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1.
Article in English | MEDLINE | ID: mdl-38951369

ABSTRACT

INTRODUCTION: There is a paucity of research investigating disparities in utilization of inpatient therapeutics for COVID-19 by language preference. The primary aim of this study was to assess if the likelihood of treatment with novel COVID-19 therapies differed for patients using a language other than English (LOE) relative to English-speaking patients. METHODS: This was a retrospective observational cohort study of COVID-19 patients hospitalized between March 1, 2020, and June 30, 2022, across 11 hospitals within a single not-for-profit health system. Multivariable relative risks were estimated for the impact of preferred language on the receipt of novel COVID-19 therapies: baricitinib, remdesivir, tocilizumab, and convalescent plasma. RESULTS: This study included 12,510 hospitalized adults with English as the most common preferred language (92.3%) followed by Spanish (3.1%), Somali (1.3%), Russian (0.9%), and Hmong (0.6%). Spanish speakers were more likely to receive any of the novel COVID-19 therapies compared to English speakers (RR 1.45; CI 1.32-1.59). Estimates for Hmong, Somali, Russian, and Other language groups were not statistically significant and closer to the null (aRR range, 0.89-1.12). CONCLUSION: Linguistic patterns in health outcomes expose inherent heterogeneity within racial and ethnic groups. Our study found that Spanish speakers were nearly 1.5 times more likely to receive any of the four novel inpatient COVID-19 therapeutics in comparison to English speakers. Future research is needed to explore the reasons for the heterogeneous findings including temporal influence, cultural factors, informed consent comprehension, and therapeutic hesitancy in all groups.

2.
Microb Ecol ; 87(1): 81, 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38829379

ABSTRACT

Koinobiont endoparasitoids regulate the physiology of their hosts through altering host immuno-metabolic responses, processes which function in tandem to shape the composition of the microbiota of these hosts. Here, we employed 16S rRNA and ITS amplicon sequencing to investigate whether parasitization by the parasitoid wasps, Diachasmimorpha longicaudata (Ashmaed) (Hymenoptera: Braconidae) and Psyttalia cosyrae (Wilkinson) (Hymenoptera: Braconidae), induces gut dysbiosis and differentially alter the gut microbial (bacteria and fungi) communities of an important horticultural pest, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). We further investigated the composition of bacterial communities of adult D. longicaudata and P. cosyrae to ascertain whether the adult parasitoids and parasitized host larvae share microbial taxa through transmission. We demonstrated that parasitism by D. longicaudata induced significant gut perturbations, resulting in the colonization and increased relative abundance of pathogenic gut bacteria. Some pathogenic bacteria like Stenotrophomonas and Morganella were detected in both the guts of D. longicaudata-parasitized B. dorsalis larvae and adult D. longicaudata wasps, suggesting a horizontal transfer of microbes from the parasitoid to the host. The bacterial community of P. cosyrae adult wasps was dominated by Arsenophonus nasoniae, whereas that of D. longicaudata adults was dominated by Paucibater spp. and Pseudomonas spp. Parasitization by either parasitoid wasp was associated with an overall reduction in fungal diversity and evenness. These findings indicate that unlike P. cosyrae which is avirulent to B. dorsalis, parasitization by D. longicaudata induces shifts in the gut bacteriome of B. dorsalis larvae to a pathobiont-dominated community. This mechanism possibly enhances its virulence against the pest, further supporting its candidacy as an effective biocontrol agent of this frugivorous tephritid fruit fly pest.


Subject(s)
Bacteria , Gastrointestinal Microbiome , Larva , RNA, Ribosomal, 16S , Tephritidae , Wasps , Animals , Tephritidae/microbiology , Tephritidae/parasitology , Wasps/microbiology , Wasps/physiology , Bacteria/genetics , Bacteria/classification , Bacteria/isolation & purification , Larva/microbiology , Larva/parasitology , Larva/growth & development , RNA, Ribosomal, 16S/genetics , Fungi/genetics , Fungi/physiology , Host-Parasite Interactions , Microbiota , Dysbiosis/microbiology , Dysbiosis/parasitology
4.
Heliyon ; 10(9): e30068, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38707327

ABSTRACT

Before the introduction of Bactrocera dorsalis (Hendel) to sub-Saharan Africa, Ceratitis cosyra (Walker) was economically the most important pest in mango farming. Its native natural enemy, the solitary parasitoid Psyttalia cosyrae (Wilkinson), played a crucial role in C. cosyra bio-control, later complemented by the exotic parasitoids Diachasmimorpha longicaudata (Ashmead) and Fopius arisanus (Sonan) among Integrated Pest Management (IPM) systems. To understand the in situ mango-C. cosyra-parasitoid tritrophic interaction, we assessed the responses of the fruit fly and the three parasitoids to headspace volatiles from various mango conditions. These conditions included non-infested mature unripe mangoes, C. cosyra-infested mangoes, 7th- and 9th-day post-infestation mangoes, non-infested ripe mangoes of three varieties (Kent, Apple, and Haden), and clean air (blank). We also compared the fruit fly's performance in the mango varieties and identified the chemical profiles of mango headspace volatiles. Ceratitis cosyra was attracted to both infested and non-infested mangoes (66-84 % of responsive C. cosyra) and showed superior performance in Kent mango (72.1 % of the 287 puparia recovered) compared to Apple and Haden varieties. Fopius arisanus displayed a stronger attraction to the volatiles of C. cosyra-infested mangoes (68-70 %), while P. cosyrae and D. longicaudata were significantly attracted to the 9th-day post-infestation mangoes (68-78 %) compared to non-infested mango volatiles. Gas chromatography-mass spectroscopy showed substantial quantitative and qualitative differences in volatile profiles among mango treatments. Esters predominated in non-infested ripe, 7th- and 9th-day post-infestation mangoes, while monoterpenes and sesquiterpenes were most dominant in the other treatments. The in situ experiments underscored varying preferences of the species for mango headspace volatiles and their subsequent treatments. These results provide valuable insights for further exploration, specifically in identifying the key volatiles responsible for species responses, to facilitate the development of applicable selective semiochemicals for managing species of African fruit fly.

5.
Sci Rep ; 14(1): 5045, 2024 02 29.
Article in English | MEDLINE | ID: mdl-38424443

ABSTRACT

The future of the food system on the planet is increasingly facing uncertainties that are attributable to population growth and a surge in demand for nutritious food. Traditional agricultural practices are poised to place strain on production, as well as natural resources and ecosystem services provided, particularly under a changing climate. Given their remarkable attributes, including a low environmental footprint, high food conversion ratio, rapid growth and nutritional values, edible insects can play a vital role in the global food system. Nonetheless, substantial knowledge gaps persist regarding their diversity, global distribution, and shared characteristics across regions, potentially impeding effective scaling and access to edible insects. Therefore, we compiled and analysed the fragmented database on edible insects and identified potential drivers that elucidate insect consumption, globally, focusing on promoting a sustainable food system. We collated data from various sources, including the literature for a list of edible insect species, the Global Biodiversity Information Facility and iNaturalist for the geographical presence of edible insects, the Copernicus Land Service library for Global Land Cover, and FAOSTAT for population, income, and nutritional security parameters. Subsequently, we performed a series of analytics at the country, regional and continental levels. Our study identifies 2205 insect species, consumed across 128 countries globally. Among continents, Asia has the highest number of edible insects (932 species), followed by North America (mainly Mexico) and Africa. The countries with the highest consumption of insects are Mexico (450 species), Thailand (272 species), India (262 species), DRC (255 species), China (235 species), Brazil (140 species), Japan (123 species), and Cameroon (100 species). Our study also revealed some common and specific practices related to edible insect access and utilisation among countries and regions. Although insect consumption is often rooted in cultural practices, it exhibits correlations with land cover, the geographical presence of potentially edible insects, the size of a country's population, and income levels. The practice of eating insects is linked to the culture of people in Africa, Asia, and Latin America, while increased consciousness and the need for food sustainability are driving most of the European countries to evaluate eating insects. Therefore, edible insects are becoming an increasingly significant part of the future of planetary food systems. Therefore, more proactive efforts are required to promote them for their effective contribution to achieving sustainable food production.


Subject(s)
Edible Insects , Animals , Humans , Ecosystem , Insecta , Allergens , Cameroon , Thailand
6.
Life (Basel) ; 14(2)2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38398690

ABSTRACT

Before the invasion of the fall armyworm (FAW) Spodoptera frugiperda into Africa, smallholder farmers had been using indigenous practices such as applying fish soup to plants to manage stemborer pests. Although farmers have since begun adapting this practice against FAW, no attempt has been made to scientifically evaluate this practice. Therefore, we assessed the efficacy of applying fish soup to maize plants that were artificially infested with FAW under semi-field conditions. Our results showed that foliar damage is inversely correlated with the concentration of a fish soup and sugar solution, with the highest (100%) concentration resulting in the lowest foliar damage and the highest plant recovery. The FAW foliar damage results for maize plants treated with 100%, 50%, 10% fish soup and sugar, and distilled water were 46.3 ± 5.6, 51.1 ± 5.0, 71.6 ± 5.2, and 99.4 ± 0.4%, respectively, whereas plant recovery results from the same treatments were 35.2 ± 3.7, 31.1 ± 5.4, 20.0 ± 4.6, and 0.0 ± 0.0%, respectively. A concentration of fish soup and sugar solution of at least 25.9% was required to achieve the lowest foliar damage of 17.8% and peak plant recovery of 73.6%. Fish soup and sugar solutions attracted a wide range of insects, including potential natural enemies (predators and parasitoids) of FAW, in a dose-dependent manner. Maize plants treated with fish soup and sugar showed higher chlorophyll content and better growth than the control did. Proximate and chemical analysis showed that fish soup contains essential plant growth nutrients (e.g., nitrogen, phosphorus, and calcium). Through GC-MS analyses, we identified 76 volatile organic compounds in fish soup, of which 16 have been reported as insect attractants, highlighting their potential ecological significance. Therefore, the indigenous pest management practices for FAW, such as the use of fish soup, deserve particular attention. These practices could contribute to food security and improve the livelihoods of vulnerable communities. Further field validation studies, economic analyses, product development, and optimisation are therefore required to optimise the use of fish soup based on fish waste.

7.
Article in English | MEDLINE | ID: mdl-38330807

ABSTRACT

The false codling moth (FCM), Thaumatotibia leucotreta, is a major quarantine pest native to Africa. Physical postharvest phytosanitary measures such as cold and heat treatments are championed to control its spread to new regions. However, the molecular changes that T. leucotreta undergoes as it attempts to adjust to its surroundings during the treatments and withstand the extreme temperatures remain largely unknown. The current study employs RNA-seq using the next-generation Illumina HiSeq platform to produce transcriptome profiles for differential gene expression analysis of T. leucotreta larvae under thermal stress. The transcriptome assembly analysis revealed 226,067 transcripts, clustering into 127,018 unigenes. In comparison to the 25 °C treated group, 874, 91, 159, and 754 individual differentially expressed genes (DEGs) co-regulated at -10, 0, 40, and 50 °C, respectively were discovered. Annotation of the DEGs by gene ontology (GO) revealed several genes, previously implicated in low and high-temperature stresses, including heat shock proteins, cytochrome P450, cuticle proteins, odorant binding proteins, and immune system genes. Kyoto Encyclopedia of Genes and Genomics (KEGG) classification analysis revealed that substantive DEGs were those involved in metabolic pathways such as thiamine, purine, folate, and glycerolipid metabolism pathways. The RT-qPCR validation of several significantly up- and down-regulated DEGs showed congruence between RNA-seq and qPCR data. This baseline study lays a foundation for future research into the molecular mechanisms underlying T. leucotreta's cold/heat tolerance by providing a thorough differential gene expression analysis that has identified multiple genes that may be associated with the insect's ability to withstand cold and heat.


Subject(s)
Gene Expression Profiling , Moths , Transcriptome , Animals , Moths/genetics , Cold Temperature , Insect Proteins/genetics , Hot Temperature , Larva/genetics , Larva/growth & development
8.
Sci Rep ; 13(1): 16477, 2023 09 30.
Article in English | MEDLINE | ID: mdl-37777630

ABSTRACT

Phthorimaea absoluta (Meyrick) (= Tuta absoluta) (Lepidoptera: Gelechiidae), is the most damaging insect pest threatening the production of tomato and other solanaceous vegetables in many countries. In this study, we predicted the risk of establishment and number of generations for P. absoluta in the current and future climatic conditions under two Shared Socioeconomic Pathways (SSP2-4.5 and SSP5-8.5) of the years 2050 and 2070 using insect life cycle modelling (ILCYM) software. We used a temperature-dependent phenology model to project three risk indices viz., establishment risk index (ERI), generation index (GI), and activity index (AI) based on temperature data. The model projected large suitable areas for P. absoluta establishment in the Southern hemisphere under current and future climatic scenarios, compared to the Northern part. However, the risk of P. absoluta is expected to increase in Europe, USA, Southern Africa, and some parts of Asia in the future. Under current conditions, P. absoluta can complete between 6 and 16 generations per year in suitable areas. However, an increase in GI between 1 and 3 per year is projected for most parts of the world in the future, with an increase in AI between 1 and 4. Our results provide information on the risk of establishment of P. absoluta which could guide decision-makers to develop control strategies adapted for specific agro-ecological zones.


Subject(s)
Lepidoptera , Moths , Solanum lycopersicum , Animals , Enterobius , Climate Change , Larva
9.
Pest Manag Sci ; 79(12): 5312-5320, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37605965

ABSTRACT

BACKGROUND: Maize production in Africa is hindered by a myriad of biotic challenges, key among them being invasive and native lepidopteran stemborers. Recent invasion of the continent by fall armyworm, Spodoptera frugiperda, has further exacerbated the situation. Fortunately, Cotesia icipe was found to be very promising against S. frugiperda. However, the co-occurrence and interaction between S. frugiperda and the stemborers (Busseola fusca, Sesamia calamistis, and Chilo partellus) in maize agroecosystem may jeopardize the efficiency of C. icipe as a biocontrol agent of S. frugiperda. This study investigated the performance of C. icipe on S. frugiperda, Spodoptera littoralis and the stemborers. Specifically, the preference and acceptability of C. icipe to the host insects, the physiological suitability of the hosts for its development, and the effect of these hosts on the fitness parameters of the offspring were assessed. RESULTS: Cotesia icipe accepted all the tested hosts, albeit with higher preference for Spodoptera species than for stemborers under multiple-choice tests. Also, the highest parasitism of up to 97% was recorded on S. frugiperda compared with parasitism on the stemborers of 43% in B. fusca. Moreover, physiological suitability and fitness traits (except for per cent female offspring) varied with host species, again being optimal on Spodoptera species. CONCLUSION: Cotesia icipe demonstrated strong potential to control S. frugiperda in maize due to its high affinity for parasitization and developmental success in this host; and despite its non-specific parasitization, the presence of other hosts may not prevent its maximum control of S. frugiperda. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Subject(s)
Hymenoptera , Moths , Female , Animals , Hymenoptera/physiology , Spodoptera , Introduced Species , Zea mays , Larva
10.
J Econ Entomol ; 116(5): 1529-1539, 2023 Oct 10.
Article in English | MEDLINE | ID: mdl-37597612

ABSTRACT

The negative effects of pest infestation on agricultural production cannot be underestimated. There have been several efforts to control these pests, chiefly through the use of synthetic pesticides. However, the continuous use of the chemicals causes pest resistance and resurgence and presents high human and environmental risks. This study examines the economic, health, and environmental impacts of Tuta absoluta (Meyrick 1917), an economically important pest in tomato production, among smallholder farmers in selected counties in Kenya and Uganda. Economic Impact Quotient and gross margin analysis were used on data obtained from a random sample of 316 and 345 tomato growers in Kenya and Uganda, respectively. The results show a significant impact of T. absoluta on tomato production in both countries. On average, the tomato growers earned a gross income of $38,123 and $11,627 in Kenya and Uganda, respectively, with synthetic chemicals for the management of T. absoluta contributing 66-78% of the cost of production. The opportunity cost lost due to forgoing pesticide for management of the pest, and instead replacing it with an integrated pest management package was valued between $8 and $646 in Kenya and $895 in Uganda, respectively, using net present value through the most pessimistic scenario, while benefit-cost ratio was $1 and $5 in Kenya and Uganda, respectively.

11.
Environ Entomol ; 52(3): 416-425, 2023 Jun 16.
Article in English | MEDLINE | ID: mdl-37170880

ABSTRACT

Sustainable production of pumpkin (Cucurbita maxima Duchesne) partly relies on integrated pest management (IPM) and pollination services. A farmer-managed field study was carried out in Yatta and Masinga Sub-Counties of Machakos County, Kenya, to determine the effectiveness of a recommended IPM package and its interaction with stingless bee colonies (Hypotrigona sp.) for pollinator supplementation (PS). The IPM package comprised Lynfield traps with cuelure laced with the organophosphate malathion, sprays of Metarhizium anisopliae (Mechnikoff) Sorokin isolate ICIPE 69, the most widely used fungal biopesticide in sub-Saharan Africa, and protein baits incorporating spinosad. Four treatments-IPM, PS, integrated pest and pollinator management (which combined IPM and PS), and control-were replicated 4 times. The experiment was conducted in 600 m2 farms in 2 normalized difference vegetation index (NDVI) classes during 2 growing seasons (October 2019-March 2020 and March-July 2020). Fruits showing signs of infestation were incubated for emergence, fruit fly trap catches were counted weekly, and physiologically mature fruits were harvested. There was no effect of IPM, PS, and NDVI on yield across seasons. This study revealed no synergistic effect between IPM and PS in suppressing Tephritid fruit fly population densities and damage. Hypotrigona sp. is not an efficient pollinator of pumpkin. Therefore, we recommend testing other African stingless bees in pumpkin production systems for better pollination services and improved yields.


Subject(s)
Cucurbita , Cucurbitaceae , Bees , Animals , Kenya , Pest Control , Pollination/physiology , Dietary Supplements
12.
Biology (Basel) ; 12(2)2023 Feb 09.
Article in English | MEDLINE | ID: mdl-36829551

ABSTRACT

Parasitoids are promising biocontrol agents of the devastating fruit fly, Bactrocera dorsalis. However, parasitoid performance is a function of several factors, including host-associated symbiotic bacteria. Providencia alcalifaciens, Citrobacter freundii, and Lactococcus lactis are among the symbiotic bacteria commonly associated with B. dorsalis, and they influence the eco-physiological functioning of this pest. However, whether these bacteria influence the interaction between this pest and its parasitoids is unknown. This study sought to elucidate the nature of the interaction of the parasitoids, Fopius arisanus, Diachasmimorpha longicaudata, and Psyttlia cosyrae with B. dorsalis as mediated by symbiotic bacteria. Three types of fly lines were used: axenic, symbiotic, and bacteria-mono-associated (Lactococcus lactis, Providencia alcalifaciens, and Citrobacter freundii). The suitable stages of each fly line were exposed to the respective parasitoid species and reared until the emergence of adult flies/parasitoids. Thereafter, data on the emergence and parasitoid fitness traits were recorded. No wasps emerged from the fly lines exposed to P. cosyrae. The highest emergence of F. arisanus and D. longicaudata was recorded in the L. lactis fly lines. The parasitoid progeny from the L. lactis and P. alcalifaciens fly lines had the longest developmental time and the largest body size. Conversely, parasitoid fecundity was significantly lower in the L. lactis lines, whereas the P. alcalifaciens lines significantly improved fecundity. These results elucidate some effects of bacterial symbionts on host-parasitoid interactions and their potential in enhancing parasitoid-oriented management strategies against B. dorsalis.

13.
Pest Manag Sci ; 79(4): 1585-1592, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36533692

ABSTRACT

BACKGROUND: Tephritid fruit flies are a major constraint to the global production of horticultural crops. In Africa, an array of native and alien invasive fruit fly species represents a key challenge to the horticultural industry. In an effort to develop a safer management tool for these pests, we previously identified glutathione (GSH) and glutamic acid (GA), as the host marking pheromones (HMPs) of Ceratitis cosyra and Ceratitis rosa, respectively. Here, we report on the effectiveness of these compounds (GSH and GA) in reducing natural fruit fly population infestations in mango orchards. Mango trees at two different agroecological zones in Kenya were sprayed with HMPs, and the fruits sampled periodically and assessed for fruit fly emergence. Fruit fly emergence data were compared to two controls, the positive control using spot spraying of food bait (SS), and the negative control using water (W). RESULTS: The two HMPs and SS substantially decreased fruit fly emergence from the sampled mangoes. GSH and GA treated mangoes showed reduced C. cosyra and C. rosa infestation by ~70-75% relative to control (W), and with variation noted in the pheromone applied and the recovered fruit fly species. The adult emergence in pheromone-treated plants compared favorably with the positive control SS. However, the HMPs had little impact on reducing Bactrocera dorsalis infestation of mangoes. CONCLUSION: The decrease in fruit fly emergence in sampled mango fruits from HMP treated trees corroborate previous laboratory results and support the prospect of using HMPs in the management of African fruit fly species. © 2022 Society of Chemical Industry.


Subject(s)
Mangifera , Tephritidae , Animals , Glutamic Acid , Kenya , Pheromones , Drosophila , Glutathione
14.
BMC Med Inform Decis Mak ; 22(1): 326, 2022 12 08.
Article in English | MEDLINE | ID: mdl-36482433

ABSTRACT

BACKGROUND: Breast cancer (BC) is an important reason for mortality rates in Somalian women. In Somalia, many women are late in applying to the hospital for the diagnosis of BC. Breast self-examination (BSE) is considered an important early detection method for BC in encouraging women to learn to practice BSE, especially for women in developing countries. This study purposed to determine knowledge, and belief of BC and BSE and BSE practice among women in Mogadishu, Somalia using the champion health belief model (CHBM). METHODS: This cross-sectional study was conducted on 413 women who were between 18 and 49 years of age. The data were collected by using sociodemographic variables (age, marital status, education level, income status), Champion's Health Belief Model Scale (CHBMS), and an introductory questionnaire with questions about BC and BSE and between October 2020 and January 2021 in Mogadishu, Somalia. Further descriptive statistics, the Mann-Whitney U test, and Kruskal-Wallis analysis test were used to assess data that were not normally distributed. RESULTS: Average age of participants was 22 ± 11.21 years. Only 35.4% of participants had information about BC, 37.8% had heard about BSE before, 25.2% knew BSE, and only 17.2% had done it. Income status, marital status, and age of first birth family were significantly associated with perceived sensitivity, health motivation, convenience, perceived benefits, and self-efficacy for BSE. Overall, the total scores of CHBMS were significantly higher among those who had heard and knowledge about BSE and practiced clinical breast examination (CBE). For the sub-dimensions of perceived sensitivity, health motivation, perceived benefits, barrier, and self-efficacy BSE with hearing about BSE, practicing BSE, knowing to practice BSE, knowing early detection methods of BC and practice CBE significant differences were observed (P < 0.005). CONCLUSION: This study showed that BSE practice among Somalian women was very low, and they don't have sufficient knowledge about BSE and BC. Furthermore, this study revealed that many CHBMS significantly related to BSE practice in Somalian women, suggesting that BSE health education programs with CHBMS.


Subject(s)
Breast Neoplasms , Breast Self-Examination , Female , Humans , Child , Adolescent , Young Adult , Adult , Cross-Sectional Studies , Breast Neoplasms/diagnosis , Health Education
15.
Insects ; 13(11)2022 Nov 13.
Article in English | MEDLINE | ID: mdl-36421948

ABSTRACT

Bactrocera dorsalis and several Africa-native Ceratitis species are serious constraints to fruit production in sub-Saharan Africa. A long-term trapping and fruit collection study was conducted (2011-2016) in two contrasting agro-ecological zones (AEZs) of Cameroon to determine fruit fly species composition, seasonality, attraction to various lures and baits, and fruit infestation levels. Ten tephritid species from genera Bactrocera, Ceratitis, Dacus, and Perilampsis were captured in traps. Bactrocera dorsalis was the most dominant of the trapped species and persisted throughout the year, with peak populations in May-June. Ceratitis spp. were less abundant than B. dorsalis, with Ceratitis anonae dominating in the western highland zone and Ceratitis cosyra in the humid forest zone. Methyl eugenol and terpinyl acetate captured more B. dorsalis and Ceratitis spp., respectively than Torula yeast. The latter was the most effective food bait on all tephritid species compared with BioLure and Mazoferm. Bactrocera dorsalis was the dominant species emerging from incubated fruits, particularly mango, guava, and wild mango. Four plant species-I. wombolu, Dacryodes edulis, Voacanga Africana and Trichoscypha abut-were new host records for B. dorsalis. This study is the first long-duration and comprehensive assessment of frugivorous tephritid species composition, fruit infestations, and seasonality in Central Africa.

16.
Insects ; 13(10)2022 Sep 21.
Article in English | MEDLINE | ID: mdl-36292807

ABSTRACT

In the laboratory, the pathogenicity of thirteen isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and two isolates of Beauveria bassiana (Balsamo) Vuillemin against the melon fly Zeugodacus cucurbitae (Coquillett) were assessed by exposing adults to 0.3 g of dry conidia (~3 × 109 conidia) of each isolate for 5 min and monitoring mortality for up to 5 days. Compatibility with a male pheromone, cuelure, (4-(p-acetoxyphenyl)-2-butanone), was determined by testing conidial germination and germ tube growth of the most promising isolate, M. anisopliae ICIPE 69, in the presence of cuelure at different temperatures. For horizontal transmission, the flies were separated by sex, separately exposed to M. anisopliae ICIPE 69, and subsequently mixed with non-exposed flies from the other sex. The most pathogenic isolates were M. anisopliae ICIPE 69, 18, and 30, causing mortalities of 94, 87, and 81%, with 5 days post-exposure, respectively. Metarhizium anisopliae ICIPE 69 caused the highest pupal mortality of 74%, with 15 days post-exposure. Horizontal transmission of M. anisopliae ICIPE 69 among male and female Z. cucurbitae was confirmed by 59 and 67% mortality after exposure to infected donor males and females, respectively. Metarhizium anisopliae ICIPE 69 affected the oviposition, but not hatchability, of infected Z. cucurbitae females. Metarhizium anisopliae ICIPE 69 is, therefore, a potential isolate for biopesticide development for Z. cucurbitae management in cucurbit production systems.

17.
Front Physiol ; 13: 945370, 2022.
Article in English | MEDLINE | ID: mdl-36091407

ABSTRACT

The oriental fruit fly, Bactrocera dorsalis (Hendel), and marula fruit fly, Ceratitis cosyra (Walker), are major fruit-infesting tephritids across sub-Saharan Africa. Biological control of these pests using parasitic wasps has been widely adopted but with varying levels of success. Most studies investigating host-parasitoid models have focused on functional and evolutionary aspects leaving a knowledge gap about the physiological mechanisms underpinning the efficacy of parasitoids as biocontrol agents of tephritids. To better understand these physiological mechanisms, we investigated changes in the cellular immune responses of C. cosyra and B. dorsalis when exposed to the parasitic wasps, Diachasmimorpha longicaudata (Ashmaed) and Psyttalia cosyrae (Wilkinson). We found that B. dorsalis was more resistant to parasitisation, had a higher hemocyte count, and encapsulated more parasitoid eggs compared to C. cosyra, achieving up to 100% encapsulation when exposed to P. cosyrae. Exposing B. dorsalis to either parasitoid species induced the formation of a rare cell type, the giant multinucleated hemocyte, which was not observed in C. cosyra. Furthermore, compared to P. cosyrae-parasitized larvae, those of both host species parasitized by D. longicaudata had lower encapsulation rates, hemocyte counts and spreading abilities and yielded a higher number of parasitoid progeny with the highest parasitoid emergence (72.13%) recorded in C. cosyra. These results demonstrate that cellular immune responses are central to host-parasitoid interaction in tephritid fruit flies and further suggest that D. longicaudata presents greater potential as a biocontrol agent of B. dorsalis and C. cosyra in horticultural cropping systems.

18.
Biology (Basel) ; 11(9)2022 Aug 28.
Article in English | MEDLINE | ID: mdl-36138759

ABSTRACT

The South American tomato pinworm, Tuta absoluta, causes up to 100% tomato crop losses. As Tuta absoluta is non-native to African agroecologies and lacks efficient resident natural enemies, the microgastrine koinobiont solitary oligophagous larval endoparasitoid, Dolichogenidea gelechiidivoris (Marsh) (Syn.: Apanteles gelechiidivoris Marsh) (Hymenoptera: Braconidae) was released for classical biological control. This study elucidates the current and future spatio-temporal performance of D. gelechiidivoris against T. absoluta in tomato cropping systems using a fuzzy logic modelling approach. Specifically, the study considers the presence of the host and the host crop, as well as the parasitoid reproductive capacity, as key variables. Results show that the fuzzy algorithm predicted the performance of the parasitoid (in terms of net reproductive rate (R0)), with a low root mean square error (RMSE) value (<0.90) and a considerably high R2 coefficient (=0.98), accurately predicting the parasitoid performance over time and space. Under the current climatic scenario, the parasitoid is predicted to perform well in all regions throughout the year, except for the coastal region. Under the future climatic scenario, the performance of the parasitoid is projected to improve in all regions throughout the year. Overall, the model sheds light on the varying performance of the parasitoid across different regions of Kenya, and in different seasons, under both current and future climatic scenarios.

19.
Biology (Basel) ; 11(9)2022 Sep 06.
Article in English | MEDLINE | ID: mdl-36138804

ABSTRACT

The Integrated Pest Management (IPM) approach have been widely promoted and used for the management of native and invasive pests, while the use of various components of the IPM can have a synergetic, additive, or antagonistic effect on each other; this study evaluated the susceptibility of Dolichogenidea gelechiidivoris (Marsh) (Hymenoptera: Braconidae), to the Metarhizium anisopliae (Metschnikoff) ICIPE 20 through direct and indirect infection approaches. The effect of fungus on parasitoid longevity, survival of parasitized-larvae, preference of the parasitoid to fungal treated and untreated larvae, and percent parasitism of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under different infection scenarios were assessed. The direct application of dry conidia to the parasitoid prior to exposure to the host, reduced D. gelechiidivoris longevity, though the infected female wasps still yielded high parasitism (over 70%). Infecting the parasitized larvae at different ages led to a respective reduction of parasitoid emergence by 35% and 23% for infection at 1 and 5 days post-parasitisation. Exposure of healthy-D. gelechiidivoris adults to a plant-sprayed with fungus did not affect their longevity, and no discriminatory host selection was observed. The highest mortality (~80%) of T. absoluta was achieved when D. gelechiidivoris and M. anisopliae ICIPE 20 were used in combination, indicating an additive impact on the target pest; however, field validation can shed more light on this outcome.

20.
PLoS One ; 17(7): e0271241, 2022.
Article in English | MEDLINE | ID: mdl-35877609

ABSTRACT

Using synthetic pesticides to manage pests can threaten pollination services, affecting the productivity of pollination-dependent crops such as avocado. The need to mitigate this negative externality has led to the emergence of the concept of integrated pest and pollinator management (IPPM) to achieve both pest and pollinator management, leading to complementary or synergistic benefits for yield and quality of the harvest. This paper aims to evaluate the potential economic and welfare impact of IPPM in avocado production systems in Kenya and Tanzania. We utilize both primary and secondary data and employed the economic surplus model. On average the potential economic gain from the adoption of IPPM is US$ 66 million annually in Kenya, with a benefit-cost ratio (BCR) of 13:1, while in Tanzania US$ 1.4 million per year, with a BCR of 34:1. The potential benefits from IPPM intervention gains are expected to reduce the number of poor people in Kenya and Tanzania by 10,464 and 1,255 people per year respectively. The findings conclude that policies that enhance the adoption of IPPM can fast-track economic development and therefore improve the livelihoods of various actors across the avocado value chain.


Subject(s)
Persea , Agriculture , Humans , Pest Control , Pollination , Tanzania
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