Maize 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.

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Maize is cultivated worldwide and used as food and for fuel production. It is usually attacked and destroyed during storage by Sitophilus zeamais. With inaccessibility to synthetic pesticides, farmers are left with the choice of using locally available plant based pesticides. For this reason, we tested the insecticidal potentials of essential oils (EOs) of Chenopodium ambrosioides and Cupressus sempervirens and their binary combinations against S. zeamais on stored maize. Mortality, progeny inhibition, repellence and damage were tested. Pesticide characteristics of both essential oils were dose-dependent, 200 μL/kg of all the combinations caused at least 80% mortality within 14 days of storage while the 50:50 combination completely inhibited progeny production. Moreover, 8 μL of all the EO were repellent to the weevils. The 50:50 binary combination was the most active in all the tests carried out. Pesticidal interactions between the oils in combination were mostly additive and synergistic. There was also a good control of insect population increase and grain damage after six months of storage. Therefore both EOs can be recommended for the control of S. zeamais.

Cassava is a key food security crop in Central Africa, but its production depends largely on the use of local farmers’ varieties characterized by inherently low yield which is compounded by generally high susceptibility to various growth and yield-limiting pests and diseases. Improved cassava genotypes have demonstrated the potential to substantially improve cassava’s contribution to food security and the development of the cassava industry and the improvement of nutrition status elsewhere in Western Africa. Eleven improved cassava genotypes were compared with a local landrace (LMR) used as a check under field conditions over two years in eight locations, grouped in four agro-ecologies in Cameroon. Pest and disease abundance/incidence and damage severity were evaluated. At harvest, root yield and carotenoid content were measured. Best linear unbiased predictors showed the lowest breeding value for LMR with the cassava mosaic virus disease (+ 66.40 ± 2.42) compared with 1.00 ± 0.02% for the most susceptible improved genotype. Two genotypes (I010040-27 and I011797) stood out for having higher predicted fresh root yield means which were at least 16 times greater compared with LMR. Predicted total carotenoid content was the highest (+ 5.04 ± 0.17) for improved genotype I070593 compared with LMR which showed the lowest (− 3.90 ± 0.06%) and could contribute to the alleviation of vitamin A deficiency from cassava-based food systems. Diffusion of high-yielding and nutritious genotypes could alleviate food and nutritional security in Central Africa.

Article HistoryIn order to evaluate cassava roots yield of two varieties at three harvesting dates and assess the effect of harvesting date on physico-chemical composition of roots and quality of gari and baton de manioc, a study was done. Cassava roots of a popular variety (local white) and the improved variety 8034 were harvested in small holder farmers' fields in the mono-modal humid forest zone and the bimodal humid forest zone of Cameroon. At harvest, the yield was evaluated, the physico-chemical composition of roots evaluated and a sensory test carried out on gari and baton de manioc after processing. Results showed that harvesting date has an effect on the cassava roots yield, for both local white and variety 8034. Cassava yield varied according to agro-ecological zones, with higher yield in the mono-modal humid forest zone than the bimodal humid forest zone. The nutrient content in cassava root varied with the variety and age of roots. There was an increase with the age of roots for K, P and dry matter content for the variety 8034. With the local white variety, there was an increase in total N and dry matter content. In contrary, there was a gradual decrease of percentage Mg, K, Na with the age of cassava roots for the variety 8034.Baton de manioc obtained from variety 8034 at 10-12 months and gari obtained from same variety were scored the highest global quality. Contribution/Originality:This study is one of very few studies which have investigated the right harvesting time and the best cassava variety to be used to obtain good cassava based-products.