Versuche zur Bekämpfung von Gewächshausschildläusen mit systemischen Insektiziden

Zusammenfassung In Versuchen zur Bekämpfung der in Gewächshäusern verbreiteten SchmierlausP. maritimus und der NapfschildlausC. hesperidum mit systemischen Insektiziden wurde festgestellt, daß durch Gießen bessere Ergebnisse erzielt werden als durch Bandagieren oder Spritzen. Rogor 40 erwies sich in 0,1- und 0,05%igen Konzentrationen durchweg als wirksamer als das Versuchspräparat B 5122 (Karbamat). Das zuletzt genannte Mittel bewirkte in den genannten Konzentrationen oft phytotoxische Erscheinungen. Mit Metasystox (i) bzw. Dimecron konnte nur ein geringer Erfolg bzw. keine Wirkung erzielt werden. Die Mortalität vonC. hesperidum an Papayapflanzen nach Gieß en mit Insektiziden erwies sich auf Blattspreiten am höchsten, am Sproß als geringer und am Blattstiel am geringsten. Durch Behandlung einer faserigen Pflanzenart wie Papaya mit systemischen Insektiziden wurde eine bessere Wirkung gegenC. hesperidum erzielt als an einer verholzten wie Zitrus und krautigen wie Rübe.

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Summary In experiments to control the mealybugP. maritimus and the soft scaleC. hesperidum by the use of systemic insecticides it was found that better results can be obtained by pouring the solution (soil treatment) than by bandaging (trunk application) or by spraying (foliar application). Rogor 40 proved at 0.1- and 0.05% concentrations to be generally more effective than the carbamate B 5122. The latter caused in given concentrations often phytotoxic symptoms. Only a moderate or no success could be achieved by the use of Metasystox (i) and Dimecron respectively. The mortality ofC. hesperidum which resulted after pouring the papaya plants with insecticides was maximum on leaves, lesser than that on stems and the least on leaf petioles. The effect of systemic insecticides againstC. hesperidum seems to be better on a fibrous plant type (papaya) than on a woody type (citrus) or lastly on a harbaceous (beet) plant.

     

Antifeedant activity and toxicity of leaf extracts from <Emphasis Type="Italic">Porteresia coarctata</Emphasis> Takeoka and their effects on the physiology of <Emphasis Type="Italic">Spodoptera litura</Emphasis> (F.)

Antifeeding and toxic effects of chemical extracts from Porteresia coarctata Takeoka on the insect pest Spodoptera litura (F.) were investigated in the laboratory. Hexane extracts of P. coarctata leaves were re-dissolved in dimethyl sulfoxide and applied in water to leaves of Ricinus communis L. (castor). A concentration of 1,000 and 2,000 ppm extract exhibited significant antifeeding and toxic effects to third instar larvae when compared to the same concentration of dimethyl sulfoxide in water as control. One day after feeding on extract-treated castor leaves, the mortality of S. litura larvae was 50%. Mortality increased to 95% after 11 days at a dosage of 2,000 ppm. Compared to the control, third instar larvae fed on castor leaves treated with P. coarctata leaf extract at different concentrations showed significant reduction in protein and DNA content in the fat body and midgut tissues. Results demonstrate the insecticidal and antifeedant properties of P. coarctata leaf extract against the generalist pest S. litura leading to biochemical changes in the insect body. Thus, P. coarctata contains phytochemicals, and the extract, in crude and pure form, has potential as a botanical insecticide in alternative control strategies against Lepidoptera pests.     

From Forests to Food Security: Pathways in Nepal’s Community Forestry

There is an increasing recognition of the contribution of forests to food security of poor and marginalized people. However, empirical findings remain limited on how forests contribute to food security. Drawing on four case studies of community forestry in Nepal, this paper discusses pathways through which forests are contributing to food security needs of local communities. The evidence presented here was gathered through 4 years of action research and draws insights from the past 40 years of Nepal’s community forestry practice, which is often regarded as a successful case of conservation and development. It is shown that there are four distinct pathways through which community forests contribute to food security as a source of: (1) income and employment; (2) inputs to increase food production; (3) directly for food; and (4) renewable energy for cooking. Despite emerging pathways linking forest management to food systems at the local level, forestry policies and institutions have neither explicitly recognized nor strengthened the linkage between forest and food security. The paper highlights that there is a need for a fundamental shift in thinking from the conventional notion of ‘forests for soil conservation’ to ‘sustainable forest management for food security’.     

Versuche über den Einfluß von Bodenart und Bodenmenge auf die Aufnahme systemischer Insektizide durch die Pflanzevon Bodenart und Bodenmenge auf die Aufnahme systemischer Insektizide durch die Pflanze

Zusammenfassung In Versuchen mit vier Bodenarten und verschiedenen Bodenmengen wurde festgestellt, daß systemische Insektizide von Ackerbohnenpflanzen aus leichteren, sandigen Böden rascher und in großerer Menge aufgenommen werden als aus humushaltigen schweren. In kleineren Bodenmengen wirkten die Insektizide länger als in größeren.

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Summary In experiments with four types and different amounts of soils it could be found that the uptake of systemic insecticides by broad bean plants was quicker and more intensive from lighter sandy soils than from heavier humus rich soils. The insecticides persisted in the latter much longer than in the former. The duration of the effect of the systemics was longer in lesser amounts of soils than in greater ones.

     

Studies on Maize-Legume Intercropping and their Residual Effects on Soil Fertility Status and Succeeding Crop in Upland Situation

To examine the advantages of cereal-legume intercropping system with maize as main crops, field studies conducted for two years on sandy upland loamy soils in Bihar plateau, India, indicated maize-groundnut as the best system. Yield advantages were noticed between 22–44 % over sole maize cropping. Different production indices largely indicated the same pattern in ranking intercropping treatments. Of the other legumes used, mung also showed potential whereas cowpea and soyabean did not. Increasing cropping intensities through use of interspace by legume did not significantly reduce maize yield, particularly in combination with groundnut and mung. Soil nitrogen enrichment through legume cultivation could be noted through examination of soil test values and yield of succeeding wheat crop. Wheat, however, did not show its promise as a follow-up crop without input of water and fertilizer.     

Effects of Spreading Out Termite Mound Material on Ferralsol Fertility,Katanga, D.R. Congo

Around Lubumbashi, the introduction of large-scale pivot-irrigated agriculture entails leveling of large termite mounds during field preparation. The effect on soil fertility and crop yield (Solanum tuberosum and Alium cepa) is evaluated along 11 transects extending from a former termite mound location to reference soil that received no termite mound material. Spreading mound material was found to increase the pH, calcium carbonates CaCO₃ content, and the amount of resin-extractable phosphorus (P), other possible effects being undone by fertilizer application. On the other hand, poor physical properties of the mound material seem to have adverse effects on crop production. While the benefits of spreading out mound material seem limited for large-scale farmers with access to fertilizers, the use of mound material may present an opportunity to resource-poor farmers throughout the miombo eco-region, provided that the application of mound materials is optimized and that any adverse effect on soil physical properties can be mitigated.     

Operationalizing a Framework for Assessing the Enabling Environment for Community Forest Enterprises: A Case Study from Nepal

Small-scale Forestry - We demonstrate how Baynes et al.’s (Glob Environ Change 35:226–238, 2015. https://doi.org/10.1016/j.gloenvcha.2015.09.011) framework can be operationalized as a...     

Fluorescence-based method, exploiting lipofuscin, for real-time detection of central nervous system tissues on bovine carcasses

The removal of central nervous system (CNS) tissues as part of bovine spongiform encephalopathy (BSE) risk material is one of the highest priority tasks to avoid contamination of the human food chain with BSE. No currently available method enables the real-time detection of possible CNS tissue contamination on carcasses during slaughter. The fluorescent pigment lipofuscin is a heterogeneous, high-molecular weight material that has been shown to be enriched in high concentrations in neuronal tissues. In this study, lipofuscin fluorescence was investigated as a marker for real-time detection of CNS contamination. Front-faced fluorescence spectra of brain and spinal cord samples from 11 cattle gave identical, reproducible fluorescence signal patterns with high intensities. The specificity of these spectra was assessed by investigating 13 different non-CNS tissues enabling the differentiation of brain and spinal cord by signal intensity and structure of the spectra, respectively. Small quantities of bovine spinal cord were reliably detected in the presence of raw bovine skeletal muscle, fat, and vertebrae. The presented data are a fundamental basis for the development of a prototype device allowing real-time monitoring of CNS tissue contamination on bovine carcasses and meat cuts.