Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Cameroon: case study on its distribution, damage, pesticide use, genetic differentiation and host plants

Open Access JournalMaize farmers in sub-Saharan Africa recently experienced unusual damage in their farms, attributed to the fall armyworm (FAW) Spodoptera frugiperda (J. E. Smith). This pest was first recorded in Africa in 2016, but detailed information on its distribution and damage and farmer's response in invaded areas are largely lacking. In this study, we determined FAW distribution, genetic diversity, host plants, crop damage, and farmers' responses. S. frugiperda was recorded in the 10 regions of Cameroon. Average percentage of infested plants and damage severity (on a scale of 1 to 5) were lowest-20.7 ± 7.4% and 2.1 ± 0.1 respectively-in the Sahelian regions and greatest-69.0 ± 4.3% and 3.1 ± 0.1 respectively-in the Western Highlands. Altitude did not influence FAW incidence and severity and its larvae infrequently co-occurred with maize stemborers on the same plants, suggesting possible direct and/or indirect competition between the two groups of maize pests. In response to this new threat to maize production, farmers have opted for the application of synthetic pesticides. Although our experiments were not designed to determine pesticide efficacy, as parameters such as time since application were not considered, our observations suggest lack of a drastic effect on S. frugiperda infestations on maize. There were two haplotypes of FAW co-occurring in Cameroon corresponding to the rice and corn strains and separated by 1.7% sequence divergence, which does not support the existence of cryptic species. S. frugiperda larvae were also recorded on Sorghum bicolor (L.) Moench (10.6%), Solanum tuberosum L. (2.8%), Ipomoea batatas (L.) Lam. (1.9%), Saccharum officinarum L (0.8%), Phaseolus vulgaris L. (0.4%) and Gossypium hirsutum L. (1.9%). This study show that two strains are present in all agroecological zones in Cameroon, and probably in neighboring countries of central Africa sharing the same agroecologies. Management options should therefore consider the use of specific natural enemies and an informed decision of intervention based on strain capture and damage threshold, to avoid pesticide resistance that may arise from inadequate use of chemicals. Further studies should also be undertaken to assess the response of the two S. frugiperda strains to biopesticides and botanical insecticides

Quest for a potent antimalarial drug lead: synthesis and evaluation of 6,7-dimethoxyquinazoline-2,4-diamines

Quinazolines have long been known to exert varied pharmacologic activities that make them suitable for use in treating hypertension, viral infections, tumors, and malaria. Since 2014, we have synthesized approximately 150 different 6,7-dimethoxyquinazoline-2,4-diamines and evaluated their antimalarial activity via structure-activity relationship studies. Here, we summarize the results and report the discovery of 6,7-dimethoxy-N(4)-(1-phenylethyl)-2-(pyrrolidin-1-yl)quinazolin-4-amine (20, SSJ-717), which exhibits high antimalarial activity as a promising antimalarial drug lead

Exploring the knowledge and awareness of diabetes mellitus among inhabitants of Ho municipality in Ghana: A cross-sectional study

One of the fast-growing major non-communicable diseases (NCD) that poses a danger to global public health is Diabetes mellitus (DM). Trends in  the incidence of DM indicate a disproportionate increase in developing countries due to current rapid demographic transitions from traditional to  more westernized and urbanized lifestyles. Knowledge of DM is vital for curbing or control. The objectives of this study were to evaluate the level of  knowledge and awareness of DM among the Ho municipality general population, identify areas of deficiency for targeted health education efforts,  and identify respondent characteristics that may be associated with knowledge of diabetes. A survey involving 132 respondents (age over 18 years)  was conducted in the Ho municipality of the Volta region of Ghana. A 42-item pre-tested questionnaire was administered to participants to evaluate  general and specific knowledge and awareness of DM. The Pairwise Multiple Comparison and Fisher’s Exact tests were used to test the hypotheses  and associations between the respondents’ knowledge level and groups respectively. Of the 132 respondents, 22% were in the age range of 40-46  years; 72.7% were female. Mean over all diabetes knowledge composite score was poor: 32.99% (CI; 27.5, 38.5). Respondents performed best in the  symptoms section: mean score was 36.247% (CI; 29.0, 43.4); and worst in the section on complications: mean score was 30.909% (CI; 23.6, 38.2). In  multiple linear regression analyses, education level, older age, own self having diabetes, and having a family member/relative/friend with diabetes  were significantly associated with knowledge of diabetes. Knowledge of diabetes among the inhabitants of Ho municipality respondents was  interpreted as being inadequate 32.99% (CI; 27.5, 38.5). Some deficient portions and factors associated with knowledge of diabetes were identified.  Relevant information for targeted health education programs in Ghana and beyond may be considered as one of such benefits of these findings.  &nbsp

Tephritid fruit fly species composition, seasonality, and fruit infestations in two central African agro-ecological zones

Open Access Journal; Published online: 13 Nov 2022Bactrocera dorsalis and several Africa-native Ceratitis species are serious constraints to fruit production in sub-Saharan Africa. A long-term trapping and fruit collection study was conducted (2011–2016) in two contrasting agro-ecological zones (AEZs) of Cameroon to determine fruit fly species composition, seasonality, attraction to various lures and baits, and fruit infestation levels. Ten tephritid species from genera Bactrocera, Ceratitis, Dacus, and Perilampsis were captured in traps. Bactrocera dorsalis was the most dominant of the trapped species and persisted throughout the year, with peak populations in May–June. Ceratitis spp. were less abundant than B. dorsalis, with Ceratitis anonae dominating in the western highland zone and Ceratitis cosyra in the humid forest zone. Methyl eugenol and terpinyl acetate captured more B. dorsalis and Ceratitis spp., respectively than Torula yeast. The latter was the most effective food bait on all tephritid species compared with Bio- Lure and Mazoferm. Bactrocera dorsalis was the dominant species emerging from incubated fruits, particularly mango, guava, and wild mango. Four plant species—I. wombolu, Dacryodes edulis, Voacanga Africana and Trichoscypha abut—were new host records for B. dorsalis. This study is the first long-duration and comprehensive assessment of frugivorous tephritid species composition, fruit infestations, and seasonality in Central Africa

Plantain hybrids for the humid forest agroecology of Central Africa – diseases and pests load, fruit yield and farmers perception

Open Access Journal; Published online: 01 Nov 2022Plantain is one of the major staples contributing to food security and income generation in West and Central Africa. Local cultivars in Cameroon are susceptible to pests and diseases causing severe losses in plantain production. This study aimed at evaluating the agronomic performance and producer’s perception of plantain hybrids in the humid forest of Cameroon. Field trials were established in a completely randomized block design with eight genotypes and three replicates. Data on pest and disease as well as farmer perception were collected over two growing cycles. These genotypes included seven improved and one local genotype (check). Improved genotypes were highly tolerant to the Black Sigatoka disease compared to local plantain. While root necrosis index was above 50% in local varieties, indices below 25% were recorded in hybrids. Weevil severity in local was higher (55.0 ± 5.2%) compared to 21.0 ± 4.6% to 28.5 ± 3.2% in improved plantains. Average bunch weight was higher for FHIA 21 with 17.9 ± 0.7 kg in the first and 19.7 ± 0.3 kg for the second cycle, while those of the local Ebang were 9.6 ± 0.5 kg and 12.8 ± 0.9 kg, respectively. FHIA 21 and CRBP 568 were the preferred varieties by farmers (68.8% and 56.3% acceptance) from an agronomic perspective. The consumers’ preferences for all the genotypes varied with types of cooking. The implications of these findings for adoption by farmers and consumers as well as for the promotion of the plantain sector in central Africa are discussed

The role of the disulfide bond in the interaction of islet amyloid polypeptide with membranes

Human islet amyloid polypeptide (hIAPP) forms amyloid fibrils in pancreatic islets of patients with type 2 diabetes mellitus. It has been suggested that the N-terminal part, which contains a conserved intramolecular disulfide bond between residues 2 and 7, interacts with membranes, ultimately leading to membrane damage and β-cell death. Here, we used variants of the hIAPP1–19 fragment and model membranes of phosphatidylcholine and phosphatidylserine (7:3, molar ratio) to examine the role of this disulfide in membrane interactions. We found that the disulfide bond has a minor effect on membrane insertion properties and peptide conformational behavior, as studied by monolayer techniques, 2H NMR, ThT-fluorescence, membrane leakage, and CD spectroscopy. The results suggest that the disulfide bond does not play a significant role in hIAPP–membrane interactions. Hence, the fact that this bond is conserved is most likely related exclusively to the biological activity of IAPP as a hormone

Strain induced martensitic transformation at high strain rate in two austenitic stainless steels

Two grades of unstable austenitic stainless steels, AISI 301LN and 201 were tested under uniaxial tension over a wide temperature range [−150°C; 150°C] and a large strain rate range [3.10−4 s−1; 200 s−1]. A special device was designed to run interrupted tests at high strain rates [50 s−1 & 200 s−1]. The γ → α’ phase transformation was characterized by magnetic measurements. The strain-induced phase transformations are different in these materials. Grade 301LN transformation sequence appears essentially to be γ → α’ whereas grade 201 sequence is γ → ε → α’. The nucleation of ε martensite is promoted by high strain rate, as shown by TEM observations. It is demonstrated that at high strain rates (≈ 50 s−1) the kinetics of the martensite transformation is largely reduced due to adiabatic heating. It is also shown that it is possible to account for the large reduction in the amount of strain-induced α’ martensite by taking into account the adiabatic effect. However, an accelerating effect of high strain rates is found when the materials are tested at an initial temperature close to Md. This observation is discussed in the light of the effect of strain rate on γ → ε transformation and, more generally, on planar deformation modes