The fall armyworm (FAW), Spodoptera frugiperda; (J.E. Smith; Lepidoptera, Noctuidae), is a major threat to maize crop. Although several studies showed that intercropping maize with legumes and good fertilizing of maize can reduce the pest attacks, the synergistic effect of these two approaches was under-studied. The current study aims to assess the synergy between maize-pigeon pea intercropping and low fertilization on FAW larval infestation, maize plant growth, natural enemies, and grain yield. A field experiment was conducted at International Institute of Tropical Agriculture, Benin station in the district of Abomey-Calavi (6 degrees 24' N, 2 degrees 21' E) for this purpose. Fertilization treatments including three low doses of NPK: 150 kg NPK ha-1 , 150 kg NPK ha-1 + 25 kg ha-1 urea (N: 46 %), 150 kg NPK ha-1 + 50 kg ha-1 urea (N: 46 %), along with a no-fertilization control, were arranged in a complete randomized block design with three replicates. Results showed that applying low NPKS fertilization at 150 kg ha-1 to maize intercropped with Pigeon pea significantly reduced FAW larval density, leaf damage severity, induced the highest height and grain yields while increasing populations of parasitoids. These findings support integrated soil fertility management and demonstrate that companion plant with Pigeon pea can be an effective cultural control strategy for FAW. This method provides a sustainable alternative to synthetic insecticides, promoting environmentally friendly agricultural practices.

The fall armyworm (FAW), Spodoptera frugiperda, a major pest in maize production, was assessed for its temporal and spatial distribution in maize fields during both the dry and rainy seasons of 2021 and 2022 in two agroecological regions in Benin (zone 6 and 8). Zone 6 (AEZ 6) “called zone of terre de barre” (Southern and Central Benin) consisted of ferralitic soils, a Sudano-Guinean climate (two rainy seasons alternating with two dry seasons) with a rainfall ranging between 800 and 1400 mm of rainfall per year; while zone 8 (AEZ 8) called “fisheries region” (Southern Benin” is characterized by coastal gleysols and arenosols with a Sudano-Guinean climate and a rainfall of 900–1400 mm of rainfall per year. In this study, 30 and 50 maize plants were randomly sampled using a “W” pattern during the dry and rainy seasons, respectively. Larval density, larval infestation rates, and damage severity were monitored over time. Taylor’s power law and the mean crowding aggregation index were applied to evaluate the dispersion patterns of the larvae. The results indicate a higher larval infestation rate and larval density in AEZ 8 compared to AEZ 6 during the dry season. In the rainy season, while the percentage of damaged plants was higher in AZE 8, no significant differences in larval density between the two zones were observed. The dispersion analysis revealed moderate aggregation (aggregation index = 1.25) with a basic colony of 2.08 larvae, i.e., an average initial cluster of 2.08 larvae observed per plant, reflecting the aggregation oviposition behavior of FAW. This study provides valuable monitoring data on the FAW’s distribution, offering insights for further research on population dynamics and developing predictive models for integrated pest management strategies.

Purpose. This study aimed to examine the willingness to pay (WTP) of mango farmers for a new biopesticide to control fruit flies in western Burkina Faso. Methodology / approach. This study is based on the example of mango farmers in Western Burkina Faso, which is the largest mango-producing area in the country. This research used a multistage sampling technique, the first of which involved selecting two regions where mango production is predominant and where late varieties are highly susceptible to fruit fly attack. In the second stage, three provinces were reasonably selected: Kénédougou, Comoé, and Houet in the west of the country. To achieve this goal, a cross-sectional data were gathered from a sample of 341 mango growers. The contingent valuation method was applied and the Cragg Double-Hurdle model was used for analysis. Furthermore, primary data was obtained from respondents through interviews, and secondary data was obtained from relevant agencies. Results. The results indicate that 81.52 % of growers are willing to pay an average of FCFA 2,745 and 70.38 % of them proposed an average amount to be paid of FCFA 2,851 for a weekly treatment with the new biopesticide. Education, access to advisory services, knowledge of fruit flies, and organic production methods influence both growers’ decision to pay and the value of their WTP. Additionally, the willingness to pay for the new biopesticide is positively influenced by the farming area and the perception of the detrimental effects of chemical pesticides on human health and the environment, while the decision to adopt is positively influenced by the income generated from the production of mangos. Knowledge of WTP and its determinants will make it possible to put in place appropriate and effective mechanisms for disseminating information on the new biopesticides to improve fruit fly control and, in turn, farmers’ production and income. Originality / scientific novelty. Despite the threat posed by fruit flies to the mango industry, no studies in Burkina Faso have examined the willingness to pay for methods to control these pests. The novelty of this research is in its application of the Cragg Double-Hurdle analytical model in an ex-ante setting for a new biopesticide. This is the first time that the price farmers are willing to pay for a new fruit fly control method and the factors that determine its use have been scientifically assessed before it is introduced to the market in Burkina Faso. Policymakers and other stakeholders will be able to use the analytical results to promote the new biopesticide for widespread use, as opposed to conventional control approaches. Practical value / implications. To effectively control fruit flies, it is necessary for decision makers to work closely with the private sector to make the yeast waste-based biopesticide for fruit fly control affordable by creating incentives for its multiplication and distribution. Extension services should also be involved in promoting this technology to growers. Finally, awareness-raising campaigns for growers on fruit fly damage and the biopesticide for successful collective control should be stepped up.

Fopius arisanus (Sonan) is an ovo-pupal parasitoid used as biocontrol agent against the oriental fruit fly Bactrocera dorsalis (Hendel). The effectiveness of this parasitoid in the natural agro-ecosystems depends partly on the quality of its mass rearing system. Preparation of the imported hydrolysate yeast-based diet usually results in high costs as the hydrolysate yeast is very expensive. We therefore assessed some local protein-rich products including powders of moringa, cassava leaves, and soybean flour as substitutes to the expensive imported hydrolysate yeast. The results revealed that eggs hatchability of B. dorsalis on moringa diet was higher while the adult emergence rate was lower. Cassava leaves-based diet did not differ from the deactivated hydrolysate yeast diet in eggs hatchability, pupal recovery, and emergence rate of adult B. dorsalis. However, F. arisanus- parasitized B. dorsalis egg hatchability on moringa leaves- and cassava leaves-based diets were higher than on the other diets. Pupal recovery from cassava leaves-, papaya- and soybean flour-based diets were lower than from the control. Parameters such as larval duration, larval survival rate and sex ratio did not differ significantly between treatments for any of the two insect species. The emergence rate of F. arisanus did not differ from one treatment to another. The best cost-effective local protein-based diet, available for local use and which offered performances close to those of the control diet, was the cassava leaves-based diet.

Pupation is one of the most crucial but vulnerable stages of development for Lepidoptera. It most often takes place in the soil, an ecosystem where biotic, abiotic and human-induced factors can affect this inherent process which is essential for population growth. The present study aimed to evaluate, in laboratory and in the field, the influence of three tropical soil types and pupal burial depths in these soils on pupation and emergence of Spodoptera frugiperda (fall armyworm), an invasive, highly voracious pest of maize in Africa. Trials were carried out on ferralitic, ferruginous and hydromorphic soils at depths of 0 - 10 cm, both in the laboratory with a moisture content of approximately 30%, and also on farms in four maize plots for each soil type. The results indicated that ferralitic and ferruginous soils were relatively more favourable for pupation, which occurred at depths of 1.8 and 1.9 cm with pupation rates of 97 -100 and 33 -40% respectively in the laboratory and in the field and emergence rates of 95 and 77 -84% respectively in the laboratory and in the field. Pupation occurred in the hydromorphic soil at a depth of 1.7 cm with pupation rates of 85 and 19% in the laboratory and in the field respectively, and emergence rates of 75 and 41% in the laboratory and in the field respectively. Pupal burial at 2 cm in ferralitic or ferruginous soils and at 9 cm in hydromorphic soil did not allow the emergence of moths. This study provides an effective tool for S. frugiperda control during its pupal stage.

The African weaver ant Oecophylla longinoda builds woven leaf nests inside tree canopies and is a major conservation biocontrol agent in sub‐Saharan Africa. Weaver ant colonies provide well‐protected and resource‐rich environments for many associated trophobionts, thereby boosting their establishment on host plants. There is very little published literature on O. longinoda, their hosts plants and their associated trophobionts in West Africa. These tri‐trophic interactions were studied over a period of four consecutive years (2010–2013) from south to north Benin. Our fieldwork revealed that all O. longinoda colonies were consistently associated with trophobionts. Oecophylla longinoda nests were recorded on 82 plant species belonging to 30 families, with 35 associated trophobiont species representing 11 families. Among cultivated plants, Mangifera indica was the most common species hosting O. longinoda, while Sarcocephalus latifolius the most frequent native one. Among trophobionts, Parasaissetia nigra, Udinia catori, Udinia farquharsoni (Coccidae) and Stictococcus sjostedti (Stictococcidae) were the most common hemipterans associated with O. longinoda. We identified a wide range of host plants that could be preserved (or planted) to promote the establishment of weaver ants to control different insect pests in fruit plantations in sub‐Saharan Africa. When planted around fruit plantations with their nests and tended hemipterans, these host plants could facilitate biocontrol of mango fruit flies (Tephritidae) and cashew bugs (Coreidae, Miridae), by O. longinoda in the fruit plantations.

Weaver ant (Oecophylla longinonda) used in biological control of pest, is said to improve the organoleptic quality of protected fruits. This study aims at bringing out stakeholders’ perception of weaver ants effect on mango quality. A survey was performed in Parakou (Benin), with stakeholders to assess their perception of mango quality and their opinion about weaver ant’s effect on mango quality. Then, the taste and the appearance (performed on unwashed and washed fruits) of three categories of mango: Control mango CM (Mango without ants), ants mango without scale insect (AM) and ants mango with scale insects (AMS) were evaluated by 25 panelists. Survey showed that maturity, appearance, size, non-infestation and firmness were the main criteria used by stakeholders to assess mango quality. Differences between protected and non-protected mango were based mainly on taste, appearance and non-infestation (68.8%; 48.4%; 31.3% of respondents, respectively). Most respondents (88.6%), who used taste to differentiate protected mango from non-protected mango, declared that the former is sweeter than the latter. Some respondents (35.5%) negatively pointed out the presence of scale insects and / or ants marks on the peel of protected mango. All respondents stated that protected mango is non-infested by pest. Similarly, sensory test showed that AMS scored the highest grade (4.5) followed by AM (3.9) and CM (2.8) for the taste (for washed fruits), registered the highest score (3.8) ahead AM (3.2) and CM (2.7). This investigation showed that weaver ants improve mango, taste and appearance. Mango quality changes due to the presence of weaver ants should be investigated. Key words: Oecophylla longinoda, biological control, survey, criteria, Parakou, organoleptic quality.

Weaver ants, Oecophylla spp., are known to positively affect cashew, Anacardium occidentale L., raw nut yield, but their effects on the kernels have not been reported. We compared nut size and the proportion of marketable kernels between raw nuts collected from trees with and without ants. Raw nuts collected from trees with weaver ants were 2.9% larger than nuts from control trees (i.e., without weaver ants), leading to 14% higher proportion of marketable kernels. On trees with ants, the kernel: raw nut ratio from nuts damaged by formic acid was 4.8% lower compared with nondamaged nuts from the same trees. Weaver ants provided three benefits to cashew production by increasing yields, yielding larger nuts, and by producing greater proportions of marketable kernel mass.

We interviewed half of the mango-growers in northern Benin, including 15 farmers involved in a regional fruit fly project, and held focus group discussions with women fruit-pickers. They were asked about pest management and their knowledge of a weaver ant, Oecophylla longinoda. All considered low yields due to fruit flies to be the principal constraint upon mango production, estimating economic losses to be between 20 and 45%. None could recognize damage during the first 2 days after fruit fly egg deposition. On-farm research persuaded farmers to stop using insecticides and it also changed negative perceptions of Oecophylla. Over 80% of the farmers involved in on-farm research, compared to 25% of those not involved, reported Oecophylla to be beneficial. All fruit-pickers knew that ants protected mango from fruit flies, with 60% attributing better mango quality in terms of appearance, shelf-life and sweetness to the presence of Oecophylla. Nevertheless, 40% of the pickers still considered weaver ants a nuisance pest during harvest. Ways of reducing this nuisance need to be developed for Oecophylla to gain wider acceptance by mango-growers.

The bioefficacy of various plant extracts, namely Azadimchta indica A . Juss, Khaya senegalensis Desrousseaux (A. Jussieu) and Hyptis suavuolens (L.) Poit, either alone or in combination with half the recommended dose of synthetic pesticides, was studied with farmers to find a more sustainable strategy for the management of bollworms in cotton. A number of treatments were farmer innovations. The treatments were compared six times during the season to the application of the fully recommended dose of synthetic pesticides and to a control with no pesticide application. Applications of either the fully recommended dose of the synthetic pesticides or the combinations with a neem seed extract (6 kg/ha) were most effective in reducing bollworm incidence and damage. Both the treatments gave the highest yields of cottonseed, the latter being the most cost-effective. All the pesticides used, except neem alone, had a toxic effect on bollworm predators. This study has increased farmers’ confidence in endogenous technology. The researcher’s interaction among the local learning group members, who conducted the experiments, facilitated the introduction of a cost-effective alternative to the standard fulldose synthetic pesticide recommendation.

Cotton production constraints in Benin as perceived by farmers were studied from May to July 2003. The knowledge, perceptions and practices of farmers growing cotton under different pest management regimes were analysed. The methods used were open and semi-structured interviews with groups and individuals, as well as participatory exercises (brainstorming, prioritization, and problem analysis). Pest damage, low price of produce, late payment for seed cotton, and increasing input costs were the main production constraints perceived by producers. Regardless of the pest management system practised, most of the farmers adapt the recommendations of the research institute and non-government organizations to their livelihood systems. In general, farmers had a poor understanding of the key concepts underlying alternative pest control systems. Pest damage was considered important and farmers were eager to share their knowledge, perceptions and practices in pest management. The study provides the foundation for the creation of a learning platform; actors will be invited to collaborate in participatory experimental agricultural technology development linked to the farmers' needs. in order to develop sustainable pest management strategies further interactive research is proposed, involving all stakeholders.

Studies on the protective effect of botanical products against pest insects have infrequently been extended to side‐effects on natural enemies. Indirect effects of botanicals on the storability of seeds could occur through their possible negative impact on biological control agents. Four plant powders and six plant oils with a known effect on the cowpea beetle Callosobruchus maculatus (Fabr.) (Coleoptera: Bruchidae) were investigated for their effect on the beetles’ egg parasitoid Uscana lariophaga (Steffan) (Hymenoptera: Trichogrammatidae) and the larval parasitoid Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae). All treatments caused a decrease in parasitisation by U. lariophaga, and developing parasitoids of this species were affected by powders of Nicotiana tabacum (L.) and Tephrosia vogelii (Hook. f). In a two‐choice situation using a linear olfactometer, U. lariophaga was repelled by most of the oils. In a no‐choice situation, parasitisation by D. basalis was hampered by treatment with plant powders, but eggs that were laid developed normally. In a Y‐tube olfactometer, this parasitoid did not discriminate between odours of untreated and plant‐powder‐treated beans. The powders of N. tabacum and T. vogelii had stronger negative effects on the two parasitoids than the powders of Azadirachta indica (Juss.) or Blumea aurita (DC). In samples collected from untreated traditional storage facilities, subsequently treated with plant powders in the laboratory, none of the treatments could prevent the increase in beetle numbers. At 24 days after treatment, most beetles had emerged from beans treated with powders of N. tabacum and T. vogelii. Parasitoids were affected by the botanical insecticides tested here, but the powders of A. indica and B. aurita may be compatible with biological control by D. basalis.