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Can lessons learned 30 years ago contribute to reducing the impact of the fall army worm Spodoptera frugiperda in Africa and India?
Abstract
The rapid spread of the fall army worm (Spodoptera frugiperda) across sub-Saharan Africa, and now South Asia, has created surprise and distress to the smallholder farmers of both regions who face hunger and economic stress because of this pest. There has been high-quality support from the international agricultural information sector, but there has also been advice that may not be applicable to the farming systems of smallholder farmers. That comment arises from lessons learned from involvement with a similar pest outbreak of a related pest species in India starting in the mid-80s. Post-rainy season groundnut (peanut) Arachis hypogaea is a high-value crop in the coastal region of Andhra Pradesh. Changes in the management of tobacco crops to the North of the groundnut belt resulted in invasions of Spodoptera litura. The groundnut farmers responded by applying a wide range of insecticides that did nothing to protect their crops from further defoliation. Scientists from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) initiated research that enriched the knowledge of this crop-pest relationship. For instance, they showed that groundnut plants could withstand close to complete defoliation with little loss in yield. Farmers also learned that the cessation of their insecticide regime allowed natural enemies of the caterpillars to take over the management of the pests. They were showed how to enhance the populations of the coccinellids and the birds that were the key predators. ‘Citizen Scientists’ led this process. Nonand quasi-governmental organizations took over the extension process. They were provided with ongoing personal and technical support, for instance, the provision of definitive facts about the high levels of insecticide resistance, encouraging cultural control techniques, and of exploiting natural enemies, including entomopathogens. The involvement of the ICRISAT team later extended into the groundnut fields of South East Asia.
... In 2016, SSA was invaded by a trans-boundary, polyphagous insect pest: fall armyworm [Spodoptera frugiperda (J.E. Smith); FAW] [10][11][12]. FAW has caused significant crop yield losses across SSA since its arrival on the continent [13][14][15]. ...
... EFAWD was scored as follows [11]: 1 = no damage to the ear, highly resistant, 2 = damage to a few kernels (<5) or less than 5% damage to an ear, resistant, 3 = damage to a few kernels (6)(7)(8)(9)(10)(11)(12)(13)(14)(15) or less than 10% damage to an ear, resistant, 4 = damage to 16-30 kernels or less than 15% damage to an ear, partially resistant, 5 = damage to 31-50 kernels or less than 25% damage to an ear, partially resistant, 6 = damage to 51-75 kernels or more than 35% but less than 50% damage to an ear, susceptible, 7 = damage to 76-100 kernels or more than 50% but less than 60% damage to an ear, susceptible, 8 = damage to >100 kernels or more than 60% but less than 100% damage to an ear, highly susceptible, 9 = almost 100% damage to an ear, highly susceptible. ...
... This indicates that FAW donor lines included in this study have the potential to resist FAW and can be used to quickly develop hybrids that can be used in the interim to protect smallholder farmers' maize crop from FAW damage. The experiences from the Americas were reviewed as possibly helping in reducing the impact of FAW in Africa and Asia, which highlighted varietal acceptance concerns due to preferences [12] which is an issue in this study as well. The most resistant donor lines were CML67, CML121, and CML338, which have red and yellow grains and may not be readily accepted by farmers and consumers in Zimbabwe and most of ESA due to color preference for white maize [20]. ...
Fall armyworm [Spodoptera frugiperda (J./E. Smith); FAW] is negatively impacting sustainable maize production, particularly in smallholder farming systems in sub-Saharan Africa. Two sets of germplasm (commercial cultivars and experimental hybrids, and local and exotic inbred lines) were evaluated under managed and natural FAW infestation to identify FAW tolerant material with superior grain yield performance. Significant genotypic effects on foliar FAW damage, ear FAW damage, and grain yield were observed. Commercial cultivars were significantly more affected by FAW infestation than experimental hybrids, as evidenced by high foliar and ear damage scores, yet they out-yielded experimental genotypes. The introduced FAW donor lines (CML338, CML67, CML121, and CML334) showed better tolerance to FAW, individually and in hybrid combinations. Local inbred lines, SV1P, CML491, and CML 539, also showed FAW tolerance. Hybrids and open pollinated varieties were more vulnerable to FAW damage at early growth stages, but they grew out of it through the mid to late whorl stages. Inbred lines showed increasing damage as they grew to maturity. Husk cover, ear rot, anthesis date, and plant height were highly correlated with FAW tolerance. The identified local and exotic lines with FAW tolerance will contribute to FAW resistance breeding in southern Africa.
... pest, while chemical companies, entomologists, and other researchers are developing insecticides, bio-controls, and cultural-methods, respectively, to minimize crop damage that can result after infestation (Wightman, 2018). Most farmers are relying on mechanical control methods, indigenous and farmer-to-farmer advice, and recommendations from extension services Kumela et al., 2019). ...
... Bigger larvae consume large amounts of tissue and do much more damage compared to small larvae, resulting in a ragged appearance of the leaves (Figure 2d; Prasanna et al., 2018). It is also important to appreciate that foliar damage on maize may look serious but may not necessarily translate into high grain yield losses (Hruska, 2019;Wightman, 2018). Hruska (2019) reported a study carried out by the U.S. Department of Agriculture -Agricultural Research Service (USDA-ARS), in which they noted that FAW defoliation as high as 70% at 12-leaf stage could cause just about 15% grain yield loss. Fall armyworm defoliation on maize rarely goes above 50% (Hruska, 2019). ...
... The pest was detected in Yemen and India in August 2018 (FAO, 2019a;Tambo et al., 2019). As was predicted by modeling (Day et al., 2017), FAW has spread to all of the SSA countries, parts of the Middle East and Asia (Hruska, 2019;Tambo et al., 2019;Wightman, 2018), and there are chances that the pest will spread to Europe. The spread is suspected to be attributable to natural migration and through trade Day et al., 2017). ...
Fall armyworm [Spodoptera frugiperda (J.E. Smith); FAW] invasion has exacerbated maize (Zea mays L.) crop yield losses in sub‐Saharan Africa (SSA), already threatened by other stresses, especially those that are climate‐change induced. The FAW is difficult to control, manage, or eradicate, because it is polyphagous and trans‐boundary, multiplies fast, has a short life cycle and migrates easily, and lacks the diapause growth phase. In this study, FAW and its impact in Africa was reviewed, as well as past and present control strategies for this pest. Pesticides, cultural practices, natural enemies, host‐plant resistance, integrated pest management (IPM), and plant breeding approaches were examined as possible control strategies. It was concluded that an IPM control strategy, guided by cultural approaches already being used by farmers, and what can be adopted from the Americas, coupled with an insect‐resistance management strategy, is the best option to manage this pest in Africa. These strategies will be strengthened by breeding for multi‐trait host‐plant resistance through stacking of genes for different modes of control of the pest.
... A female worm can lay 2000 eggs in one period. The practices that cause an infestation of fall armyworm is not known as they travel mostly by wind dispersal (Wightman, 2018). ...
... This finding however shows that farmers do not conform with contemporary measures as stated by Wightman (2018) or the use of natural enemies (Tendeng et al., 2019). The use of natural enemies involves the use of other parasites (nematode Hexamermis sp. and two Hymenopterans Chelonus sp. and Campoletis sp.) which are enemies to fall armyworm. ...
Fall armyworm (Spodoptera frugiperda) has spread rapidly and posed numerous threats to the food security and livelihood of millions of smallholder farmers in Ghana. This study quantifies the damages of fall armyworm infestation in maize production and identifies the various methods used in controlling fall armyworm infestation. Almost all farmers 94% experienced fall armyworm infestation on their farms. They cited key common visual damages as yellowish leaves, stunted growth, poor yield quality, holes in leaves, and egg masses on leaves. Farmer’s loss an average of GH¢2616.07 to fall armyworm infestation. Pesticide application is the frequent control measure mostly used by farmers. Farmers do not mostly use biological methods for the control of the fall armyworm. The use of pesticide as a control method is however not effective as about GH¢ 3 000 per 1 acre is lost with the use of insecticides. It is recommended that the use of other control measures like the contemporary measures involving the use of birds and chickens as predators of eggs and worms of fall armyworm should be encouraged.
JEL code: Q16
... In addition to above-mentioned recommendations, a series of studies were initiated including the prospect of natural enemies Kenis et al., 2019;Agboyi et al., 2020;Koffi et al., 2020;Ngangambe and Mwatawala, 2020) assessment of damages (Sisay, Simiyu, et al., 2019), efficacy of synthetic and botanical insecticides (Sisay et al., 2019), its dynamics (Nboyine et al., 2020), forecasting of its distribution (Early et al., 2018), farmers knowledge and methods of control (Kumela et al., 2018;Hruska, 2019;Kansiime et al., 2019;Tambo et al., 2019;Toepfer et al., 2019), case studies (Wightman, 2018) and genetic characterization (Otim et al., 2018;Meagher et al., 2019). Harrison et al. (2019), pointed out the importance of conducting research on current pest management strategies used by smallholder farmers against FAW which can help to fill the existing knowledge gap for a sustainable management of the pest. ...
... It is also vital to avoid blanket application of insecticides, as per recommendation of Sisay et al. (2018). Whether or not biological control of FAW will be adopted for smallholder farmers, it is important to note that pest management approaches should be flexible and respond to local situations as predetermined solutions may not work everywhere (Wightman, 2018). ...
... This information is critical in the development of effective IPM strategies when such evidence of resistance across strategies is reported. In addition, the cessation of insecticide regimes allows natural enemies to take over FAW population regulation (Wightman 2018), especially when there is limited research-guided insecticide rotation regimes for adoption by farmers across the continent. ...
... In Ethipoia, Kumela et al. (2019) also provided evidence of farmers widely using traditional methods for FAW control. A number of non-and quasi governmental organisations are now involved in promoting citizen science including IITA on FAW control (Feldmann et al. 2019), and ICRISAT on management of groundnut pests in India (Wightman 2018). ...
Fall armyworm (FAW), Spodoptera frugiperda, is threatening food security in Africa and thus sustainable management strategies are required. The pest has spread to over 44 countries in Africa since its first detection in 2016, causing maize yield losses valued at between US6,312 million per annum. Owing to FAW’s damaging potential, many untested management strategies, including those of doubtful efficacy, are being used by smallholder farmers in Africa. We analysed existing and emerging FAW management strategies on the continent. Research and training has focussed on FAW identification, scouting, digital monitoring tools, pest distribution, natural enemy database, and FAW impact on crops. Gaps identified include lack of clear national policies and regulations, FAW identification challenges, absence of reliable and sustainable management options, and FAW insecticide resistance development. Conservation of FAW natural enemies could enhance sustainable natural control. Farmer Field Schools and mass rearing of natural enemies for augmentative release are sustainable FAW control strategies. The “push-pull” strategy in controlling FAW has potential in Africa. Existing policies and regulations to facilitate better FAW management are discussed.
... This is achieved by selecting and adopting genotypes that yield satisfactory and avoid or in some way withstand biotic and abiotic constraints (Thresh, 2003). The United States uses both native and transgenic S. frugiperda resistances to manage S. frugiperda in maize and transgenic have recorded the highest levels of resistance to the pest (Wightman, 2018). Native resistance is naturally available in the gene pool, harnessed through selection for effective use in agricultural production systems (Ni et al., 2014). ...
Fall army worm Spodoptera frugiperda (J E Smith) is a destructive insect pest that is native to tropical and subtropical regions of the Americas and later reported in Africa in 2016. The pest was first detected in Ethiopia in March 2017 and is likely to spread in the country. It is one of the most devastating pests in terms of crop loss and economic impact in developing countries like Ethiopia. It is a voracious pest that can cause significant yield loss. The most preferable host of S. frugiperda is maize and it causes serious damage by feeding on the ears of maize. Prevention of introduction, control, or eradication of S. frugiperda with appropriate measures is important. The IPM is one of the most preferred as complete elimination is not possible. There is a need to develop flexible, coordinated, and effective IPM approach combining various control measures including host plant resistance, mechanical, botanical, biological methods, cultural methods, and suitable doses of pesticides. This study generates information towards these ends.
... Application of dry sand into the whorl of effected maize plant soon after observation of FAW incidence was also very effective mechanical method to control fall armyworm infestation which is in line with the works conducted by Abate et al (2000) Removing larva of fall armyworm during vegetative stage as reported by Foster, (1989) helps the plant reduces the number of insecticidal spray required during the silking period. The adult female moth of fall armyworm lays eggs in cluster underneath of leaves, this allows easy destroying of eggs manually or by natural enemies (Wightman, 2018). The application of Neem oil @10 ml/l of water at 10 days interval also proved to effective for larval mortality as suggested by Tavares et al (2010). ...
IPM practices plays and important role in management of fall army worm and experiments conducted by KVK found that IPM practices can help in reducing the pest infestation thereby improving productivity of crops.
... Bt maize exhibits resistance to S. frugiperda, constituting over 85% of maize production in America, Brazil, and Argentina (Andama et al., 2020). Nevertheless, the use of Bt maize encounters challenges in certain countries due to high seed costs and low maize prices received by small-scale farmers (Wightman, 2018). ...
Pest infestation is a significant challenge in corn cultivation due to the potential damage it can cause, leading to reduced crop productivity or even complete crop failure. This study aims to assess the infestation of Spodoptera frugiperda on corn in Bengkulu, considering various elevations. Ten hybrids resulting from crosses between promising lines (Caps 2 x Caps 17A, Caps 3 x Caps 17A, Caps 3 x Caps 17B, Caps 5 x Caps 22, Caps 5 x Caps 17B, Caps 15 x Caps 22, Caps 17B x Caps 23, Caps 17A x Caps 17B, Caps 17A x Caps 22, Caps 22 x Caps 23) and three commercial hybrid varieties (Bonanza, Paragon, and Secada) were evaluated across three locations at different elevations: lowland (30 meters above sea level) (masl), midland (600 masl), and highland (1000 masl). The assessment focused on the extent of damage and the plant’s resistance to S. frugiperda infestations. The infestation of S. frugiperda is higher at an elevation of 30 masl compared to locations at 600 masl and 1000 masl. Scoring leaf damage caused by S. frugiperda infestation at 30 masl: 2.73–4.86, at 600 masl: 2.73–3.55, and at 1000 masl: 2.4–3.37.
... Recent research reports have shown that S. frugiperda is an invasive pest in many countries in Africa and Asia (Fan et al., 2020;Firake and Behere, 2020;Jing et al., 2020;Lee et al., 2020). These countries have favorable climatic conditions and a large variety of plants that can serve as hosts, and, as such, S. frugiperda is likely to spread rapidly and cause serious damage to local plants (Wightman, 2018;EFSA, 2020). An estimated $US13 billion in crop losses occur every year in Africa as a result of the fall armyworm. ...
Background
‘The fall armyworm, Spodoptera frugiperda’, represents a significant threat to maize production, a major staple crop in Asian countries.
Methods
In pursuit of more effective control of this insect pest, our study assessed the physiological and biochemical effects of the entomopathogenic fungus Metarhizium anisopliae against the larvae of S. frugiperda.
Results
Results revealed that, following nine days of treatment, a high concentration of conidia (1.5x10⁷ conidia/mL⁻¹) was toxic to all stages of larvae (second to fifth instar), resulting in 97% mortality of the second instar, 89% mortality of the third instar, 77% mortality of the fourth instar, and 72% mortality of fifth instar. All larval instars were found to have dose-dependent mortality effects. Treated S. frugiperda larvae further displayed significant physiological, morphological, and behavioral changes. Here, treated larvae displayed significantly lower levels of acetylcholinesterase, α-carboxylesterase, and β-carboxylesterase enzyme activity when compared to control groups. Treated larvae underwent an outward morphological change as the result of a decrease in the exterior cuticle of the anal papillae and a demelanization of the interior cuticle. Treated larvae also exhibited abnormal feeding behaviors as a consequence of the negative impact of conidia treatment on the neuromuscular system. Investigation into the effect of M. anisopliae on the non-target organism, the earthworm Eudrilus eugeniae, revealed that M. anisopliae conidia did not produce significant pathogenicity following three days of treatment. Furthermore, histological analysis revealed no significant effect of the entomopathogenic fungi on the gut tissue of the non-target organism.
Conclusion
This study highlights the potential of M. anisopliae in the control of S. frugiperda.
... The fall armyworm (FAW) has caused varying degrees of crop damage in several countries. The impact of FAW invasion on resource-poor farmers in sub-Saharan Africa (SSA) has worsened (Wightman, 2018). A report revealed that in the absence of proper management measures, FAW significantly reduced yields by 21 to 53 percent annually in twelve maize-producing countries in Africa . ...
... The whorl and young leaves, ears and tassels are the most consumed plant structures by FAW (Almeida Sarmento et al. 2002). Still, foliar damage of maize may not necessarily translate to high grain yield losses in contrast to ear damage (Kumar 2002;Wightman 2018;Hruska 2019;Prasanna et al. 2021). ...
The fall armyworm (FAW), Spodoptera frugiperda (JE Smith, 1797), is a serious pest of several crops, particularly maize and other cereals. It has long been known as a pest in the Americas and has invaded most of Africa and parts of the Middle East, Asia, and Australia in the last six years. Its new status as an invasive species causing serious damage in many regions worldwide has highlighted the need for better understanding and has generated much research. In this article, we provide a comprehensive review of FAW covering its (i) taxonomy, biology, ecology, genomics, and microbiome, (ii) worldwide status and geographic spread, (iii) potential for geographic expansion and quarantine measures in place, and (iv) management including monitoring, sampling, forecasting, biological control, biopesticides, agroecological strategies, chemical control, insecticide resistance, effects of insecticides on natural enemies, as well as conventional and transgenic resistant cultivars. We conclude with recommendations for research to enhance the sustainable management of FAW in invaded regions.
... Smith) (Lepidoptera: Noctuidae), is one of the main arthropod pests present in different crops of economic importance and generally reaches high population density, causing large economic losses. This insect is native to the Americas, however recently its presence has been detected in Africa and Asia (Kasoma et al., 2020;Wightman, 2018). It is a polyphagous species that feeds on 353 species of host plants in the Americas (Montezano et al., 2018). ...
The objective of this study was to evaluate the biological and nutritional characteristics of Spodoptera frugiperda (Lepidoptera: Noctuidae), an arthropod pest widely distributed in agricultural regions, after exposure to nano-CeO2 via an artificial diet and to investigate the presence of cerium in the body of this insect through X-ray fluorescence mapping. Nano-CeO2, micro-CeO2, and Ce(NO3)3 were incorporated into the diet (0.1, 1, 10, and 100 mg of Ce L⁻¹). Cerium was detected in caterpillars fed with diets containing nano-CeO2 (1, 10 and 100 mg of Ce L⁻¹), micro-CeO2 and Ce(NO3)3, and in feces of caterpillars from the first generation fed diets with nano-CeO2 at 100 mg of Ce L⁻¹ as well. The results indicate that nano-CeO2 caused negative effects on S. frugiperda. After it was consumed by the caterpillars, the nano-CeO2 reduced up to 4.8% of the pupal weight and 60% of egg viability. Unlike what occurred with micro-CeO2 and Ce(NO3)3, nano-CeO2 negatively affected nutritional parameters of this insect, as consumption rate two times higher, increase of up to 80.8% of relative metabolic rate, reduction of up to 42.3% efficiency of conversion of ingested and 47.2% of digested food, and increase of up to 1.7% of metabolic cost and 8.7% of apparent digestibility. Cerium caused 6.8 to 16.9% pupal weight reduction in second generation specimens, even without the caterpillars having contact with the cerium via artificial diet. The results show the importance of new ecotoxicological studies with nano-CeO2 for S. frugiperda in semi-field and field conditions to confirm the toxicity.
... Removing larva of fall armyworm during vegetative stage of plant reduces the number of insecticidal spray required during the silking period (Foster, 1989). As the adult female moth of fall armyworm lays eggs in cluster underneath of leaves, this allows easy destroying of eggs manually or by natural enemies (Wightman, 2018). ...
Spodoptera frugiperda, commonly known as Fall Armyworm (FAW), is amongst the most terrifying pests of maize in Latin America, which unexpectedly appeared in Nepal in 2019 and spread expeditiously. Estimates of maize crop losses due to this pest are vital in order to compare the effect of these losses with the convenient of controlling FAW and suggest pertinent controlling technology and methods. Nepal is predominantly an agrarian nation thus, maize is grown substantially. However, climatic conditions of Nepal favor the outbreaks of pests such as FAW in many maize grown areas. On the grounds that most of the people of hill and mountainous regions depend on maize for their staple food, pests have appeared to be a great threat to cereal production. It causes considerable injuries to maize by feeding on leaf whorls, ears and tassel which often leads to total yield loss. Yet, agriculture is an economic activity, even among subsistence farmers in Nepal. Seeing high potential losses caused by FAW, different control methods have been proposed. This pest demands meticulous and stepwise plan for its management. This review emphasized on adoption of IPM methods of pests’ control, which is the integration of biological, cultural, physical, chemical, and technological approaches. Meanwhile, early warning systems, though poorly developed in Nepal, can be highlighted for further studies and for further research work.
... It is also vital to avoid blanket application of insecticides, as per recommendation of Sisay [32]. Whether or not biological control of FAW will be adopted for smallholder farmers, it is important to note that pest management approaches should be flexible and respond to local situations as predetermined solutions may not work everywhere [48]. ...
The alien invasive insect pest Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), commonly referred to as fall armyworm (FAW), is causing significant losses to maize production in Africa since its detection in 2016. As an emergency response, governments in several countries distributed and/or promoted massive use of synthetic insecticides among smallholder farmers to fight FAW. The inappropriate use of synthetic insecticides by non-trained and ill-equipped farmers raises environmental and health concerns. This study aimed to assess the occurrence of native parasitoids of FAW, their parasitism rates, and relative abundance in the central province of Manica, Mozambique. A field collection of FAW egg masses and larvae was conducted from May to August 2019 (dry season of the 2018/2019 cropping season) and in December 2019 and January 2020 (rainy season of 2019/2020 cropping season). A total of 101 egg masses and 1444 larvae of FAW were collected from infested fields. Five larval parasitoids were recorded, but no egg parasitism was observed. Coccygidium luteum Brullé (Hymenoptera: Braconidae) and Drino quadrizonula Thomson (Diptera: Tachinidae) were the primary parasitoids. Maximum parasitism of 23.68% and 8.86% and relative abundance of 100 and 96.3 were recorded for C. luteum and D. quadrizonula, respectively. Total parasitism by different parasitoid species was at 9.49%. Cultural practices favoring the action of these parasitoids should be advocated.
Insecticides and genetically modified Bt crops are the main tools for control of the fall armyworm, Spodoptera frugiperda (J.E. Smith). Since its invasion of Africa, the Far East, and Australia where Bt crops are largely absent, insecticide use has increased and reduced susceptibility to several insecticides used for decades in its native distribution area have been reported. Poor efficacy at field-level is sometimes incorrectly ascribed to pest resistance, while numerous other factors influence efficacy at field-level. In this paper, we review the history of insecticide resistance in S. frugiperda and discuss the influence that life history traits, migration ecology, and chemical control practices may have on control efficacy and resistance evolution. The indirect role that poor national policies have on pesticide use practices, and indirectly on control efficacy and selection pressure is discussed. Evidence shows that local selection for resistance drives resistance evolution. Integrated pest management, rather than reliance on a single tactic, is the best way to suppress S. frugiperda numbers and the over-use of insecticides which selects for resistance.
Deploying maize varieties with fall armyworm (Spodoptera frugiperda [J.E. Smith]; FAW) resistance, desirable product profiles (PPs) and climate resilience is fundamental for food and economic security in sub‐Saharan Africa (SSA). This study reviewed and identified challenges and opportunities for effective and accelerated breeding of demand‐led maize hybrids with FAW resistance and adaptation to the diverse agro‐ecologies of SSA. Lessons were drawn on improving breeding efficiency through adequate genetic variation delivered via prebreeding programmes, speed breeding and a reduced breeding stage plan. Appropriate PPs aligned with demand‐led breeding approaches were highlighted as foundations for variety design and commercialization. Challenges to accelerated FAW resistance breeding in maize included inadequate funds and modern tools; poor adaptation of some exotic donor parental lines; lack of information on FAW resistance among local varieties; lack of integration of molecular markers associated with FAW resistance and agronomic traits into selection plans; and limited infrastructure for FAW rearing and germplasm screening. Integration of modern breeding tools and scientific innovations were recommended for accelerated development and release of FAW resistant and market‐preferred maize varieties.
The development and reproduction of the fall armyworm (FAW), Spodoptera frugiperda, which were reared on artificial diets containing nano-graphene oxide (GO), were determined based on age-stage, two-sex life table analysis. The results showed that GO had adverse effects on FAWs. Compared with the control, the duration of the egg stage and first, second, and sixth instar larval stages increased with increasing GO concentrations; however, the lifespan of male and female adults decreased with increasing GO concentrations. Weights of FAW pupae that were supplied with GO-amended diets increased by 0.17–15.20% compared to the control. Intrinsic growth, limited growth, and net reproductive rates of FAWs feeding on GO supplemented diets were significantly lower than the control, while mean generational periods (0.5 mg/g: 38.47; 1 mg/g: 40.38; 2 mg/g: 38.42) were significantly longer than the control. The expression of genes encoding vitellogenin (Vg) and vitellogenin receptor (VgR) expression was abnormal in female FAW adults feeding on GO-amended diets; the number of eggs laid decreased relative to the control, but Vg expression increased. In conclusion, GO prolonged the developmental period of FAWs, decreased fecundity, and led to a decline in the population size. The study provides a basis for the rational use of GO as a pesticide synergist for FAW control.
Community (or citizen) science, the involvement of volunteers in scientific endeavors, has a long history. Over the past few centuries, the contributions of volunteers to our understanding of patterns and processes in entomology has been inspiring. From the collation of large-scale and long-term data sets, which have been instrumental in underpinning our knowledge of the status and trends of many insect groups, to action, including species management, whether for conservation or control, community scientists have played pivotal roles. Contributions, such as pest monitoring by farmers and species discoveries by amateur naturalists, set foundations for the research engaging entomologists today. The next decades will undoubtedly bring new approaches, tools, and technologies to underpin community science. The potential to increase inclusion within community science is providing exciting opportunities within entomology. An increase in the diversity of community scientists, alongside increasing taxonomic and geographic breadth of initiatives, will bring enormous benefits globally for people and nature.
Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Fall armyworm, Spodoptera frugiperda (J E Smith), an economically important pest native to tropical and sub-tropical America has recently invaded Africa, causing substantial damage to maize and other crops. We evaluated functionality of a companion cropping system, ‘climate-adapted push-pull’, developed for control of cereal stemborers in drier agro-ecologies, as an added tool for the management of fall armyworm. The technology comprises intercropping maize with drought-tolerant greenleaf desmodium, Desmodium intortum (Mill.) Urb., and planting Brachiaria cv Mulato II as a border crop around this intercrop. Protection to maize is provided by semiochemicals that are emitted by the intercrop that repel (push) stemborer moths while those released by the border crop attract (pull) them. 250 farmers who had adopted the technology in drier areas of Kenya, Uganda and Tanzania were randomly selected for the study during the long rainy season (March-August) of 2017. Each farmer had a set of two plots, a climate-adapted push–pull and a maize monocrop. Data were collected in each plot on the number of fall armyworm larvae on maize, percentage of maize plants damaged by the larvae and maize grain yields. Similarly, farmers' perceptions of the impact of the technology on the pest were assessed using a semi-structured questionnaire. Reductions of 82.7% in average number of larvae per plant and 86.7% in plant damage per plot were observed in climate-adapted push-pull compared to maize monocrop plots. Similarly, maize grain yields were significantly higher, 2.7 times, in the climate-adapted push-pull plots. Farmers rated the technology significantly superior in reducing fall armyworm infestation and plant damage rates. These results demonstrate that the technology is effective in controlling fall armyworm with concomitant maize grain yield increases, and represent the first documentation of a technology that can be immediately deployed for management of the pest in East Africa and beyond.
An annotated checklist of the Coccinellidae (Coleoptera) of the Indian subcontinent (excluding the subfamily Epilachninae) comprising 400 species (including six subspecies) under 79 genera, 22 tribes and five subfamilies, is given. The current combination, original citation, synonyms, distribution and type depository (wherever known) are given for the included species. Three new specific synonymies [Harmonia breiti Mader = H. expallida (Weise); Ortalia yunnanensis Pang & Mao = O. horni Weise; and Scymnus picescens Gorham = S.fuscatus Boheman], one generic synonymy [Aponephus Booth = Nephus Mulsant] and six new combinations [Coelophora perrotteti Mulsant and C. unicolor (Fabricius) with Phrynocaria Timberlake, Platynaspis bimaculata Pang & Mao with Platynaspidius Miyatake, Aponephus lentiformis Booth with Nephus Mulsant, Pseudoscymnus luteoniger Canepari with Clitostethus Mulsant, and Sukunahikona popei Vazirani with Scotoscymnus Weise] are proposed. A list of coccinellids introduced into the region, but not established, is also given.
A strain of the fall armyworm, Spodoptera frugiperda (J.E. Smith), collected from corn in Citra, Florida, showed high resistance to carbaryl (562-fold) and methyl parathion (354-fold). Biochemical studies revealed that various detoxification enzyme activities were higher in the field strain than in the susceptible strain. In larval midguts, activities of microsomal oxidases (epoxidases, hydroxylase, sulfoxidase, N-demethylase, and O-demethylase) and hydrolases (general esterase, carboxylesterase, β-glucosidase) were 1.2- to 1.9-fold higher in the field strain than in the susceptible strain. In larval fat bodies, various activities of microsomal oxidases (epoxidases, hydroxylase, N-demethylase, O-demethylases, and S-demethylase), glutathione S-transferases (CDNB, DCNB, and p-nitrophenyl acetate conjugation), hydrolases (general esterase, carboxylesterase, β-glucosidase, and carboxylamidase) and reductases (juglone reductase and cytochrome c reductase) were 1.3- to 7.7-fold higher in the field strain than in the susceptible strain. Cytochrome P450 level was 2.5-fold higher in the field strain than in the susceptible strain. In adult abdomens, their detoxification enzyme activities were generally lower than those in larval midguts or fat bodies; this is especially true when microsomal oxidases are considered. However, activities of microsomal oxidases (S-demethylase), hydrolases (general esterase and permethrin esterase) and reductases (juglone reductase and cytochrome c reductase) were 1.5- to 3.0-fold higher in the field strain than in the susceptible strain. Levels of cytochrome P450 and cytochrome b5 were 2.1 and 1.9-fold higher, respectively, in the field strain than in the susceptible strain. In addition, acetylcholinesterase from the field strain was 2- to 85-fold less sensitive than that from the susceptible strain to inhibition by carbamates (carbaryl, propoxur, carbofuran, bendiocarb, thiodicarb) and organophosphates (methyl paraoxon, paraoxon, dichlorvos), insensitivity being highest toward carbaryl. Kinetics studies showed that the apparent Km value for acetylcholinesterase from the field strain was 56% of that from the susceptible strain. The results indicated that the insecticide resistance observed in the field strain was due to multiple resistance mechanisms, including increased detoxification of these insecticides by microsomal oxidases, glutathione S-transferases, hydrolases and reductases, and target site insensitivity such as insensitive acetylcholinesterase. Resistance appeared to be correlated better with detoxification enzyme activities in larval fat bodies than in larval midguts, suggesting that the larval fat body is an ideal tissue source for comparing detoxification capability between insecticide-susceptible and -resistant insects.
A new perspective on the global food security situation and highlights the need for seeking a common vision and implementing global planning to define the manner in which the human species will manage its food security. The basic question of 'Is there enough food' is examined in general and then in some detail. The history of food production is reviewed in the hope that lessons can be learned from the past. But even after ten thousand years of experience we are not able to feed adequately about a third of our total population, despite what statistics can be made to tell us. Intensive agriculture has stripped out the nutrients that support plant growth and marginalised extensive tracts of land. The global solution to feed the growing population has been and continues to be - produce more food. Even during the last 30 years, about 95 percent of global research investments have focused mainly on increasing productivity. However about a third of the food produced, sufficient to feed over two billion hungry people, is lost or wasted in the food value chain. Climate change is another confounding factor that impinges on our discussions. Pests of all kinds continue to destroy food before and after it is harvested, even though the technology to protect it is available. A huge amount of food is wasted in value chains, particularly at the domestic level. Global food production systems are exposed to unprecedented biosecurity risks posed by invasive harmful organisms and this trend is likely to further exacerbate as current approach to biosecurity is based on the notional premise that lines on maps and the legislation that goes with them is sufficient to halt epidemics. Solutions include extending the number of cultivated plant and animal species to include those that can prosper in what are currently considered to be extreme environments.
There have been four major reviews of the literature discussing the insects living on groundnut plants since 1973 (Feakin, 1973; Smith and Barfield, 1982; Wightman et al., 1990 Wightman et al., 1990; Gahukar, 1992). There are also several more concise accounts dealing with pest problems in general (e.g. Wightman and Amin, 1988; Wightman et al., 1989Wightman et al., 1989; Lynch and Douce, 1992), specific topics, such as host plant resistance (Lynch, 1990), and discrete geographical zones such as India (Amin, 1988), developed countries (Biddle et al., 1992) and southern Africa (Wightman, 1988a; Wightman, 1989; Sohati and Sithanantham, 1990; Sithanantham et al., 1990). Feakin (1973), Redlinger and Davis (1982), Dick (1987a), Dick (1987b) and Wightman et al., 1990 Wightman et al., 1990 provide details of the insect pest problems associated with stored groundnut and their management in developed and developing countries. There is little more to add to what has already been recorded about the post-harvest pests of groundnut — the limited coverage given to them in this chapter should not be taken as an indication that they lack importance. Thus, although the general literature up to 20 years ago was somewhat sparse (despite the publication of a large body of information in primary sources), there have since been attempts to redress the situation.
Developmental thresholds and thermal requirements for different stages of Spodoptera litura (F.) fed on groundnut leaves were determined under constant laboratory conditions and in the field. An average of 64 degree-days (DD) above a threshold of 8°C was required from oviposition to egg hatch; the larval period required 303 DD and pupal stage 155 DD above a 10°C threshold; females needed 29 DD above a 10.8°C threshold from emergence to oviposition. Fifth and sixth instars accounted for about 50%of the total larval requirement under laboratory and field conditions. The response of various stages of S. litura to temperatures under constant laboratory conditions was similar to that under field conditions. The upper developmental threshold temperature of all stages was 37°C; 40°C was lethal.
Reducing the losses from crop pests will help to increase food availability and boost economic growth in sub-
Saharan Africa (SSA). However, the existing crop protection paradigm that relies on synthetic agrochemical pesticides has had only a marginal impact on the productivity of many poor smallholder farmers who constitute a major segment of agriculture in SSA. This is primarily because many of them are not able to afford or access these imported chemicals. A solution to this crop protection problem may be to harness biological resources that are locally available, such as endemic insect natural enemies and indigenous pesticidal plant materials.
Two specific examples of this already under development in Africa are the use of the pesticidal plant, Tephrosia
vogelii, and the harvesting of the endemic insect baculovirus, Spodoptera exempta nucleopolyhedrovirus (SpexNPV). Both of these can be produced locally and have shown promise in trials as inexpensive and effective tools for pest control in Africa and their use is currently being scaled up and evaluated by African networks of researchers. A focus on these systems illustrates the potential for using locally-available natural resources for improved crop protection in Africa. The consideration of these pesticidal plants and insect natural enemies in the wider context of natural capital that provide valuable ecosystem services (including pest control), will facilitate greater recognition of their true economic and societal worth. While both of these model systems show promise, there are also very significant challenges to be overcome in developing production, supply and marketing systems that are economically viable and sustainable. The regulatory environment must
also evolve to accommodate and facilitate the registration of new products and the establishment of appropriate supply chains that share the benefits of these resources equitably with the local communities from which they are harvested.
Stand management in lucerne (Medicago sativa) was used to conserve natural enemies and reduce overwintering aphid (Acyrthosiphon kondoi and A. pisum) numbers. Comparison of stem and sweep net counts allowed sweep counts of predators to be calibrated, and showed that the parasite, Aphidius eadyi, and the predator, Micromus tasmaniae, were best synchronised with lucerne aphid populations. Lucerne reservoirs created by strip-cutting or strip-grazing were associated with lower aphid populations and lower ratios of aphids:predators, except in spring. Laboratory-bred parasites were released to augment early spring populations, but slow dispersal reduced their impact. Winter grazing and herbicide treatment significantly reduced aphid populations in spring. Insecticide trials confirmed the place of pirimicarb as a selective aphicide in integrated programmes.
The susceptibility of Spodoptera frugiperda (1. E. Smith) to methomyl. diazinon, and permethrin in relation to larval development was investigated. Increased LD,,,s of these insecticides were associated with increasing larval instars. Sixth instars were 135-, 154-, and 236-fold more tolerant of methomyl, diazinon, and permethrin, respectively, than were 3rd instars on a per-larva basis; the tolerances became 3. I -, 3.2-, and 5.6-fold, respectively, on a body weight basis. In all instances, a larger difference in tolerance was observed between 5th- and 6th-instars than between any other two successive instars. The fact that injection of methomyl into the 5th- and 6th-instars thereby bypassing the cuticle, did not alter the tendency suggests that the large increases in tolerance in the final instars were not related to cuticular penetration. Biochemical studies revealed that increased midgut aldrin epoxidase activity was associated with increased larval instars on a protein basis. A similar pattern was also observed for the midgut glutathione S-transferase activity, whereas the midgut esterase activity appeared to be higher in younger instars. Piperonyl butoxide, the well-known inhibitor of microsomal oxidases, enhanced the toxicity of these insecticides in this insect. Changes in microsomal oxidase activity correlate well with the toxicity of these insecticides to fall armyworm larvae.
1. Onset and spread of the severe outbreaks of African armyworm, Spodoptera exempta (Walk.), over Ethiopa, Kenya, Tanzania and Burundi in late 1984 have been analysed in relation to trap and weather records.
2. Although first outbreaks in each country appeared progressively further south, winds on the best estimated dates of moth concentration and egg laying blew from directions precluding moth movements between them.
3. Such independently developing outbreaks are called ‘primary’ to distinguish them from any ‘secondary’ outbreaks that may develop from them.
4. Parent moths giving rise to all seven areas of primary outbreaks were derived from low-density populations that had persisted through the dry season, probably near the coast of East Africa.
5. Primary outbreaks developed on the south-eastern sides of individual rainstorms over the highlands, most likely because windborne moths were concentrated there by convergent winds.
6. Of the secondary outbreaks within Kenya, Tanzania and Burundi, most were derived from only one area of primary outbreaks in Kenya, which were therefore critical for effective control of spread; the paucity of other secondaries was presumably due to a lack of timely rainstorms or other concentrating mechanisms.
Twenty-two strains of the tobacco caterpillar, Spodoptera litura (F.) (Lepidoptera: Noctuidae), collected from groundnut crops of eight locations in Andhra Pradesh, India, between 1991 and 1996 were assayed in the F1 generation for resistance to commonly used insecticides. Resistance levels ranged as follows: cypermethrin, 0·2- to 197-fold; fenvalerate, 8- to 121-fold; endosulfan, 1-to 13-fold; quinalphos, 1- to 29-fold; monocrotophos, 2- to 362-fold and methomyl, 0·7- to 19-fold. In nearly all strains pre-treatment with the metabolic inhibitor, piperonyl butoxide, resulted in complete suppression of cypermethrin resistance (2- to 121-fold synergism), indicating that enhanced detoxification by microsomal P450-dependent monooxygenases was probably the major mechanism of pyrethroid resistance. Pre-treatment with the synergist DEF, an inhibitor of esterases and the glutathione S-transferase system, resulted in a 2- to 3-fold synergism with monocrotophos indicating that esterases and possibly glutathione S-transferases were at least to some extent contributing to organophosphate resistance. © 1997 SCI.
The research agendas of psychologists and economists now have several overlaps, with behavioural economics providing theoretical and experimental study of the relationship between behaviour and choice, and hedonic psychology discussing appropriate measures of outcomes of choice in terms of overall utility or life satisfaction. Here we model the relationship between values (understood as principles guiding behaviour), choices and their final outcomes in terms of life satisfaction, and use data from the BHPS to assess whether our ideas on what is important in life (individual values) are broadly connected to what we experience as important in our lives (life satisfaction).
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