Biologische Bekämpfung des Maiskäfers Sitophilus zeamais (L.) (Coleoptera: Curculionidae) in Mais mit der Lagererzwespe Lariophagus distinguendus (Förster) (Hymenoptera: Pteromalidae) sowie der Reismotte Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) in Reis mit der Mehlmottenschlupfwespe Habrobracon hebetor (Say) (Hymenoptera: Braconidae)

Maize and rice constitute some of the most important cereals cultivated in the world, being used as staple food for people especially in Africa. The rice moth, Corcyra cephalonica, and the maize weevil, Sitophilus zeamais, are major pests of stored grains in the tropics. The use of parasitoids in biological pest control is already common in different agricultural and horticultural fields. At present, grain managers tend to look at alternatives to chemicals to control insects in stored grain. Lariophagus distinguendus (Förster) is a synovigenic, solitary larval and pupal ectoparasitoid of several beetle species that infest stored goods. The ability for long-range host finding of this parasitoid mediated by volatiles has been shown (Steidle & Schöller 1997). Habrobracon hebetor (Say) is a gregarious ectoparasitoid of many lepidopterous pests. This wasp occurs naturally in the stored grain ecosystem (Keever & al. 1985) where it attacks several pyralid moths, including the rice moth, Corcyra cephalonica. The present study was conducted to assess the host finding of the two parasitoids H. hebetor and L. distinguendus.Wenn Vorratsschädlinge gefüllte Säcke befallen ist eine Bekämpfung mit Hilfe durchgreifender Methoden wie z.B. Begasung oder der Einsatz von Kälte möglich. Die Anwendung dieser Verfahren ist aber technisch nicht immer realisierbar. Verschiedene parasitoide Hymenopteren werden zur biologischen Bekämpfung von Vorratsschädlingen eingesetzt. Diese Wespen dringen in der Regel nicht in Verpackungen ein. Säcke aus Jute besitzen jedoch eine Maschenweite, die das Eindringen von Nützlingen erlauben könnte. Um die Möglichkeit des Nützlingseinsatzes in Sacklägern zu prüfen, wurden folgende Untersuchungen durchgeführt: (1) Wirtsfindung von Habrobracon hebetor in gesacktem Langkornreis (5 kg-Säcke, Raupen von Corcyra cephalonica 4 cm tief im Reis) (2) Wirtsfindung von Lariophagus distinguendus in gesacktem Mais (5 kg-Säcke, Befall durch Sitophilus zeamais). Es wurde täglich auf eindringende L. distinguendus bzw. H. hebetor hin kontrolliert. Der tägliche Schlupf der Nachkommen der Wespen wurde dokumentiert. H. hebetor war nur zu einem sehr geringen Anteil in der Lage, in die Säcke einzudringen. 50% der eingesetzten L. distinguendus drangen in die Jutesäcke ein und verringerten den Populationsaufbau der Maiskäfer. Begleitende Untersuchungen in unverpacktem, geschüttetem Reis ergaben, dass H. hebetor mindestens 14 cm tief eindringt und Reismottenraupen parasitiert

Bioefficacy of enhanced diatomaceous earth and botanical powders on the mortality and progeny production of Acanthoscelides obtectus (Coleoptera: Chrysomelidae), Sitophilus granarius (Coleoptera: Dryophthoridae) and Tribolium castaneum (Coleoptera: Tenebrionidae) in stored grain cereals

This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.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 the plant powders alone. LT50 ranged from 55.7 h to 62.5 h for T. castaneum exposed to 1.0% M. oleifera and 1.0% DE, and 0.5% E. aromatica and 1.0% DE, respectively. Botanicals caused significant reduction of F1 adults compared to the control. Combined action of botanical insecticides with DE as a grain protectant in an integrated pest management approach is discussed.Peer Reviewe

Econometrics of Domestication of the African Palm Weevil (<em>Rhynchophorus phoenicis</em> F.) Production as Small-Scale Business in Ghana

A reconnaissance survey of the domestication of the African palm weevil (APW) (Rhynchophorus phoenicis), which produces the edible larvae that are cherished as a delicacy among many tribes in Ghana, was conducted. Out of a total number of 560 semi-trained farmers, 271 (48.39%) were actively engaged in R. phoenicis farming near their homes or gardens, while 289 (51.61%) were non-active. Economic viability analyses showed that the active farmers would break even and repay their loans of GH¢1000 when they produce 3020 larvae at unit selling price of GH¢0.33, within a period of 4 months and 7 days (17 weeks). In a year, a farmer would have three production cycles and generate a total revenue of GH¢3018.79, at average monthly production of 755 edible larvae, net cash availability of GH¢1448.79, and projected net profit of GH¢448.79 in the first year of production. The farmer would make more profit and become wealthy in business in subsequent years. The pilot scheme of palm weevil farming was viable and ameliorated poverty and malnutrition of rural farmers in Ghana

Evaluation of aflatoxin contamination of stored maize in the Brong-Ahafo region of Ghana: Poster

This study assessed the aflatoxin contamination and the presence of fungi in three maize varieties (Obatanpa, Abontem and Aburohemaa) stored using different storage methods namely storage in hermetic bags, woven polypropylene sacks and local crib in the Nkoranza-South district of the Brong-Ahafo region of Ghana. A factorial design arrangement was laid out in a randomized complete block design (RCBD). The isolation and identification of fungal pathogens associated with maize samples before and after storage were carried out on potato dextrose agar (PDA). Total flatoxin levels in the three maize varieties was determined by the use of enzyme-linked immunosorbent assay (ELISA) at 450 nm wavelength. Six fungi species were identified in the maize namely: Aspergillus flavus, Penicillium sp, Fusarium sp., Lasiodiplodia theobromae, Colletotrichum gleosporioides and Rhizopus. Before storage, Abontem variety recorded significantly higher (p &lt; 0.05) total aflatoxin levels (113.56 ppb) compared to Obatanpa (2.91 ppb) and Aburohemaa (2.96 ppb). Maize samples stored in the polypropylene sack established significantly higher (p &lt; 0.05) total aflatoxin levels of 82.9 ppb compared to hermetic bags (48.9 ppb) and local crib (48.9 ppb) after storage for six months. Aflatoxin levels under the interactive effect of variety and storage method was significant (p &lt; 0.05). Overall storage of maize in hermetic bags significantly reduced aflatoxin levels hence the need to encourage maize farmers and traders to adopt hermetic bag storage technology.This study assessed the aflatoxin contamination and the presence of fungi in three maize varieties (Obatanpa, Abontem and Aburohemaa) stored using different storage methods namely storage in hermetic bags, woven polypropylene sacks and local crib in the Nkoranza-South district of the Brong-Ahafo region of Ghana. A factorial design arrangement was laid out in a randomized complete block design (RCBD). The isolation and identification of fungal pathogens associated with maize samples before and after storage were carried out on potato dextrose agar (PDA). Total flatoxin levels in the three maize varieties was determined by the use of enzyme-linked immunosorbent assay (ELISA) at 450 nm wavelength. Six fungi species were identified in the maize namely: Aspergillus flavus, Penicillium sp, Fusarium sp., Lasiodiplodia theobromae, Colletotrichum gleosporioides and Rhizopus. Before storage, Abontem variety recorded significantly higher (p &lt; 0.05) total aflatoxin levels (113.56 ppb) compared to Obatanpa (2.91 ppb) and Aburohemaa (2.96 ppb). Maize samples stored in the polypropylene sack established significantly higher (p &lt; 0.05) total aflatoxin levels of 82.9 ppb compared to hermetic bags (48.9 ppb) and local crib (48.9 ppb) after storage for six months. Aflatoxin levels under the interactive effect of variety and storage method was significant (p &lt; 0.05). Overall storage of maize in hermetic bags significantly reduced aflatoxin levels hence the need to encourage maize farmers and traders to adopt hermetic bag storage technology

Effect of terroir on the glucosinolate content of Moringa oleifera grown in three agro-ecological zones of Ghana

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 sulfur) on the glucosinolate content in leaves of wild-grown Moringa oleifera from three agro-ecological zones in Ghana and selected M.oleifera accessions cultivated under semi-controlled field conditions. The results showed that climate did not significantly influence total glucosinolate content in leaves of both wild-grown and cultivated accessions of M.oleifera, while elevation significantly influenced the total glucosinolate content of wild-grown plants. Fertilization had no significant impact on the total glucosinolate content of the cultivated accessions. Furthermore, wild-collected M.oleifera leaves from the three agro-ecological zones did not reveal a significant difference in their total glucosinolate content. For the cultivated accessions of M.oleifera, the agro-ecological zone, harvest time, and accession and the interactions among these factors significantly influenced the total glucosinolate content. The results suggest that selecting suitable accessions, choosing suitable locations, and applying appropriate cultivation practices could contribute to optimizing the production of health-promoting Moringa plants with special emphasis on glucosinolate content

Complement activation in Ghanaian children with severe Plasmodium falciparum malaria

<p>Abstract</p> <p>Background</p> <p>Severe anaemia (SA), intravascular haemolysis (IVH) and respiratory distress (RD) are severe forms of <it>Plasmodium falciparum </it>malaria, with RD reported to be of prognostic importance in African children with malarial anaemia. Complement factors have been implicated in the mechanism leading to excess anaemia in acute <it>P. falciparum </it>infection.</p> <p>Methods</p> <p>The direct Coombs test (DCT) and flow cytometry were used to investigate the mean levels of RBC-bound complement fragments (C3d and C3bαβ) and the regulatory proteins [complement receptor 1 (CD35) and decay accelerating factor (CD55)] in children with discrete clinical forms of <it>P. falciparum </it>malaria. The relationship between the findings and clinical parameters including coma, haemoglobin (Hb) levels and RD were investigated.</p> <p>Results</p> <p>Of the 484 samples tested, 131(27%) were positive in DCT, out of which 115/131 (87.8%) were positive for C3d alone while 16/131 (12.2%) were positive for either IgG alone or both. 67.4% of the study population were below 5 years of age and DCT positivity was more common in this age group relative to children who were 5 years or older (Odds ratio, OR = 3.8; 95%CI, 2.2–6.7, p < 0.001). DCT correlated significantly with RD (β = -304, p = 0.006), but multiple regression analysis revealed that, Hb (β = -0.341, p = 0.012) and coma (β = -0.256, p = 0.034) were stronger predictors of RD than DCT (β = 0.228, p = 0.061). DCT was also not associated with IVH, p = 0.19, while spleen size was inversely correlated with Hb (r = -402, p = 0.001). Flow cytometry showed similar mean fluorescent intensity (MFI) values of CD35, CD55 and C3bαβ levels on the surfaces of RBC in patients and asymptomatic controls (AC). However, binding of C3bαβ correlated significantly with CD35 or CD55 (p < 0.001).</p> <p>Conclusion</p> <p>These results suggest that complement activation contributed to anaemia in acute childhood <it>P. falciparum </it>malaria, possibly through induction of erythrophagocytosis and haemolysis. In contrast to other studies, this study did not find association between levels of the complement regulatory proteins, CD35 and CD55 and malarial anaemia. These findings suggest that complement activation could also be involved in the pathogenesis of RD but larger studies are needed to confirm this finding.</p

Evaluation of different substrates on the life history parameters of African palm weevil, Rhynchophorous phoenicis (Coleoptera: Curculionidae) in Ghana

AbstractAfrican palm weevil (Rhynchophorus phoenicis) larvae are widely consumed in Ghana and most countries in Africa because of their high-quality protein and low greenhouse gas emissions than conventional livestock. However, the consumption of the larvae is hindered by the identification of viable agricultural by-products or artificial diets for production. To address this challenge, Rhynchophorus phoenicis was evaluated on three substrates, namely cassava, sugarcane, and palm yolk, to determine the fecundity and hatchability of eggs. Completely Randomized Design was used to assign substrates with four replications each. Overall, adults reared on palm yolk laid average of 76.2 eggs while the cassava and the sugarcane substrate recorded averages of 73.0 eggs and 63.3 eggs, respectively. This result exhibited a significant difference between the substrates. The egg hatchability of adults reared on cassava was comparable to those fed on a natural host (palm yolk). Cassava can be used as substitute for the production of adult African palm weevil

Potential of Hymenopteran larval and egg parasitoids to control stored-product beetle and moth infestation in jute bags

The control of stored-product moths in bagged commodities is difficult because the developmental stages of the moths are protected by the bagging material from control measures such as the application of contact insecticides. Studies were carried out to assess the ability of Hymenopteran parasitoids to locate their hosts inside jute bags in the laboratory. The ability of different parasitoids to penetrate jute bags containing rice was investigated in a controlled climate chamber. Few Habrobracon hebetor (Say) (Hymenoptera: Braconidae) passed through the jute material while a high percentage of Lariophagus distinguendus (Förster), Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae), Theocolax elegans (Westwood) (Hymenoptera: Pteromalidae) and Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) were able to enter the Petri-dishes. Significantly more L. distinguendus and T. elegans entered compared to H. hebetor. There was significant difference in the mean percentage parasitoids invading depending on species. Head capsules and/or thorax widths were measured in order to determine whether the opening in the jute material would be large enough for entry of the parasitoids. These morphometric data differed depending on parasitoid species and sex. The parasitoid Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae) did not enter the bags, but located host larvae inside the jute bags and parasitized rice moths Corcyra cephalonica larvae by stinging through the jute material. Venturia canescens significantly reduced the number of C. cephalonica adults emerging from the bagged rice; therefore, it could be released in storage rooms containing bagged rice for biological control of C. cephalonica. The use of parasitoids to suppress stored-product insect pests in bagged commodities could become a valuable supplement to the use of synthetic pesticides.Peer Reviewe