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Invasive alien species (IAS) continue to shape the global landscape through their effects on biological diversity and agricultural productivity. The effects are particularly pronounced in Sub-Saharan Africa, which has seen the arrival of many IAS in recent years. This has been attributed to porous borders, weak cross border biosecurity, and inadequate capacity to limit or stop invasions. Prediction and early detection of IAS, as well as mechanisms of containment and eradication, are needed in the fight against this global threat. Horizon scanning is an approach that enables gathering of information on risk and impact that can support IAS management. A study was conducted in Ghana to establish two ranked lists of potential invasive alien plant pest species that could be harmful to agriculture, forestry, and the environment, and to rank them according to their potential threat. The ultimate objective was to enable prioritization of actions including pest risk analysis, prevention, surveillance and contingency plans. Prioritisation was carried out using an adapted version of horizon scanning and consensus methods developed for ranking IAS worldwide. Following a horizon scan of invasive alien species not yet officially present in Ghana, a total of 110 arthropod and 64 pathogenic species were assessed through a simplified pest risk assessment. Sixteen species, of which 14 were arthropods and two pathogens, had not been recorded on the African continent at the time of assessment. The species recorded in Africa included 19 arthropod and 46 pathogenic species which were already recorded in the neighbouring countries of Burkina Faso, Côte d'Ivoire, and Togo. The majority of arthropod species were likely to arrive as contaminants on commodities, followed by a sizable number which were likely to arrive as stowaways, while some species were capable of long distance dispersal unaided. The main actions suggested for species that scored highly included full pest risk analyses and, for species recorded in neighbouring countries, surveys to determine their presence in Ghana were recommended. [ABSTRACT FROM AUTHOR]

The fall armyworm, Spodoptera frugiperda, an American Lepidoptera, is invasive in Africa and Asia and currently one of the most damaging cereal pests in the tropics. The ichneumonid parasitoid, Eiphosoma laphygmae, is a potential classical biological control agent. We assessed existing knowledge on biology, identified natural distributions, collated reported parasitism rates from field studies and determined which other parasitoids co-occurred. We discussed the suitability of E. laphygmae for classical biological control as well as identified limitations and knowledge gaps. We conducted a systematic literature review and had 185 hits, retaining 52 papers. Reports on the natural distribution of E. laphygmae were restricted to the American tropics, ranging from North-East Mexico to Sao Paulo State, Brazil. There were only two single and unconfirmed records of it on other hosts, suggesting that the parasitoid may be specific to S. frugiperda, but this needs confirmation. In fields where E. laphygmae occurred naturally, it was the second most important contributor to fall armyworm mortality, after the braconid Chelonus insularis. On average, E. laphygmae parasitized 4.5% of fall armyworm in field studies. The highest parasitism rates were from Costa Rica (13%) and Minas Gerais, Brazil (14.5%). However, these parasitism rates are probably largely underestimated because of likely biases in sampling and parasitism rate calculations. Eiphosoma laphygmae appeared to establish better in more diverse, weedy systems. As African farming systems often have high diversity, this may favour the establishment and parasitism of E. laphygmae if eventually introduced as a classical biological control agent. [ABSTRACT FROM AUTHOR]

In Burkina Faso, the leaf beetle Aphthona whitfieldi is the main insect pest of the biofuel plant Jatropha curcas that affects plant growth and seed yield. This study was conducted on-station and on-farm in the district of Léo, southern Burkina Faso, in 2015. It aimed at evaluating the yield losses that A. whitfieldi inflicts to J. curcas. The first experiment used 25 caged trees during the first year of fruit production, on which various numbers of beetles were released. When 200 beetles were released/cage, the defoliation level reached 55% and caused 61% of yield loss. Releases of 400 or more beetles/cage caused a defoliation level of at least 74% and seed losses of 99%. On-farm observations were made on foliage damage and yield loss in three different types of plantations, i.e. sole plantations, plantations intercropped with food crops and hedges. These observations showed that defoliation levels over 50% were common in the three types of plantations, resulting in very low yields. This study shows the importance of beetle damage in the cultivation of J. curcas. It highlights the leaf beetle as main limiting constraint for the production of J. curcas in Burkina Faso. [ABSTRACT FROM AUTHOR]

The box tree moth Cydalima perspectalis (Walker) (Lepidoptera: Crambidae) (BTM) is a native moth throughout eastern Asia, having recently become invasive in Europe (2007) where it feeds on boxwood (= box tree), Buxus spp. The moth rapidly spread across Europe and the Caucasus causing damage to both ornamental and wild Buxus. In 2018, C. perspectalis was found in Toronto, ON, Canada, and has since spread south into the US. To better predict where the moth will establish and have significant impact on ornamental trade in North America, we used most recent scientific literature and distribution points to update the temperature and diapause indices of an existing ecoclimatic CLIMEX model. The model parameters provided a good fit for the potential distribution of BTM compared to its known distribution across eastern Asia and in Europe. Interestingly, our results suggest that the current native distribution in Asia is incomplete and that further expansion is also possible in its introduced range, especially in northern Europe, along the Mediterranean coast of Africa, and eastward to central Russia. In North America, the model predicts that most of North America should be climatically suitable for the moth's establishment, with the exception of Alaska and the northern territories of Canada, as well as higher elevations in the Rocky Mountains and southern hot and dry areas. Our study highlights the importance of the CLIMEX model to assess the risk of BTM spreading in its newly invaded areas, especially North America, and its use to help make decisions in terms of regulatory dispersal restrictions and choice of management options. [ABSTRACT FROM AUTHOR]

Simple Summary: The black soldier fly is a tropical and subtropical fly that is increasingly used in animal feed worldwide. Its larvae develop in organic plant or animal matter and agro-industrial by-products. In Africa, they represent a source of protein that can help improve local poultry feed rations. The aim of this study was to improve the technique of black soldier fly larvae production by using local substrates (poultry droppings, cotton cake, brewery waste, and local beer waste) for animal feed in Burkina Faso. This study showed that the production of black soldier fly larvae by exposing substrates to naturally occurring flies is possible but that yields strongly vary according to the season and the substrates and types of containers used. These results provide important information for the development of sustainable insect-based poultry feed production methods in Sub-Saharan Africa. Larvae of Hermetia illucens are a valuable source of protein for animal feed that can be produced by exposing animal and agro-industrial wastes to naturally occurring flies. The objective of this study was to improve techniques for obtaining H. illucens larvae to feed livestock in Burkina Faso. An experiment was conducted to determine the most favourable substrates and seasons for larval production. The substrates used were poultry manure, local beer waste, local beer waste mixed with poultry manure, cottonseed cake, and industrial brewery waste mixed with poultry manure. The production of larvae was carried out in four different seasons. The effect of the container's oviposition area (0.07 m2, 0.09 m2, and 0.11 m2) and the type of container (terracotta, plastic, and iron) on larval production was also assessed. The produced larval biomass was high during, or just after, the rainy season but very low during the cool dry and hot dry seasons. Yields were higher with local beer waste mixed with poultry manure followed by local beer waste and cottonseed cake. The average mass of H. illucens larvae increased slightly with the oviposition area for the same amount of substrate. Iron and terracotta containers provided better results than plastic containers. The suitability of this production method for H. illucens larvae production is discussed. [ABSTRACT FROM AUTHOR]

The outbreak of the fall armyworm, Spodoptera frugiperda, in Africa has led to several recommendations of insecticides, including biopesticides. However, the effects of these products on the environment, especially on parasitoids have not been assessed under field conditions. Here, we investigated the effect of commonly used biopesticides on S. frugiperda management and larval parasitoids of S. frugiperda in northern Ghana. The experiments were conducted both on-station in Wa and Nyankpala and on-farm in Wa during the 2020 rainy season. Active ingredients tested included neem oil (3% Azadirachtin), maltodextrin (282 g/l), 55% Bacillus thuringiensis (Bt) combined with 45% Monosultap, and a Pieris rapae granulosis virus combined with 5% Bt. A chemical insecticide based on emamectin benzoate and acetamiprid was used as positive control while non-treated maize plots were considered as untreated control. The two most abundant parasitoids in Wa were Coccygidium luteum and Chelonus bifoveolatus, while in Nyankpala they were C. luteum and Meteorus sp. Total larval parasitism rates on-station were 18.7% and 17.6% in Wa and Nyankpala, respectively, and 8.8% in Wa on-farm. Parasitoid species diversity and evenness indexes did not vary among treatments, but parasitism rates were significantly lower with the chemical on-station in Wa and with the virus and Bt product in Nyankpala. Untreated maize plots showed the highest larval density and plant damage, the highest cob damage, and generated the lowest yields. The other treatments showed hardly any difference in cob damage and yields, suggesting that biopesticides should be preferred over chemical pesticides for S. frugiperda control. [ABSTRACT FROM AUTHOR]

The 6/04 standard of the European and Mediterranean Plant Protection Organisation (EPPO) on the safe use of biological control is a decision-support scheme (DSS) for the import and release of biological control agents in Europe. It was recently developed by the Joint EPPO/International Organisation of Biological Control (IOBC) Panel on Biological Control Agents. The DSS can be used to assess the potential environmental impacts of biological control agents. It is valid for different types of biological control: classical and augmentative biological control of invertebrates, pathogens and weeds. However, the DSS is not yet widely implemented in Europe and, during preliminary trials, it was found that its broad range of usages could lead to some confusion or misunderstandings, as well as requiring unnecessary information in some cases. Thus, the scheme was modified to specifically assess classical biological control against plant pests, i.e. the introduction of exotic natural enemies of plant pests for establishment and long-term control. The new version of the scheme was then tested on two parasitoids that are presently being released in Europe, the figitid Ganaspis cf. brasiliensis against the spotted wing drosophila Drosophila suzukii and the mymarid Cleruchoides noackae against the Eucalyptus bronze bug Thaumastocoris peregrinus. Both parasitoids were successfully assessed with the new version of the DSS. No major issues were encountered during the assessments and most questions were answered with low levels of uncertainty. Both assessments concluded that the parasitoids were safe to release in the impact assessment areas, with positive impacts exceeding negative impacts. Suggestions for potential improvements are provided. [ABSTRACT FROM AUTHOR]

Simple Summary: Marchalina hellenica (Hemiptera: Marchalinidae) is a significant contributor to annual honey production in Greece and Turkey, where it is endemic. It was initially described as parthenogenetic, producing only females. The exact reproduction strategy of this species remains unknown. For this reason, we studied the emergence pattern of male individuals in Greece for two consecutive years (2021 and 2022). Furthermore, we examined the genetic variation among 15 geographically distant populations of M. hellenica in Greece using a mitochondrial DNA marker and compared the results with data from Turkey. This study documents the existence of an additional M. hellenica population in its native range that repeatedly produces males, suggesting a previously unknown role for males in the species' reproduction. The Greek and Turkish populations exhibited a strong genetic affinity, while the genetic pattern in Greece seems to have been obscured by human-aided dispersal. Marchalina hellenica (Hemiptera: Marchalinidae), an endemic species in Greece and Turkey, is a major contributor to the annual honey production in its native range. However, in the areas that it invades, lacking natural enemies, it has detrimental effects on pine trees and potentially contributes to tree mortality. Although it was originally reported as thelytokous, males were later reported in Turkey and on several of the islands of Greece. To further disambiguate the exact parthenogenetic reproduction strategy of M. hellenica, we studied the emergence pattern of male individuals in Greece for two consecutive years (2021 and 2022). Furthermore, we examined the genetic variation among 15 geographically distant populations of M. hellenica in Greece using a mitochondrial DNA marker and compared the results with data from Turkey. The findings of this study document the existence of an additional M. hellenica population in its native range that repeatedly produces males, apart from the areas of Greece and Turkey in which they were initially reported, suggesting that males play a major, so far unknown role in the reproduction of this species. The populations in Greece and Turkey exhibited a strong genetic affinity, while human-aided dispersal seems to have obscured the genetic pattern acquired. [ABSTRACT FROM AUTHOR]

Classical biological control, i.e., the introduction of natural enemies from an invasive pest's area of origin, has been proposed repeatedly to control the spotted wing drosophila Drosophila suzukii in the Americas and in Europe. Results from surveys in Asia and laboratory experiments suggest the parasitoid G1 Ganaspis cf. brasiliensis as a suitable biological control agent. To study the host specificity of the parasitoid under semi-field conditions, we conducted large-arena field cage releases. Parasitoids were released into cages at three dates in August 2021 in two regions of Switzerland. Released parasitoids had the choice to parasitize either D. suzukii larvae in fresh fruits (blueberries or elderberries) or the non-target native species D. melanogaster in decomposing fruits. The results were unequivocal in that apparent parasitism of D. suzukii larvae feeding in fresh fruits was on average 15%, whereas only one parasitoid emerged from D. melanogaster feeding on decomposing fruits (0.02% parasitism). Thus, the results support findings from previous laboratory experiments that G1 G. cf. brasiliensis is highly specific to D. suzukii larvae feeding in fresh fruits and parasitism of the closely related D. melanogaster feeding on decomposing fruits is very rare. Because in its invaded range, D. suzukii is the only Drosophila species that can attack and develop in undamaged fresh fruits, we conclude that open field releases of the parasitoid G1 G. cf. brasiliensis should not pose significant risks to non-targets. [ABSTRACT FROM AUTHOR]

Invasive alien species have environmental, economic and social impacts, disproportionally threatening livelihood and food security of smallholder farmers in low- and medium-income countries. Fall armyworm (FAW) (Spodoptera frugiperda), an invasive insect pest from the Americas, causes considerable losses on maize to smallholder farmers in Africa since 2016. The increased use of pesticides to control FAW in Africa raises concerns for health and environmental risks resulting in a growing interest in research on biological control options for smallholder farmers. In order to evaluate the occurrence of local natural enemies attacking FAW, we collected on a weekly basis FAW eggs and larvae during a maize crop cycle in the rainy season of 2018–2019 at four locations in the Lusaka and Central provinces in Zambia. A total of 4373 larvae and 162 egg masses were collected. For each location and date of collection, crop stage, the number of plants checked and amount of damage were recorded to analyse which factors best explain the occurrence of the natural enemy species on maize. Overall parasitism rates from local natural enemies at each location varied between 8.45% and 33.11%. We identified 12 different egg-larval, larval and larval-pupal parasitoid species. Location, maize growth stage, pest density and larval stage significantly affected parasitoid species occurrence. Our findings indicate that there is potential for increasing local populations of natural enemies of FAW through conservation biological control programmes and develop safe and practical control methods for smallholder farmers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Leucopis hennigrata is a promising candidate for biological control of Adelges nordmannianae in Northern Europe. • L. hennigrata is a key predator of Ad. nordmannianae in Western Asia and Central Europe. • Under laboratory conditions larvae of L. hennigrata killed 57–117 eggs in 24 h. • Adult L. hennigrata oviposited on various non-target species, but rarely completed development. • Leucopis hennigrata was not found from non-target adelgids or aphids in the field. The silver fly Leucopis hennigrata McAlpine is a predator of the silver fir wooly adelgid, Adelges nordmannianae (Eckstein), a pest in the European production of Christmas trees. While the fly is known to be a common native predator of the adelgid in Georgia, Turkey, and central Europe, it is absent from northern Europe, where the Christmas tree production is an important industry. Therefore, L. hennigrata has been suggested as a classical biological control agent of Ad. nordmannianae in northern Europe. Here, we evaluated the fly's suitability as a classical biological control agent in terms of (1) differences between Asian and European populations, (2) its abundance relative to other predators of Ad. nordmannianae , (3) larval feeding efficacy, as well as (4) the physiological and (5) ecological prey preference of the fly. The results showed that despite genetic divergence between Western Asian and Central European populations, L. hennigrata is a dominant natural enemy of Ad. nordmannianae in Switzerland, the Pontic mountains in northern Turkey, and in the Greater and Lesser Caucasus mountains. Larvae of L. hennigrata killed on average 57–117 eggs in 24 h, depending on their size, the number of eggs offered to them, and possibly some environmental factors. In no-choice tests, adult flies oviposited on twigs containing different non-target adelgid, aphid, and scale insect species. Larvae of L. hennigrata were observed to feed on several of them. However, only the non-target species Mindarus abietinus Koch supported development of a single specimen to the adult stage. During field surveys in Switzerland and Georgia, L. hennigrata was never found on any sampled non-target species. Based on our findings, we conclude that L. hennigrata is a suitable classical biological control agent because it (1) is already present in countries that neighbor northern Europe, (2) is a dominant natural enemy of the pest in Switzerland, (3) is an efficient predator of the pest's eggs, and (4) seems to be specific to Ad. nordmannianae in its ecological range. [ABSTRACT FROM AUTHOR]

Simple Summary: The silver fly Neoleucopis kartliana Tanasijtshuk (Diptera, Chamaemyiidae) is the most abundant predator of the giant pine scale (GPS), Marchalina hellenica (Hemiptera, Margarodidae), and is considered a major factor in controlling GPS populations in Greece and Turkey. GPS has recently been detected in Australia. While generally not harmful to trees in its area of origin, GPS has a detrimental impact on pine trees in Australia and, therefore, needs to be controlled. As part of an evaluation of the silver fly for importation to Australia where it may be used as a biological control agent against GPS, we studied several aspects of the fly's life history, namely its seasonal occurrence and number of generations per year (phenology), its acceptance of artificial food sources as adult flies, and the number of eggs females produce over their lifetime. We found that the fly has three generations per year and feeds on all life stages of GPS (eggs, nymphs, and adults). Adults readily feed on a mixture of sugar and dry yeast, and females emerge with no or few eggs and develop more as they age. Neoleucopis kartliana Tanasijtshuk (Diptera, Chamaemyiidae) is the most abundant predator of the giant pine scale (GPS), Marchalina hellenica (Hemiptera, Margarodidae) in Greece. GPS is native to Greece and Turkey, where it is not considered a pest of Pinus spp., but a valuable resource for pine honey production. However, its introduction to new areas leads to high population densities of the scale, linked to declines in tree health and insect biodiversity. To assess the potential use of N. kartliana for a classical biological control program in Australia, we studied selected life-history traits of the silver fly, namely its phenology in northern Greece, feeding preferences of adult flies on artificial food sources, and potential fecundity of female flies. The silver fly was present in every site in northern Greece studied and was found to have at least three generations per year in this area. The fly's overall sex ratio was 1:1, and adult females emerged with no or few mature eggs in their ovaries, but egg production was exponential until at least the eighth day after emergence. These findings increase our knowledge about the biology of N. kartliana and aided in the evaluation of the silver fly as a classical biological control agent against invasive GPS in Australia. [ABSTRACT FROM AUTHOR]

Simple Summary: In West Africa, termites are commonly used as protein feed for poultry by smallholder farmers who trap them by placing containers filled with organic matters on termite tracks. The objective of this study conducted in Burkina Faso was to test and improve the technique to increase the availability of termites for traditional poultry farmers. The study focused on termites of the genus Macrotermes and found that the quantity of termites trapped varied with the containers' types, substrates placed in the container, habitats, harvesting times, duration of trap deposition, and season. These results allow to provide information to farmers on how to optimize the trapping of Macrotermes species and increase the quantity of termites available as protein source for their poultry. This study aimed to promote the use of termites as feed in traditional poultry farming by developing sustainable and inexpensive termite trapping techniques. Various tests were carried out in Burkina Faso to improve the traditional technique of trapping termites of the genus Macrotermes using a reversed container filled with organic matters. We studied the effect of containers' types, substrates, habitats, harvesting times, duration of trap deposition, and season on the quantity of termites trapped. Calabashes and terra cotta pots trapped more termites than iron boxes, but calabashes were quickly destroyed by termites. The quantity of termites harvested increased proportionally with the volume of the pot and was higher in a cultivated habitat than in a forest, despite the higher number of termite mounds in the forest. The quantity of termites harvested was lowest in the cold-dry season and highest during the rainy season, however, sizeable amounts of termites were collected throughout the year. Among six substrates and mixtures of substrates tested, maize cobs trapped the highest number of termites and cow dung the lowest. The best time of harvest varied among seasons and, if substrates are abundant, it is more efficient to empty the containers on a daily basis. [ABSTRACT FROM AUTHOR]

Simple Summary: The fall armyworm (FAW) is a serious threat to maize production in Africa following its outbreak in 2016. Fortunately, some beneficial insects that could control FAW are already present in Africa, including Telenomus remus which parasitizes FAW eggs. Telenomus remus has been used in South America for biological control of FAW for several decades. Though T. remus is already present in Africa, little is known about its potential to be used for augmentative biological control of FAW under ecological conditions and agricultural systems in Africa. This study contributed to addressing this knowledge gap by conducting replicated field release trials of T. remus for FAW control in large maize plots in Ghana. In the major and minor rainy seasons, T. remus parasitized up to 33% and 100% of FAW egg masses, respectively, in the release plots. However, similar effectiveness of T. remus was recorded in non-treated control and farmers' plots located at 150–400 m distance from release plots, indicating high dispersion of the parasitoid. A single application of Emamectin benzoate did not significantly affect the parasitism rates of T. remus, and could be considered in IPM strategies against FAW. In response to the threat caused by the fall armyworm to African maize farmers, we conducted a series of field release studies with the egg parasitoid Telenomus remus in Ghana. Three releases of ≈15,000 individuals each were conducted in maize plots of 0.5 ha each in the major and minor rainy seasons of 2020, and compared to no-release control plots as well as to farmer-managed plots with chemical pest control. No egg mass parasitism was observed directly before the first field release. Egg mass parasitism reached 33% in the T. remus release plot in the major rainy season, while 72–100% of egg masses were parasitized in the minor rainy season, during which pest densities were much lower. However, no significant difference in egg mass parasitism was found among the T. remus release plots, the no-release control plots and the farmer-managed plots. Similarly, no significant decrease in larval numbers or plant damage was found in the T. remus release fields compared to the no-release plots, while lower leaf and tassel damage was observed in farmer-managed plots. Larval parasitism due to other parasitoids reached 18–42% in the major rainy season but was significantly lower in the minor rainy season, with no significant differences among treatments. We did not observe significant differences in cob damage or yield among the three treatments. However, the lack of any significant differences between the release and no-release plots, which may be attributed to parasitoid dispersal during the five weeks of observation, would require further studies to confirm. Interestingly, a single application of Emamectin benzoate did not significantly affect the parasitism rates of T. remus and, thus, merits further investigation in the context of developing IPM strategies against FAW. [ABSTRACT FROM AUTHOR]