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Ethanolic and aqueous extracts of selected medicinal plants from Cameroon and Ghana were assessed for their in vitro anthelmintic activity by using the bovine filarial parasite Onchocerca ochengi and the free living nematode Caenorhabditis elegans, a model organism for research on nematode parasites. Worms were incubated in the presence of different concentrations of extracts and inhibitory effects were monitored at different time points. Among the extracts used in this study, ethanolic extracts of Anogeissus leiocarpus, Khaya senegalensis, Euphorbia hirta and aqueous extracts from Annona senegalensis and Parquetina nigrescens affected the growth and survival of C. elegans and O. ochengi significantly. The mortality was concentration dependent with an LC50 ranging between 0.38 and 4.00 mg/ml for C. elegans (after 72 h) and between 0.08 and 0.55 mg/ml for O. ochengi after a 24 h incubation time. Preliminary phytochemical screenings on these extracts revealed the presence of flavonoids, alkaloids, saponins, carbohydrates and tannins in the extracts. Accordingly, application of A. leiocarpus, K. senegalensis, E. hirta and A. senegalensis extracts could provide alternatives in the control of helminthic infections.

This study is aimed at evaluating the proximate composition and functional and sensory characteristics of gari obtained from five cassava varieties (EN, AD, TMS92/0326, TMS96/1414, and IRAD4115). These cassavas were harvested during the dry season 12 months after planting (12MAP) and in the rainy season (15MAP). Results showed that the characteristics of gari varied significantly (p < 0.05) with the variety and the harvest period. Gari from EN cassava harvested at 12MAP had the highest total carbohydrates (78.07% dry weight), starch (61%), and proteins content, while gari from TMS 96/1414 variety (12MAP) had high amino acids (10.25 mg/g) and phenolic compounds (9.31 mg/g) content. The gari from IRAD4115 had the highest value of ash content (20.62 mg/g) at 12MAP. The soluble sugar content was high in the gari from cassava harvested at 12MAP while free cyanide reduced significantly in gari from cassava harvested at 12MAP. The water absorption capacity, swelling power, and bulk density were significantly (p < 0.05) high in the gari from EN cassava variety at 12MAP. Compared to commercial gari (3.30), gari from EN local cassava had the best overall acceptability (4.35) followed by those obtained from TMS92/0326 and TMS92/1414 varieties, respectively.

Pest management in most sub-Saharan subsistence agriculture involves mainly the use of botanicals that are either applied as powders, solvent extracts, ash or essential oils. Two hydrogenated monoterpenes (α-pinene and 3-carene) from Cupressus sempervirens were tested against Sitophilus zeamais in the laboratory to evaluate the contact and fumigation effects on the mortality of adult and immature weevils, progeny production, and grain damage. Contact toxicity of the terpenes was investigated at these concentrations: 0.08, 4, 8 and 12 ppm (terpene/maize), while fumigant action was studied at the following doses: 1, 2, 3, and 4 ppm. The results indicate that insecticidal effects were concentration-dependent since mortality increased with dosage and exposure periods. After a 14-day exposure period at the concentration of 12 ppm of α-pinene and 3-carene/grain, more than 98% mortality of the mature weevils was observed at concentrations of 4.1333 and 1.642 ppm respectively and progeny production was reduced by 98% and 100%, respectively. When α-pinene and 3-carene were applied as fumigants, LC50s (lethal concentrations that generate 50% mortality) of 1.402 and 0.610 ppm were obtained after 24 h of exposure, respectively. At concentrations above 3 ppm, both monoterpenes acted as repellents to weevils and reduced grain damage by 80%. Both monoterpenes inhibited the development of immature stages of the weevil and reduced progeny by up to 94%. These compounds are very promising and effective and could be exploited as novel phytoinsecticides against the maize weevil.

Bacteria inhabiting the gut of insects provide many benefits to their hosts, such as aiding in food digestion, reproduction, and immunity, tissue homeostasis, adaptation to environment and resistance to pathogen and pesticides. The cowpea beetle, Callosobruchus maculatus , is a serious cosmopolitan pest of pulses. This beetle has lent itself as a guinea pig for several ecological studies. It harbors a consortium of bacterial communities in its gut, but the evidence for their role in its physiology is fragmentary. In this work, we hypothesized that gut microbiota mediates C . maculatus resistance to dichlorvos (DDVP or O , O -dimethyl O -2,2-dichlorovinylphosphate) and represent the target of Lippia adoensis (Gambian Tea Bush) essential oil (EO). Symbiotic and aposymbiotic beetles were exposed to artificial cowpea seeds earlier treated with DDVP or EO. Adult mortality and changes in gut bacterial community composition and abundance were examined at F 1 and F 5 generations. The susceptibility of experimental beetles to DDVP was significantly affected by their symbiotic status. The adult mortality decreased across generations in DDVP treatments, and remained significantly higher in aposymbiotic groups. In EO treatments, the mortality was consistent irrespective of symbiotic status and experimental generations. When compared to DDVP and the Control, EO treatments had significantly lower bacterial richness and diversity, as well as lower abundance of Proteobacteria, Firmicutes, and Bacteroidetes. These results support our hypothesis and describe the responses of gut microbial communities to pesticide treatments. This could be of interest for developing new management strategies of this pest.