Papers by Christian Ulrichs
Anzeiger für Schädlingskunde, Oct 1, 2001
Field experiments with the synthetic insecticides, Methomyl and Carbaryl, alone and in combinatio... more Field experiments with the synthetic insecticides, Methomyl and Carbaryl, alone and in combination with the biological control agents, Bacillus thuringiensis (Bt) and Trichogramma evanescens, were conducted to control pests in yardlong beans, Vigna sesquipedalis, during the dry season 1998/1999. The experimental area was located at the Central Luzon State University in the province of Nueva Ecija on the Philippine main island Luzon. Carbaryl was applied against bean flies 5 days after plant emergence. Methomyl was sprayed against pod sucking insects and the bean podborer, Maruca vitrata, 45 days after plant emergence. The biological control agents were applied with the beginning of the flowering stage of V. sesquipedalis, when plants were first attacked by M. vitrata. Major insect pests on V. sesquipedalis were cowpea aphid (Aphis craccivora), leafminer (Liriomyza sp.), and bean podborer (M. vitrata). Both, Bt and T. evanescens had no significant impact on yield. M. vitrata eggs, exposed for 48 hours in the fields to augmented T. evanescens, were used to measure field efficacy of the parasitoid. Highest parasitism rate was 13.3 %, thus, generally low. Highest yield was obtained from plots treated with both synthetic insecticides. No significant difference in fresh pod yield was observed when, in addition to the synthetic insecticides, Bt and/or T. evanescens was applied. However, all treatments significantly out-yielded the untreated control.
Insects
The growth and nutritional profile of the black soldier fly larvae (BSFL) is usually investigated... more The growth and nutritional profile of the black soldier fly larvae (BSFL) is usually investigated and compared when the larvae feed on substrates that differ in the chemical composition as well as physical properties. This study compares BSFL growth on substrates that differ primarily in physical properties. This was achieved by using various fibres in the substrates. In the first experiment, two substrates with 20% or 14% chicken feed were mixed with three fibres (cellulose, lignocellulose, or straw). In the second experiment, the growth of BSFL was compared with a 17% chicken feed substrate that additionally contained straw with different particle sizes. We show that the substrate texture properties values did not influence the BSFL growth, but the bulk density of the fibre component did. The substrate mixed with cellulose led to higher larvae growth over time in comparison to substrates with higher bulk density fibres. BSFL grown on the substrate mixed with cellulose reached thei...
Insects
The proper treatment of cannabis agricultural wastes can reduce the environmental impact of its c... more The proper treatment of cannabis agricultural wastes can reduce the environmental impact of its cultivation and generate valuable products. This study aimed to test the potential of cannabis agricultural wastes as a substrate for the rearing of black soldier fly larvae (BSFL) and yellow mealworms (MW). In the case of BSFL, replacing the fibre component (straw) in the substrate with the hemp waste can increase the nutritional value of the substrate and led to bigger larvae. The bigger larvae had lower P and Mg, and higher Fe and Ca. Crude protein also varied based on the size of larvae and/or the content of protein in the initial substrate, which was boosted by replacing straw with hemp material. No other cannabinoids than cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), and cannabidiol (CBD) were found in significant amounts in the larvae. In the case of MW, the larvae grew less on the hemp material in comparison to wheat bran. Replacing wheat bran with the hemp material led t...
Fifth African Higher Education Week and RUFORUM Biennial Conference 2016, "Linking agricultural universities with civil society, the private sector, governments and other stakeholders in support of agricultural development in Africa, Cape Town", South Africa, 17-21 October 2016, 2016
Growing environmental and sustainability concerns have driven continual modernization of horticul... more 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 hydroponic cultivation, particularly rock wool, represent a large environmental burden in regard to their manufacture and disposal. Substrate-less hydroponic systems are effective in producing short cropping cycle plants such as lettuce or herbs, but less information is available for the production of plants with larger root-systems and longer cropping times. Here, we investigated the viability of a hybrid aeroponic/nutrient film technique (AP/NFT) system for the cultivation of greenhouse tomatoes (<em>Solanum lycopersicum </em>'Panovy'). The plants grown in the AP/NFT system had a more compact phenotype, accumulated more ...
Journal of Stored Products Research, 2022
The diet of many African rural and urban/peri-urban inhabitants is made up largely of indigenous ... more The diet of many African rural and urban/peri-urban inhabitants is made up largely of indigenous leafy vegetables (ALV) whose nutritional and medicinal value is well appreciated. Leafy amaranth is one of the most commonly eaten vegetables in Africa and Asia and contributes to improve food supply with essential proteins, minerals and antioxidative health promoting compounds [2]. However currently, the magnitude of postharvest losses of ALVs in Kenya can reach up to 50%. Applications of postharvest chemical (e.g. hydrogen peroxide) and physical (e.g. heat treatment, UV-C irradiation, MAP) treatments that retard ripening processes or inhibit microorganism decay has increased worldwide. So far, only limited studies have been conducted on African leafy vegetables [1]. UV-C has been used as a germicidal agent for water and surface disinfection including postharvest management of pathogens in fruits and vegetables due to its capacity to affect DNA of microorganisms. Low dosages of UV-C irr...
Journal of Plant Diseases and Protection, 2021
Three diatomaceous earths (DEs), InsectoSec®, Diatomeenerde Probe-A and Fossil Shield® 90.0, were... more 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. InsectoSec® was most effective towards adults, followed by Fossil Shield and finally Diatomeenerde. The highest dosages of the three DEs showed no difference in effectiveness on the 14th day, while InsectoSec® and Fossil Shield® were more effective than Diatomeenerde at the lower dosages. For InsectoSec®, the LD50 and LD90 values were 1.1% and 31.8% wt/wt, respectively, whereas Fossil Shield® recorded LD50 and LD90 of 1.0% wt/w and 13.2% wt/wt, respectively. Grain treated with InsectoSec, Fossil Shield and Diatomeenerde recorded less than 4%, 4% and 11% of C. maculatus progeny of the untreated control, respectively; dosage had no effect on t...
Moringa oleifera ist eine Baumart, welche ursprunglich aus dem SubHimalaya-Gebirge stammt, heute ... more Moringa oleifera ist eine Baumart, welche ursprunglich aus dem SubHimalaya-Gebirge stammt, heute in den Tropen und Subtropen jedoch weit verbreitet ist. Neben der Verwendung als Nahrungsmittel, wird M. oleifera als traditionelle Heilpflanze genutzt. Analysen verschiedener Autoren zeigten, dass wassrige, ethanolische sowie methanolische Blattextrakte ein antioxidatives, entzundungshemmendes sowie antikanzerogenes Potential besitzen. Ahnliche Effekte wurden auch nach einem erhohten Verzehr von Brassica-Arten, so z. B. Brassica oleracea var. italica, dem Brokkoli, beobachtet. Ein erhohter Verzehr dieser Gemuse wurde mit einem verminderten Risiko an Krebs zu erkranken in Verbindung gebracht. Das antikanzerogene Potential wird auf die in der Pflanze enthaltenen sekundaren Inhaltsstoffe, die Glucosinolate, zuruckgefuhrt. Da M. oleifera Glucosinolate mit einer seltenen Molekularstruktur besitzt und diese in der Pflanze in sehr hohen Konzentrationen vorliegen, wird vermutet, dass die beschr...
A first survey on plant viruses in African nightshade was carried out in small farms of Western K... more A first survey on plant viruses in African nightshade was carried out in small farms of Western Kenya. Food security and income generation of subsistence and semi-commercial farmers in African countries is one of the world’s key challenges. In this context, diverse abiotic and biotic stresses affect the productivity of protein-, fator vitamin-packed vegetables. Among biotic factors, viral diseases of vegetables gain considerable negative economic impact by compromising plant health, thereby affecting both yield and quality. In developing countries farming practices are usually smaller in scale and of lower input cost. Traditional growing of self-produced seeds, often due to inaccessibility of certified seed, and also growing of traditional, unimproved varieties increases the risk of infection. Virus disease management measures available are often poorly adapted to technological and educational standards of local agriculture. Concerted efforts to develop a sustainable integrated pest...
Julius-Kühn-Archiv, 2020
Zusammenfassung des Posters von BECK et al. (2019) Apium nodiflorum (Wassersellerie) ist eine ver... more Zusammenfassung des Posters von BECK et al. (2019) Apium nodiflorum (Wassersellerie) ist eine vergessene, gefährdete Wildpflanze und nah verwandt mit dem Kultursellerie. Diese Wildform hat großes genetisches Potential für die züchterische Bearbeitung und Verbesserung des Kulturselleries und als neue Kulturpflanze für die Allgemeinheit. Unser Ziel war die Inkulturnahme von Wassersellerie im Gewächshaus als neues vermarktungsfähiges Produkt. Da Wassersellerie an natürlichen Standorten in Gräben und Bächen vorkommt, wurden zwei fließende hydroponische Anbausysteme gewählt. Tochterpflanzen einer lokalen Wassersellerie-Population aus Knittelsheim wurden in Töpfen mit Substrat auf einer NFT-Rinne mit Leitungswasser und im Vergleich dazu in einem neuartigen NFT-Aeroponik-Hybridsystem mit einer Standardnährlösung für Tomaten (EC 2,0 ms cm-1 , pH 6,0) kultiviert. Nach drei Wochen Kulturzeit ergaben sich keine signifikanten Unterschiede in Bezug auf Frischgewicht und Pflanzenhöhe, jedoch waren bei den Pflanzen aus dem Hybridsystem die Trockensubstanzgehalte signifikant höher. Insbesondere konnten wir das Apig 1-Gen, dessen korrespondierendes Protein primär für das hohe allergene Potenzial des Kulturselleries ursächlich ist, in Wassersellerie nicht nachweisen. Bisher ist Wassersellerie für Verbraucher nicht erhältlich, aber aufgrund der vielen positiven Eigenschaften wie z. B. schnelles Wachstum, geringe Ansprüche und positiver gesundheitlicher Wirkung ist eine Inkulturnahme von Interesse.
Julius-Kühn-Archiv, 2018
To understand the diversity of stored grain insects in northwest China, we have fulfilled insect ... more To understand the diversity of stored grain insects in northwest China, we have fulfilled insect collection in 56 grain storage enterprises, 60 grain, oil and feed processing plants and 65 farmers situated in 26 cities of five provinces (Shaanxi, Gansu, Qinghai, Ningxia and Xinjiang) in northwest China from 2016 to 2017. After systematical identification, totally 83 species of stored grain insects have been found in this investigation, belonging to five orders, namely Class Insecta Order Zygentoma, Order Coleoptera, Order Lepidoptera and Order Hymenoptera, as well as Class Arachnida Order Chelonethida, in which Order Coleoptera owns 74 species in 22 families, Order Lepidoptera owns six species in four families, Order Zygentoma and Order Hymenoptera own one species in one family respectively, and Class Arachnida Order Chelonethida has one species in one family. After the statistics of four insect investigations in northwest China during 1955-2017, this paper has analyzed the results of four insect investigations and the representative stored grain insects in northwest China.
Plant-Environment Interactions, 2021
Onset of salinity induces the pH of the leaf apoplast of Pak choi transiently to increase over a ... more 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 underlying phenylpropanoids and for clarifying as to whether the apoplastic pH transient plays a role for such a putative effect, Pak choi plants were treated with 37.5 mM CaCl2 against a non‐stressed control. A third experimental group, where the leaf apoplast of plants treated with 37.5 mM CaCl2, was clamped in the acidic range by means of infiltration of 5 mM citric acid/sodium citrate (pH 3.6), enabled validation of pH‐dependent effects. Microscopy‐based live cell imaging was used to quantify leaf apoplastic pH in planta. Phenolics were quantified shortly after the formation of the leaf apoplastic pH transient by means of HPLC‐DAD‐ESI‐MS. Resu...
The Journal of Horticultural Science and Biotechnology, 2020
Tropospheric ozone is an important ambient atmospheric pollutant component in urban areas. Determ... more 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 (Brassica campestris L. ssp. chinensis). An experiment was conducted within an airtight bio-chamber for six consecutive days under 60 ppb ozone concentration. Different exposure duration conditions were 0 h/day, 1 h/day, and 4 h/day. The results showed no reaction of plant growth, but ozone exposure led to significant impacts in biochemical quality. The content of photopigments was not significantly impacted at 1 h/day, but significantly increased at the 4 h/day exposure condition. There was a significant decrease in the total glucosinolate (GLS) and total aliphatic GLS after the 4 h/day exposure condition; however, 4-Methylthiobutyl-GLS, total indole, and aromatic GLS were significantly increased. It appears that biochemical systems are more sensitive than the systems controlling plant growth, and this needs to be taken into account when implementing urban production sites for vegetables.
Scientia Horticulturae, 2019
Determining plant reactions to atmospheric pollutants is important in predicting and planning for... more 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 the role of ozone stress on early vegetative growth stage Pak-Choi (Brassica campestris L. ssp. chinensis). An experiment was conducted within airtight bio-chambers under 150 ppb ozone concentration with different exposure durations: control, 1 h/day and 4 h/day. The leaf area was not affected by ozone treatment, but the dry matter correlated negatively with increasing ozone exposure durations. In photopigments, the lutein, lycopene and chlorophylls were increased at 1 h/day exposure, however, total carotenoids and β-carotene were not affected. However, for the 4 h/day exposure condition, all photopigment contents were significantly decreased in comparison to the 1 h/day exposure. The total aliphatic and total glucosinolate (GLS) were significantly increased at 1 h/day exposure, and then significantly decreased at 4 h/day exposure. However, the total indole and aromatic GLS were significantly increased after 4 h/day exposure. Therefore, these results provide evidence about the impact of ozone stress on the specific secondary plant metabolites of Pak-Choi and this needs to be taken in account when selecting urban production sites for vegetables.
International Journal of Tropical Insect Science, 2017
Food losses caused by insects during postharvest storage are of paramount economic importance wor... more 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% SiO2 and 5% silica aerogel) to adult Sitophilus granarius, Tribolium castaneum and Acanthoscelides obtectus. Adult mortality was observed up to 7 days, while progeny production was recorded at 6–10 weeks. LD50 and LT50 values for adult test insects exposed to plant powders and DE, showed that A. obtectus was the most susceptible towards the botanicals (LD50 0.179% and 0.088% wt/wt for E. aromatica and M. oleifera, respectively), followed by S. granarius. Tribolium castaneum was most tolerant (LD50 1.42% wt/wt and 1.40% wt/wt for E. aromatica and M. oleifera, respectively). The combined mixture of plant powders and DE controlled the beetles faster compared to ...
Scientia Horticulturae, 2019
Food & function, Jan 9, 2016
Leaves of Moringa oleifera are used by tribes as biological cancer medicine. Scientific investiga... more 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. oleifera were investigated in the present study. The cytotoxic effects of M. oleifera glucosinolates were identified for HepG2 cells (NRU assay), for V79-MZ cells (HPRT assay, SCE assay), and for two Salmonella typhimurium strains (Ames test). Genotoxic effects of these glucosinolates were not observed (Ames test, HPRT assay, and SCE assay). Reporter gene assays revealed a significant increase in the ARE-dependent promoter activity of NQO1 and GPx2 indicating an activation of the Nrf2 pathway by M. oleifera glucosinolates. Since both enzymes can also be induced via activation of the AhR, plasmids containing promoters of both enzymes mutated in t...
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Papers by Christian Ulrichs