der Großteil der Larven verpuppt sich schon im August/September, der nach dreiwöchiger Puppenruhe schlüpfende Käfer überwintert dann in der Puppenwiege, die er erst im kommenden März/April verläßt. Etwa 1/3 der erwachsenen Larven ü berwintert jedoch im Larvenstadium und verpuppt sich erst im nächsten Frühjahr. Dieses unterschiedliche Verhalten in der Überwinterungsform ist zum Teil temperaturbedingt und führt im Mai/Juni zu einer zweiten verspäteten Erscheinungswelle der Käfer. Die Käfer haben eine Aktivitätsperiode von 1–3 Wochen, während der sie keinerlei Nahrung zu sich nehmen. Der durch die Hakengänge verursachte technische Schaden gleicht dem derTetropium-Arten, reicht aber durch das viel sporadischere Auftreten dieser boreomontanen Art in seiner Bedeutung bei weitem nicht an den vonTetropium verursachten heran.     

A comparison of two stand table projection methods for young Eucalyptus nitens (Maiden) plantations in Chile

The study compares two methods of stand table projection based on data from young Eucalyptus nitens (Maiden) plantations in Chile. The projected diameter distributions were estimated using the methods proposed by Nepal and Somers (1992) [For. Sci. 38 (1992) 120] and Cao and Baldwin (1999) [For. Sci. 45 (1999) 506]. The evaluation compared the observed and estimated diameter distributions for different projection intervals, using the Kolmogorov–Smirnov test and an error index called ‘relative discrepancy’. The evaluation showed that both methods are suitable for application in the Eucalypt plantations. However, the method proposed by Nepal and Somers proved to be more accurate, especially when the projection period extends over 4 years or more. Expected error and bias for the observed and estimated total and merchantable volumes at stand level were also evaluated. The observed error and bias were relatively low for both methods; however, some differences were detected when the volume distributions were analyzed at diameter class level.     

Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica

The agroforestry systems of cacao (Theobroma cacao) under laurel (Cordia alliodora) and cacao under poro (Erythrina poeppigiana) were studied at CATIE, Turrialba, Costa Rica. An inventory was taken of the organic matter and nutrients (N, P, K, Ca, and Mg) separating the species into their compartments (leaves, branches, trunks and roots). Studies of the litter and of the mineral soil (0–45 cm) yielded these results: Patterns of nutrient accumulation are discussed in relation to the characteristics of these agroforestry systems.     

Decomposition of needle/leaf litter from Scots pine, black cherry, common oak and European beech at a conurbation forest site

Litter decomposition was studied for 2 years in a mixed forest serving as a water protection area (Rhine-Neckar conurbation, SW Germany). Two experiments differing in initial dry weight equivalent in litterbags were set up: one to compare decomposition of European beech leaves (Fagus sylvatica) with common oak leaves (Quercus robur), and the other comparing decomposition of Scots pine needles (Pinus sylvestris) with black cherry leaves (Prunus serotina Ehrh.), respectively. Mass losses were greater for oak litter than for beech (75.0 versus 34.6%), and for cherry litter than for pine (94.6 versus 68.3%). In both experiments, a strong initial loss of soluble compounds occurred. The changes in litter N and P concentrations and the decrease in C-to-N ratio coincided with changes in residual mass. However, neither tannin and phenolic concentrations nor NMR could explain the pronounced variation in mass loss after 2 years. Differences in litter palatability and toughness, nutrient contents and other organic compounds may be responsible for the considerable differences in residual mass between litter types. The fast decay of black cherry leaves appears to play a major role in the present humus dynamics at the studied site. Since black cherry has a high N demand, which is mainly met by root uptake from the forest floor, this species is crucial for internal N cycling at this conurbation forest site. These effects together may significantly contribute to prevent nitrate leaching from the forest ecosystem which is subject to a continuous N deposition on an elevated level.     

A case study of forest management planning using a new heuristic algorithm

We present an approach to generate and evaluate different silvicultural development paths and to optimize the development of a Norway spruce stand, using a long-term planning horizon. To generate a silvicultural path, the maximum stand density was applied. At each thinning event, three possible thinning intensities (10, 20, 30% of the stem number per ha) were randomly chosen. A search algorithm known as modified Accelerated Simulated Annealing (mASA) was used to estimate the optimum combination of stand paths for a given forest as a whole. Production and economic management objectives were considered and then compared. The economic criterion was the Expected Stand Value (ESV) with a 4% discount rate. The generated data set of 38 Norway spruce stands (comprising a total of 123.8 ha) was used in the case study. The result with the best combination of paths was presented in a digitized forest map. Forest management simulation was performed using a specially developed computer program, for a planning horizon of 20 years. The mASA proved to be an effective search method for identifying optimum paths.