The fall armyworm (FAW, Spodoptera frugiperda) originates from the tropical and sub‐tropical regions of the Americas. Recently it was reported for the first time in Africa and has since spread rapidly across more than 30 countries in the continent. Chemical pesticides are being promoted and used for FAW management, but where application practices and/or the active ingredients are unsafe there is a need to make effective, low‐risk products available. Given that biopesticides such as microbials and microbial extracts, macrobials and semiochemicals are generally considered to be lower risk options for pest management, they are a promising avenue for exploration. When used in conjunction with good crop management, they can help to keep pest levels under control, reducing the need to apply other pesticides. This study provides a basis for designing interventions to make biopesticides more widely available for FAW control in Africa. It summarizes assessments of the registered pesticides and biopesticides for 30 countries, 11 in FAW's native range and 19 in Africa. The report identifies biopesticide active ingredients (AI) which are registered for use against FAW and provides an assessment of how appropriate these will be for use by smallholder farmers in Africa. For each biopesticide AI identified, detailed profiles were developed which covered the efficacy of the AI against FAW; the human health and environmental hazards associated with the AI; the agronomic sustainability of the AI; and whether or not the AI is practical for smallholder farmers to use. Using these data, a list of priority biopesticides for which follow‐up action is recommended was compiled. Fifty biopesticide AI were identified, which have been registered in one or more of the 30 countries for FAW management. Twenty‐three of these are recommended for follow‐up, for example field trials or bioassays.
Background: Although Kenya has a relatively high number of registered biopesticide products, little is known about biopesticide use by smallholders. This paper documents farmers' current use and perception of chemical pesticides and biopesticides, their willingness to pay for biopesticides, and the key challenges to biopesticide uptake. Results: A survey found that chemical pesticides are used widely by smallholders despite awareness of the risks to human health and the environment. Almost half of respondents showed awareness of biopesticides, but current use in the survey localities was low (10%). Key reasons for the low use of biopesticides by smallholders in this study are: perceptions of effectiveness, primarily speed of action and spectrum of activity, availability and affordability. Smallholders who used biopesticides cited effectiveness, recommendation by advisory services and perception of safety as key reasons for their choice. Although farmers viewed both pesticides and biopesticides as costly, they invested in the former due to their perceived effectiveness. Average willingness to pay, above current chemical pesticide expenditures per cropping season was 9.6% (US$5.7). Willingness to pay differed significantly between counties, and was higher among farmers with more education or greater awareness of the health risks associated with pesticide use. Conclusion: This study confirms the low use of biopesticide products in the survey areas, alongside high use of conventional chemical pesticides. In order to promote greater uptake of biopesticides, addressing farmers' awareness and their perceptions of effectiveness is important, as well as increasing the knowledge of those providing advice and ensuring registered products are available locally at competitive prices.
A symbiotic bacterium, strain IMI 397775T, was isolated from the insect-pathogenic nematode Steinernema australe. On the basis of 16S rRNA gene sequence similarity, this bacterial isolate was shown to belong to the genus Xenorhabdus , in agreement with the genus of its nematode host. The accurate phylogenetic position of this new isolate was defined using a multigene approach and showed that isolate IMI 397775T shares a common ancestor with Xenorhabdus doucetiae FRM16T and Xenorhabdus romanii PR06-AT, the symbiotic bacteria associated with Steinernema diaprepesi and Steinernema puertoricense, respectively. The nucleotide identity (less than 97 %) between isolate IMI 397775T, X. doucetiae FRM16T and X. romanii PR06-AT calculated for the concatenated sequences of five gene fragments encompassing 4275 nt, several phenotypic traits and the difference between the upper temperatures that limit growth of these three bacteria allowed genetic and phenotypic differentiation of isolate IMI 397775T from the two closely related species. Strain IMI 397775T therefore represents a novel species, for which the name Xenorhabdus magdalenensis sp. nov. is proposed, with the type strain IMI 397775T ( = DSM 24915T).
Five field surveys for indigenous entomopathogenic nematodes (EPNs) were conducted in 22 semi-natural and 17 small-holder farming habitats across 16 districts of different altitudes in the northern, eastern, southern and Kigali city provinces of Rwanda. In 2014, 216 mixed soil samples were collected and subsamples thereof baited with Galleria mellonella or Tenebrio molitor larvae. Five samples from five locations and habitats were positive for nematodes (2.8%). Nine nematode species/strains were isolated and five successfully maintained. DNA sequence comparisons and morphological examinations revealed Steinernema carpocapsae, Heterorhabditis bacteriophora, as well as two steinernematids and one heterorhabditid with no species designation. The isolates (strains) were named Steinernema sp. RW14-M-C2a-3, Steinernema sp. RW14-M-C2b-1, Steinernema carpocapsae RW14-G-R3a-2, H. bacteriophora RW14-N-C4a and Heterorhabditis sp. RW14-K-Ca. These are the first records of naturally occurring EPNs in Rwanda. It is also the first record of S. carpocapsae from Africa. Finding H. bacteriophora from tropical rather than temperate Africa was surprising. The found nematodes will serve as the basis for efficacy screening, and for mass production in a biocontrol agent factory at Rubona Research Centre of the Rwanda Agriculture Board with the ultimate aim of delivering effective, safe and environmentally benign pest control for soil-inhabiting pests. ARTICLE HISTORY
Fungi isolated from environmentally challenging habitats can have adaptations of potential value when developed as insect pest-controls. Fungal isolates collected from Antarctica, Geomyces sp. I, Geomyces sp. II, Mortierella signyensis and M. alpina, were investigated for (i) growth characteristics at 0–35°C, (ii) spore production at 10 and 20°C, (iii) viability following exposure to freezing temperatures, and (iv) insecticidal activity against waxmoths (Galleria mellonella L.), houseflies (Musca domestica L.), mealworms (Tenebrio molitor L.) and black vine weevils (Otiorhynchus sulcatus Fabricius). All isolates showed growth between 5–20°C, with some showing growth outside this range. Geomyces isolates sporulated over a wider range of conditions than the Mortierella isolates. Spore germination at 10°C was higher for Geomyces sp. II when this isolate was produced at 10 compared to 20°C (greatest difference 74.6 vs 32.7%). All isolates grew, with the exception of M. alpina, following exposure to −20°C for 4 weeks. Insecticidal investigations showed M. alpina and M. signyensis caused significant mortality of waxmoth and housefly larvae via injection and soil inoculation, and M. alpina caused significant mortality of housefly larvae via baiting; the Geomyces isolates had little lethal effect.
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