Christian Ulrichs

Christian Ulrichs
Humboldt-Universität zu Berlin | HU Berlin · Department of Crop and Animal Sciences

Prof. Dr. Dr.

About

318
Publications
85,290
Reads
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4,233
Citations
Citations since 2017
66 Research Items
2385 Citations
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20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
Additional affiliations
January 2003 - present
Humboldt-Universität zu Berlin
October 2001 - December 2012
United States Department of Agriculture
Position
  • Research Associate
April 1998 - September 2001
Technische Universität München
Position
  • PhD student and postdoctoral fellow

Publications

Publications (318)
Article
In Ghana major stored product insect pests of maize and rice are controlled by the use of synthetic insecticides which are very expensive for farmers, might affect worker safety if not properly applied due to lack of technical know-how. Moreover, its use might eventually lead to some toxic residues in the end product for human consumption. In an at...
Article
Full-text available
With the worldwide industrialization of black soldier fly (BSF) production, it is necessary to better understand how the rearing scale and larvae density influence the performance of larvae and the quality of the final product. In this study, a factorial experiment was conducted to test the effect of rearing scale and density on the growth and comp...
Article
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Social cohesion plays a key role in processes of peacebuilding and sustainable development. Fostering social cohesion might present a potential to enhance the connection of natural resource management and peacebuilding and better functioning of sustainable land use systems. This contribution explores the nexus between social cohesion, natural resou...
Article
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Salix cortex-containing medicine is used against pain conditions, fever, headaches, and inflammation, which are partly mediated via arachidonic acid-derived prostaglandins (PGs). We used an activity-guided fractionation strategy, followed by structure elucidation experiments using LC-MS/MS, CD-spectroscopy, and 1D/2D NMR techniques, to identify the...
Article
Fresh-cut fruits are highly perishable and show a short shelf life. Therefore, storage in sugar syrup is commercially used to delay undesirable metabolic changes and to prevent browning. Investigations on the effects of syrup application on volatile organic compounds (VOCs), important for the consumers’ acceptance, are rare. It is, however, known t...
Article
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The usefulness of anti-inflammatory drugs as an adjunct therapy to improve outcomes in COVID-19 patients is intensely discussed in this paper. Willow bark (Salix cortex) has been used for centuries to relieve pain, inflammation, and fever. Its main active ingredient, salicin, is metabolized in the human body into salicylic acid, the precursor of th...
Article
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Willow bark is traditionally used for pharmaceutical purposes. Evaluation is so far based on the salicylate content, however, health promoting effects of extracts might be attributed to the interaction of those salicylates with other compounds, which support and complement their action. So far, only S. purpurea , S. daphnoides , and S. fragilis are...
Article
Three diatomaceous earths (DEs), InsectoSec®, Diatomeenerde Probe-A and Fossil Shield® 90.0, were tested in the laboratory against Callosobruchus maculatus (Coleoptera: Chrysomelidae) from Ghana. Application rates on stored cowpea were 0.05%, 0.1%, 0.2% and 0.3% wt/wt. Adult mortality was recorded after 13–16 d, progeny production after 6 weeks. In...
Article
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The carrot psyllid Trioza apicalis Förster 1848 is a carrot pest in Europe that can cause serious damages in case of massive occurrence. Damages up to a total loss of yield have been reported from Scandinavian countries but also from Switzerland. The action threshold to control the pest with chemical pesticides is 0.2 T. apicalis per day and trap c...
Article
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Onset of salinity induces the pH of the leaf apoplast of Pak choi transiently to increase over a period of 2 to 3 hr. This pH event causes protein abundances in leaves to increase. Among them are enzymes that are key for the phenylpropanoid pathway. To answer the questions whether this short‐term salt stress also influences contents of the underlyi...
Article
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Environmental factors and cultural practices significantly influence the secondary metabolites in plants, e.g., glucosinolates, depending on the cultivar of each species. The present study analyzed the influence of specific environmental factors (e.g., temperature, rainfall, and relative humidity), elevation, and fertilization (i.e., nitrogen and s...
Article
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The assessment of tomato fruit quality depends on a variety of extrinsic and intrinsic quality parameters such as color, firmness and sugar content. Conventional measurement methods of these quality parameters are time consuming, require various measurement de-vices, and in case of intrinsic quality, involve destructive measurements. Latest researc...
Article
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Four silica-based acaricides were examined in laboratory tests for their effectiveness against poultry red mite, Dermanyssus gallinae. All acaricides resulted in 100% mite mortality. Two groups of active ingredients could be differentiated. The products Silicosec® and Ewazid®, based on naturally occurring diatomaceous earth (DE), killed 100% of adu...
Article
Tropospheric ozone is an important ambient atmospheric pollutant component in urban areas. Determining plant reactions to ozone in plant growth and biochemical quality contents plays an important role in understanding plant metabolism. This study aimed to provide an understanding of the effect of ozone on early vegetative growth stage Pak-Choi (Bra...
Article
The bark of willows (Salix spp.) is rich in bioactive phenolic compounds from different compound classes and is therefore used as an herbal remedy. The accumulation of these secondary plant metabolites is influenced by environmental factors, including the availability of water. To analyze the influence of drought stress on the profile of phenolic m...
Article
Lycopene, the red colored carotenoid in tomatoes, has various health benefits for humans due to its capability of scavenging free radicals. Traditionally, the quantification of lycopene requires an elaborate extraction process combined with HPLC analysis within the laboratory. Recent studies focused simpler methods for determining lycopene and util...
Article
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The pulse beetle, Callosobruchus maculatus F. is a key pest to stored Kersting's groundnut, Macrotyloma geocarpum Harms. There are many reports evaluating various diatomaceous earths (DEs) against stored product pests, but there is limited information on the efficacy of these materials against C. maculatus and none on Kerstings groundnut. Laborator...
Article
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One of the most vital environmental factors that restricts plant production in arid and semi-arid environments is the lack of fresh water and drought stress. Common bean (Phaseolus vulgaris L.) productivity is severely limited by abiotic stress, especially climate-related constraints. Therefore, a field experiment in split-plot design was carried o...
Article
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Cowpea aphid, Aphis craccivora, is a major cowpea pest. Cowpea-cereal intercrop alone does not effectively manage the pest. Use of pesticides in intercrop leads to health and environmental risks. Fungal-based biopesticides offer a better option because they are environment-and consumer-friendly. This study assessed the combined effect of Metarhiziu...
Conference Paper
Full-text available
Due to light conditions, cultivation of lettuce on the south side of the buildings is preferable. With regard to heavy metals, our study did not reveal any health risk due to consumption of lettuce produced under urban conditions with different air pollution levels. Nevertheless, the accumulation of heavy metals increased in unwashed and washed sam...
Article
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Two pot experiments were conducted in a greenhouse to examine 14C fixation and its distribution in biochemical leaf components, as well as the physiological and anatomical adaptability responses of wheat (Triticum aestivum L.) grown with seawater diluted to 0.2, 3.0, 6.0, and 12.0 dS m-1. The results showed significant reductions in chlorophyll con...
Article
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In practice, fresh-cut fruit and fruit salads are currently stored submerged in sugar syrup (approx. 20%) to prevent browning, to slow down physiological processes and to extend shelf life. To minimize browning and microbial spoilage, slices may also be dipped in a citric acid/ascorbic acid solution for 5 min before storage in sugar syrup. To preve...
Article
Full-text available
In practice, fresh-cut fruit and fruit salads are currently stored submerged in sugar syrup (approx. 20%) to prevent browning, to slow down physiological processes and to extend shelf life. To minimize browning and microbial spoilage, slices may also be dipped in a citric acid/ascorbic acid solution for 5 min before storage in sugar syrup. To preve...
Article
Full-text available
Processing, especially cutting, reduces the shelf life of fruits. In practice, fresh-cut fruit salads are, therefore, often sold immersed in sugar syrups to increase shelf life. Pre-processing short-term hot-water treatments (sHWT) may further extend the shelf life of fresh-cuts by effectively reducing microbial contaminations before cutting. In th...
Article
Full-text available
Processing, especially cutting, reduces the shelf life of fruits. In practice, fresh-cut fruit salads are, therefore, often sold immersed in sugar syrups to increase shelf life. Pre-processing short-term hot-water treatments (sHWT) may further extend the shelf life of fresh-cuts by effectively reducing microbial contaminations before cutting. In th...
Conference Paper
Full-text available
Entomopathogenic fungal (EPF) pathogens and natural enemies of arthropod pests complement each other in suppressing pest populations under natural environment. Commercial use of EPF based biopesticides requires registration and one of the criterion used is their safety to non-target organisms. In this study Metarhizium anisopliae (Metsch.) Sorok is...
Article
Determining plant reactions to atmospheric pollutants is important in predicting and planning for new horticultural production management programs and challenges in the future. A high level of ozone in the troposphere is considered the most phototoxic air pollutant, and has strong oxidative potential. This study aimed to provide understanding on th...
Article
Cowpea (Vigna unguiculata) production is constrained by biotic and abiotic factors, among which Cowpea aphid (Aphis craccivora) is ranked a key insect pest that severely limits its potential for provision of food and nutritional security to millions of people in sub‐Saharan Africa. The use of entomopathogenic fungi for A. craccivora management has...
Poster
Full-text available
Varying conditions of cultivation of vegetables inside a city’s boundaries were analyzed. As such, in the city of Berlin flower boxes with lettuce were installed at 20 spots at different heights, with different light conditions and air pollution levels. In order to exclude heavy metal uptake due to soil contamination, lettuce was seeded in a standa...
Conference Paper
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Zu den großen Herausforderungen des 21. Jahrhunderts gehört die Folgeneindämmung des durch Treibhausgasemissionen (THG-Emissionen) verursachten Klimawandels. Hierbei ist der Agrarsektor ein beachtlicher Emittent, darunter die wachsende Gewächshausbranche mit CO2-Emissionen. Daher erforscht und entwickelt das MinTHG-Konsortium, bestehend aus mehrere...
Poster
Full-text available
Zu den großen Herausforderungen des 21. Jahrhunderts gehört die Folgeneindämmung des durch Treibhausgasemissionen (THG-Emissionen) verursachten Klimawandels. Hierbei ist der Agrarsektor ein beachtlicher Emittent, darunter die wachsende Gewächshausbranche mit CO2-Emissionen. Daher erforscht und entwickelt das MinTHG-Konsortium, bestehend aus mehrere...
Article
Full-text available
Post-harvest management constraints are economically significant in Africa for a broad range of commodities, resulting in a substantial negative impact on food security and livelihoods. Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) coexists with Sitophilus oryzae (L.) (Coleoptera: Dryophthoridae) – they infest stored cereal grains, es...
Article
Willows are planted in short rotation coppices (SRC) to produce biomass. Another potential use of willows is the extraction of natural salicylates as alternatives to chemically synthesized acetyl salicylic acid (medical use). Available clones in Europe based on Salix viminalis L. do not contain salicylates and have high water requirements. In order...
Conference Paper
Full-text available
Post-harvest losses are economically significant in Ghana for a broad range of commodities, resulting in a substantial negative impact on food security and livelihoods. Maize grains are the main food crops that provide staple diet for the majority of the population. A nation-wide survey was conducted in the three different geographical zones of Gh...
Article
African nightshade (Solanum scabrum Mill.) is important for its nutrition, health promoting compounds and its contribution in providing a secure food supply and livelihood for smallholder farmers in rural, peri-urban and urban areas in Kenya. However, inadequate postharvest handling practices result in high losses. To address this issue, studies we...
Article
Cowpea, Vigna unguiculata ((L.) Walp; Fabales: Fabaceae), is an important indigenous vegetable and grain legume in the tropics where it represents a major diet component. Cowpea aphid, Aphis craccivora (Koch; Hemiptera: Aphididdae) is a major pest causing up to 100% yield losses. Aiming at establishing alternative approach to synthetic insecticides...
Article
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The highly competitive, adaptable and allergenic weed Parthenium hysterophorus (Compositae) is an invasive annual weed believed to be introduced to Ethiopia in 1970s. Field surveys, plant biodiversity impacts, and analysis of secondary plant compounds in P. hysterophorus and its possible impact on human health have been studied in Ethiopia since 19...
Poster
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Over time the human population has become increasingly urban. The proportion of city dwellers increased from 30% in 1950 to 66% in 2015. Due to this concentration of people in densely-built areas, a rethinking of agricultural and horticultural production is needed urgently. While the demand for fresh vegetables and other natural resources such as w...
Article
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Glucosinolates (GS) are secondary plant metabolites comprising different subgroups with opposing effects on human health. Hairy root cultures (HRC) are potent biotechnological tools allowing the biosynthesis of special substances under defined conditions. HRC of Eruca sativa, a brassicaceaous plant, were used to test different strategies to enhance...
Article
Sweet cherries are highly perishable fruit, consequently postharvest treatments are indispensable if longer shelf-life is desired. The use of synthetic fungicides is getting more and more repudiated, generating the demand for new sustainable and gentle “natural” sanitation techniques such as fumigation with acetic acid (AA). Not least due to still...
Article
Full-text available
Vegetable amaranth (Amaranthus cruentus L.) is gaining importance among the African indigenous leafy vegetables (AIVs) in the diets of many households in Africa. However, improper processing, handling, and storage of AIVs often result in faster deterioration thus high quantitative and qualitative losses with reduced availability of these highly nut...
Conference Paper
Full-text available
An increasing amount of greenhouse vegetables is produced using hydroponic systems. The used mineral fertilizers are often generated in energy consuming processes (esp. nitrate in Haber-Bosch) or gained from finite resources (esp. phosphate rock). Recovering the respective nutrients from waste streams is a promising option to make crop production m...
Article
Due to high perishability, African indigenous leafy vegetables (AIVs) tend to suffer heavy postharvest loss. There is a lack of information regarding management of loss of these vegetables. This study sought to identify, and assess, types and causes of AIV loss in the supply chain. The study was done across the AIV producing location of Nakuru, Kis...
Article
Full-text available
Three common plant species (Dieffenbachia maculata, Spathiphyllum wallisii, and Asparagus densiflorus) were tested against their capacity to remove the air pollutants toluene (20.0 mg m⁻³) and 2-ethylhexanol (14.6 mg m⁻³) under light or under dark in chamber experiments of 48-h duration. Results revealed only limited pollutant filtration capabiliti...
Conference Paper
Full-text available
The experiments described in this study are conducted on tomatoes and focus on the performance of a food-scanner (SCiO Molecular Sensor) compared to a benchtop NIR-spectrometer. Important quality parameters of tomato, such as sugar content and firmness, are evaluated with respect to their predictability in order to validate the performance of this...
Article
The aim of the present study was to evaluate two species of egg parasitoids under laboratory conditions for biological control of the Indian meal moth Plodia interpunctella, an emerging stored product pest in bulk grain. Trichogramma evanescens proved to be a better candidate for biological control compared to T. cacoeciae as it accepted and parasi...
Article
Full-text available
Food losses caused by insects during postharvest storage are of paramount economic importance worldwide, especially in Africa. Laboratory bioassays were conducted in stored grains to determine the toxicity of powders of Eugenia aromatica and Moringa oleifera alone or combined with enhanced diatomaceous earth (Probe-A® DE, 89.0% SiO 2 and 5% silica...
Article
Full-text available
A unique test chamber system, which enables experiments with plants under highly controlled environmental conditions, was used to examine the pollutant removal efficiency of plants. For this purpose, the removal of two different volatile organic compounds (VOC) (toluene, 2-ethylhexanol) from the air by aerial plant parts of two common indoor plant...
Article
Over the last decade, African indigenous leafy vegetables (AIVs) such as African nightshade (Solanum scabrum Mill.) have featured increasingly in both formal and informal markets in the peri-urban and urban centres of Africa, due to the increasing awareness of their nutritive and medicinal as well as expanding economic value. AIVs are rich in nutri...
Article
There is a dearth of knowledge on the available sources of botanical products for smallholder farmers in Africa and their bioactivity against stored-product pests. Many locally available plants across Africa exhibit both promising insecticidal, medicinal activity and are nutrient rich yet remain underutilized. Laboratory studies on toxicity of powd...
Article
Currently, consumer eating habits have shifted to an increasing demand for high quality, safe and healthy food products worldwide. In many African countries, specifically African indigenous leafy vegetables (AIVs) gained importance in this respect contributing to human diet by providing minerals, proteins, vitamins and health-promoting antioxidant...
Article
Full-text available
Growing environmental and sustainability concerns have driven continual modernization of horticultural practices, especially for urban farming. Controlled environment and soilless production methods are increasing in popularity because of their efficient resource use and intensive cropping capabilities. However, some popular substrates used for hyd...
Poster
In einem Verbund-Projekt zur Züchtung neuer Biomasseklone der Weide durch intra- und interspezifische Kreuzung wurden die Zuchtziele Biomasse, Rostpilzresistenz, Trockenstresstoleranz und Salicylatgehalt miteinander kombiniert. Bisher fanden als „Kurzumtriebs-Weiden“ stark wachsende Klone der Art Salix viminalis bzw. Hybriden mit Salix schwerinii V...
Poster
Vegetable amaranth (Amaranthus cruentus L.) is known for its high nutritional and health benefits, in addition it has the potential of creating employment opportunities especially for youth and women in Sub-Saharan Africa. However, the vegetable often suffer heavy postharvest losses (˃50%). Physical elicitors like UV-B are known to activate plant d...
Poster
In Europe, sweet cherries are popular but highly perishable fruit revealing high postharvest quality losses due to biotic impacts and, thus, have a short marketability. Applications of postharvest chemical (e.g. hydrogen peroxide, ethanol) and physical (e.g. heat, UV irradiation) treatments that influence ripening or inhibit microorganism decay has...
Poster
Full-text available
Changes in consumers’ lifestyle and the growing demand for convenience, nutritional and safe “ready-to-eat” fresh-cut fruit let the fresh-cut sector grow consistently. Cutting, however, inevitably induces wound responses including enhanced respiration, enzymatic browning of cut surfaces and tissue softening, and, thus, reduces shelf life. High resp...
Article
Full-text available
Farmers in Africa in general have repeatedly prioritized the urgent need for improved methods of storage pest control. Laboratory studies were evaluated on the toxicity of sublethal doses comprising of 25.0 × 103, 10.0 × 103, 20.0 × 103, 30.0 × 103, 40.0 × 103 and 50.0 × 103 ppm (wt/wt) paddy rice husk ash (PRHAP) and false yam Icacina oliviformis...
Article
Leaves of Moringa oleifera are used by tribes as biological cancer medicine. Scientific investigations with M. oleifera conducted so far have almost exclusively used total plant extracts. Studies on the activity of single compounds are missing. Therefore, the biological effects of the two main aromatic multi-glycosylated glucosinolates of M. oleife...