Cabi

Abstract Background: Telenomus remus (Hymenoptera: Platygastridae) is a promising egg parasitoid for the biocontrol of Spodoptera frugiperda (Lepidoptera: Noctuidae), owing to its high fecundity, ability to parasitize multi-layered egg masses, and suitability for mass rearing. However, the short shelf life of mass-reared T. remus limits its practical application. Cold storage may be a viable solution to stabilize production and supply. Methods: Two experiments were conducted. In the first experiment, viable and UV-treated S. frugiperda eggs were stored at 4, 7, and 10°C for 7 and 14 days, followed by evaluation of their suitability for T. remus parasitism. In the second experiment, eggs parasitized by T. remus (1, 3, 5, and 7 days post-parasitism) were stored under varying temperatures (4, 7, and 10°C) for 7 and 14 days, and the parasitoid emergence rates were recorded to assess stage-specific cold tolerance. Results: UV treatment of eggs significantly reduced the emergence rate of T. remus. Viable S. frugiperda eggs remained suitable hosts for parasitoid reproduction after 7 days of storage at 4°C and 7°C. Cold storage significantly affected parasitoid survival across developmental stages, and 7 days post-parasitism eggs exhibited high adult emergence rates when stored at 10°C for up to 14 days. Conclusions: The results demonstrate that eggs at 7 days post-parasitism can be stored at 10°C for up to 14 days without significant loss of viability. This study presents a potential method for the large-scale production of T. remus , enabling the parasitoids to be supplied to regions severely affected by S. frugiperda .

This study describes two new species of Glyptothorax from the Mekong River drainage in Cambodia and Laos. Glyptothorax carnatus can be distinguished from Mekong congeners by its deep body relative to the caudal peduncle (caudal peduncle depth 2.8-3.6 times in body depth at dorsal-fin origin vs. 1.9-3.0) and combination of characters in color pattern, thoracic adhesive apparatus (TAA) morphology, nuchal plate shape, and morphometry. Glyptothorax rhadinus can be distinguished from Mekong congeners by its very slender TAA (width 1.9-2.2 times in its length vs. 1.1-1.9) and a combination of characters in color pattern, thoracic adhesive apparatus (TAA) morphology, nuchal plate shape, and morphometry. Both species have been previously confused with G. fuscus and G. lampris, and comparisons with these two species are provided.

Prosopis trees have intentionally been introduced to eastern Africa to provide a suite of benefits. The trees have subsequently become invasive, resulting in detrimental impacts on ecosystems and people’s livelihoods. Their management is therefore complex, with no apparent simple solutions being available. Addressing this will require integrated interdisciplinary research approaches involving ecologists, economists and social scientists, as well as close collaboration with the potential end-users of research findings. This book describes how these problems were addressed in a 8-year research initiative, the Woody Weeds project, and a three-year implementation project, the Woody Weeds + project, which sought to integrate findings from different disciplines to scale these up to appropriate spatial resolutions, and to involve potential end-users at all stages. This chapter outlines the intention of the book to draw together scattered studies into a single, open-access volume that should be useful to researchers and managers alike.

Abstract Background Culturing of fungi is labor-intensive and reveals limited diversity, while high-throughput sequencing of barcodes (i.e., metabarcoding) enables simultaneous detection of fungi from multiple environmental samples. Short-read metabarcoding, using for example Illumina platforms, provides high sequencing depths but results in many unidentified taxa. Long-read sequencing may improve species and genus assignments but encompasses lower sequencing depth, limiting diversity coverage. In this study, we assessed fungi in seeds of eleven angiosperm and gymnosperm tree species using traditional culturing, Illumina short-read metabarcoding, and Oxford Nanopore Technologies long-read metabarcoding. We focused on seed-borne fungi as understanding their diversity and potential impacts on seedlings is crucial for securing plant health. We compared 1) the number and identity of fungal genera and species between metabarcoding approaches and traditional culturing and 2) fungal alpha- and beta-diversity between metabarcoding methods, considering different hosts and fungal lifestyles.Results In both short- and long-read metabarcoding datasets, similar numbers of fungal reads and operational taxonomic units were assigned to comparable numbers of fungal genera and species. About one-third of the identified genera were plant pathogens, followed by saprotrophs and endophytes. Culturing overall revealed fewer fungal genera, while most of the fungal reads in short-read metabarcoding datasets stemmed from cultured taxa. Long-read metabarcoding revealed lower per-sample diversity than short-read metabarcoding and distinct fungal communities. Host-dependent patterns in alpha- and beta-diversity were observed across all methods, with angiosperms harboring more fungal taxa than gymnosperms, and distinct community structuring across host tree groups and species, although the differences were stronger in short-read than long-read metabarcoding datasets.Conclusions Illumina and Oxford Nanopore Technologies metabarcoding captured similar host-dependent diversity patterns despite observed differences in numbers and composition of fungi. Short-read metabarcoding might be optimal for fungal biodiversity studies due to higher sequencing depths and resultant breadth of diversity. As error rates decrease, reference databases expand, and throughput improves, long-read metabarcoding may become a strong candidate for future diagnostic studies of fungi. Traditional culturing captures most of the fungi from short-read metabarcoding and remains valuable for obtaining isolates for further research.

Non-native invasive arthropod species threaten biodiversity and food security worldwide, resulting in substantial economic, environmental, social and cultural costs. Classical biological control (CBC) is regarded as a cost-effective component of integrated pest management programmes to manage invasive arthropod pests sustainably. However, CBC programmes are traditionally conducted once a pest has established in a new environment, and invariably all research needed to achieve approval to release a biological control agent can take several years. During that time, adverse impacts of the pest accelerate. A pre-emptive biocontrol approach will provide the opportunity to develop CBC for invasive pests before they arrive in the country at risk of introduction and therefore enhance preparedness. A critical aspect of this approach is that risk assessment is carried out in advance of the arrival of the pest. Implementing pre-emptive biocontrol risk assessment means that natural enemies can be selected, screened in containment or abroad and potentially pre-approved prior to a pest establishing in the country at risk, thus improving CBC effectiveness. However, such an approach may not always be feasible. This contribution defines the fundamental prerequisites, principles, and objectives of pre-emptive biocontrol risk assessment. A set of guidelines and a decision framework were developed, which can be used to assess the feasibility of conducting a pre-emptive risk assessment for candidate biological control agents against high-risk arthropod pests.

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.

Woody species have been introduced in many parts of the world to provide economic benefits, but some of those species are now among the worst invaders, causing widespread economic and environmental damage. Management of woody species to restore original ecosystem services, such as biodiverse grassland that can provide fodder and sequester carbon, are needed to limit the impacts of alien species. However, the best management methods, i.e., the most economically efficient and effective way to remove trees and the most effective way to restore or rehabilitate the cleared land, are not developed for many species. In Eastern Africa, prosopis (Prosopis julifora) has invaded large areas of savanna and grassland, thereby affecting, among other things, fodder and water for livestock, access to dry season grazing lands and ultimately pastoral livelihoods. We tested three prosopis treatments (manual uprooting and cut stump and basal bark herbicide application) in combination with three incremental restoration interventions (divots, divots + mulching, divots + mulching + grass seed sowing). The three-year study was replicated in Ethiopia (Afar National Regional State), Kenya (Baringo county) and Tanzania (Moshi district). Prosopis survival and vegetation development, both diversity and biomass, were recorded. The prosopis treatments were all highly effective (between 85 and 100% tree mortality in almost all cases), but the two treatments that involved the complete removal of the aboveground biomass (manual and cut stump) yielded a more productive and more diverse vegetation than the treatment that killed the trees standing (basal bark). Compared to the effect of prosopis removal, the effect of restoration interventions on vegetation composition was small, indicating that most species re-established from the soil seed bank. The results show that it is possible to restore land previously invaded by prosopis. Despite the different rates of vegetation establishment and variation in species composition, the restoration interventions resulted in vegetation that in some cases contained a substantial fraction of perennial grasses. The method chosen to control prosopis depends on the availability of resources, including herbicides, and the need to remove rootstocks if the intention is to plant crops.

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.

The impacts of invasive alien plant species on native plants are generally well documented, but little is known about the mechanisms underlying their impacts on crop growth. A better understanding of immediate as well as legacy effects and of direct and indirect impacts of invasive alien plant species is essential for an improved management of invaded cropland. We investigated how Lantana camara impacts the growth of two subsistence crops (maize and cassava) through competition for resources, allelopathy and the indirect plant-plant interactions. We carried out two pot experiments using soils from invaded abandoned, invaded cultivated and non-invaded cultivated crop fields. In the first experiment maize and cassava were grown alone or together with L. camara and half of the pots were treated with activated carbon to suppress allelochemicals. The effect of the soil microbial community on L. camara-crop interactions was assessed in a second experiment using autoclaved soil with 5% of soil from the three soil types. We found that L. camara reduced the growth of maize by 29%, but cassava was not affected. We did not find evidence of allelopathic effects of L. camara. Inoculation of autoclaved soil with microorganisms from all soil types increased biomass of cassava and reduced the growth of maize. Because L. camara only caused impacts when growing simultaneously with maize, the results suggest that removal of L. camara will immediately mitigate its negative impacts on maize.

Simple SummaryThe brown marmorated stink bug is an invasive true bug that originates in eastern Asia and is considered now one of the most harmful invasive insect pests in North America and Europe. Similar to the many species that produce more than one generation per year, this bug responds to day length: under short-day conditions (which predict the approaching of autumn), adults form a special overwintering (diapause) physiological state, whereas, under long-day conditions (typical for summer), they reproduce. Critical day length is the condition that induces diapause in 50% of adults. This critical day length is usually strongly correlated with the latitude of the population origin. In this study, we compared the critical day lengths of one native (Andong, South Korea) and three invasive (Torino, Italy; Basel, Switzerland; and Sochi, Russia) populations. The critical day lengths of both sexes fell between 14.5 and 15.0 h in the Korean population, and between 15.0 and 15.5 h in the three European populations. The results demonstrate that microevolution was possibly ‘too slow to keep up’ with the rapid spread of the invader across Eurasia. It is expected that in the near future, the critical day length of invasive H. halys populations will gradually change to adapt better to the local conditions.Facultative winter adult diapause in Halyomorpha halys is regulated by a long-day photoperiodic response. Day length also influences nymphal development, which slows down at the critical (near-threshold) day lengths. We compared the photoperiodic responses of one native (Andong, South Korea) and three invasive (Torino, Italy; Basel, Switzerland; and Sochi, Russia) populations in a laboratory common-garden experiment. Nymphs developed and emerging adults were reared at 24 °C in a range of photoperiods with day lengths of 14.0, 14.5, 15.0, 15.5, and 16.0 h. The critical day lengths of the photoperiodic responses of both sexes fell between 14.5 and 15.0 h in the native Korean population and between 15.0 and 15.5 h in three invasive European populations. The differences between the three invasive populations were not significant, despite their distant origins. Moreover, the difference between the Korean and European populations was much smaller than was expected. The microevolution was possibly ‘too slow to keep up’ with the rapid spread of the invader across Eurasia. It is expected that soon the critical day length of the invasive H. halys populations will gradually change to adapt better to local conditions. At present, the critical day length for diapause induction of 15 h 15 min can be used to model the phenology, further spread, and response to climate change for all European populations of the pest.