The melon fly, Bactrocera cucurbitae (Coquillett), represents a devastating agricultural pest species. Conventional chemical control strategies are increasingly compromised by the development of insecticide resistance. Given the pivotal role of the gut microbiota in insect physiology and host fitness, it is necessary to isolate gut-derived bacterial strains from adult melon flies and assess their insecticidal efficacy against adult flies. Isolation of culturable gut microbiota from adult melon flies that died of natural causes yielded 122 bacterial strains. Among the 10 virulent bacterial isolates, Serratia marcescens strain SMLY-1 was identified as a highly pathogenic strain against adult melon flies. In addition, oral administration of SMLY-1 significantly reduced survival rates of adult melon flies in a dose-dependent manner. Histopathological analysis suggested that SMLY-1 administration resulted in progressive midgut damage, which was manifested by epithelial cell desquamation and vacuolization. Moreover, the gut microbiota homeostasis was disrupted, and microbial richness was reduced. Notably, the genus-level Wilcoxon signed-rank test showed a significant increase in Serratia spp. abundance in the SMLY-1 treatment group compared to the control group, indicating abnormal proliferation of Serratia spp. in intestines. Enzymatic assays showed that key digestive enzymes (AMS, LPS, trypsin) and detoxification enzymes (CarE, GST) activities were significantly reduced as well as antioxidant enzymes exhibited significant alterations. qRT-PCR results suggested that immune-related genes in adult melon flies including Attacin, JNK, and PPO were sustained upregulated whereas Cecropin, PGRP, IMD and GST were significantly downregulated. These findings establish SMLY-1 as a promising candidate for the biocontrol of melon flies in the future.

Fruit flies (Tephritidae) significantly threaten mango production and export in Uganda because of direct fruit damage and frequent export rejections, respectively. Accurate species identification is crucial for effective pest management. In Uganda, previous studies relied solely on morphological identification, making it difficult to identify cryptic species. Our study integrated morphological and molecular techniques to assess fruit fly diversity during the May-August 2023 mango season. Surveys were conducted across 20 mango farms in seven districts within Uganda’s two main mango-growing agroecological zones. A total of 256,107 fruit flies were trapped using food baits and para-pheromone lures targeting male Bactrocera, Ceratitis, Dacus , and Zeugodacus species. Morphological screening was performed at the Crop Science Laboratory of Makerere University Agricultural Research Institute, Kabanayolo, PCR confirmation at COVAB’s RTC lab, and Sanger sequencing at Inqaba Biotec. Twenty-one species were documented, ten of which were confirmed to species level: Bactrocera dorsalis, Ceratitis capitata, C. cosyra, C. anonae, Dacus punctatifrons, D. bivittatus, D. eclipsis, D. humeralis, D. armatus , and Zeugodacus cucurbitae . Three species, D. eclipsis, D. humeralis , and D. armatus were reported in Uganda for the first time. The remaining eleven species were identified to the genus level: Ceratitis, Carpomya, Rhagoletis, Dacus , and Zeugodacus. Bactrocera dorsalis was the most abundant (95.5%), dominant, and widely distributed species, followed by D. eclipsis and D. punctatifrons . These findings revealed a high diversity of fruit fly species in Ugandan mango orchards. Further studies and routine molecular surveillance are recommended for comprehensive species monitoring and improved pest management strategies.

Malay apple (Syzygium malaccense L.) is a tropical fruit species grown in the fruit garden section of Liwa Botanical Garden, West Lampung, Indonesia. Insect communities play an important role in agroecosystems because they consist of both pest species and beneficial organisms such as predators and parasitoids. This study aimed to determine insect diversity and dominance on Malay apple plantations in the Fruit Garden of the Regional Technical Implementation Unit (UPTD) of Liwa Botanical Garden. The observation was conducted from September to October 2021 using direct observation, pitfall traps, and yellow sticky traps across five sampling plots arranged diagonally. Insect identification was conducted based on morphological characteristics using relevant literature. Species diversity was evaluated using the Shannon–Wiener diversity index (H’), while dominance was measured using Simpson’s dominance index (C). A total of 1,594 insect individuals belonging to nine orders were recorded, including Diptera, Hymenoptera, Orthoptera, Hemiptera, Coleoptera, Lepidoptera, Dermaptera, Odonata, and Neuroptera. The diversity index (H’) was 1.44, indicating moderate diversity, while the dominance index (C) was 0.43, suggesting low dominance. Diptera was the most abundant order, dominated by fruit flies (Bactrocera dorsalis and Bactrocera cucurbitae). The results indicate that the insect community structure in the Malay apple plantation is relatively balanced, although fruit flies have the potential to become major pests. Increasing plant diversity through flowering plants (refugia) is recommended to support beneficial insect populations and maintain ecosystem stability.

The melon fly, Zeugodacus cucurbitae (Coquillett), is a significant pest of cucurbit crops, and its ovipositing females cause direct damage to fruits. However, existing management strategies primarily target the male population, leaving a critical gap in female-specific control measures. Plant-derived volatiles are environmentally sustainable alternatives for developing behavior-based pest-management tools. The volatiles of the preferred host plant, bitter gourd (Momordica charantia L.), were characterized qualitatively and semiquantitatively using headspace solid-phase microextraction gas chromatography coupled with mass spectrometry (HS-SPME/GC-MS) under targeted sampling conditions. A total of 48 fruit and 44 leaf volatiles were identified, with 28 compounds common to both tissues. Electroantennography (EAG) screenings revealed dose-dependent female antennal responses to 13 compounds, six of which (terpinen-4-ol, trans-verbenol, α-terpineol, 1-decanal, β-caryophyllene and perillaldehyde) exhibited consistent female-specific attraction in behavioral assays. A synthetic six-component blend (each at 10 μg μL-1 in a 1:1:1:1:1:1 ratio) demonstrated a significantly stronger attraction than any individual compound did. Further optimization yielded an optimized four-component formulation comprising terpinen-4-ol, perillaldehyde, trans-verbenol and β-caryophyllene (each at 10 μg μL-1 in a 1:1:1:1 ratio), which effectively attracted both male and female Z. cucurbitae. This plant-based volatile blend offers a targeted candidate attractant with strong potential for subsequent field development for sustainable management of Z. cucurbitae. The six-component blend exhibited potent female-specific attraction, addressing the current control gap for female melon flies, whereas the optimized four-component formulation achieved effective dual-sex attraction and provided a practical tool for integration into monitoring and mass-trapping programs. © 2026 Society of Chemical Industry.

Entomopathogenic fungi are vital components of integrated pest management; however, environmental temperature is one of the key factors that limits their individual-level virulence, population-level transmission dynamics, and field efficacy. In this study, we isolated an indigenous fungal strain from a naturally infected Zeugodacus cucurbitae cadaver, and evaluated its biological characteristics, virulence, and horizontal transmission efficiency against Z. cucurbitae across 20–35 °C. A temperature-driven Susceptible–Infected–Removed (SIR) epidemiological model was developed to simulate infection dynamics and predict its epizootic potential. Morphological and molecular (ITS) analyses identified the isolate as Beauveria bassiana, designated as strain WZS5. WZS5 exhibited notable thermotolerance. At 30 °C, the strain displayed a short median germination time (7.7 h), high sporulation yield (1.1 × 108 conidia mL−1), and fast radial growth (4.8 mm d−1). Additionally, it showed substantial virulence with a median lethal concentration (LC50) of 1.32 × 107 conidia mL−1 and a median lethal time (LT50) of 5.28 days at a concentration of 1.0 × 108 conidia mL−1. Baseline biological activity was maintained even at 35 °C. At 30 °C, horizontal transmission was effective, yielding a cadaver sporulation rate of approximately 70.0%, a 4.0-day sporulation lag, and viable F1 conidia (88.6% germination). The SIR model adequately captured these dynamics (r = 0.919), predicting potential epizootic spread at 30 °C with a basic reproduction number (R0) of 1.90. This predictive framework quantifies temperature thresholds for fungal epizootics, providing valuable ecological insights for managing Z. cucurbitae in tropical and subtropical regions.

The success of insecticide-laced liquid protein bait spray applications relies on attraction and consumption by the target pest. Commercial liquid baits often recommend a broad range of dilution rates, even though many insects adjust their intake of foods based on nutrient concentrations. This compensatory feeding response could influence the amount of toxin ingested, but this impact has not been thoroughly elucidated. We manipulated liquid diet and spinosad concentrations to reveal their effects on consumption and mortality in three lines of melon flies, Zeugodacus cucurbitae, that vary in levels of spinosad resistance. Nutrient concentration had a non-linear effect on consumption, which strongly influenced spinosad-induced mortality. Spinosad-susceptible flies suffered high mortality at the full nutrient concentration range when spinosad concentration was high. Resistant lines consumed less diet overall and hence suffered lower mortality on nutrient concentrations which were excessively dilute (22.5-45 g L-1) and excessively concentrated (720 g L-1). Similarly, the recommended label dilutions of a widely used commercial bait produced low levels of consumption. We demonstrated that a high concentration of toxicant is effective for controlling a susceptible insect population regardless of consumption rate but maximizing consumption may be critical for managing insecticide-resistant populations. © 2026 Society of Chemical Industry.

Endosymbiont-derived microbial volatiles mediate conspecific female attraction in the melon fruit fly Zeugodacus cucurbitae.

The Sterile Insect Technique (SIT) is a crucial method for managing tephritid pest populations by mass-producing, sterilizing, and releasing insects to induce sterile male × wild female matings, leading to population suppression. A major advancement in SIT is the development of genetic sexing strains (GSS), which enable male-only releases. One such strain, based on sex-linked pupal color, has been established for Zeugodacus cucurbitae, a significant agricultural pest. However, the USDA colony, maintained since 2004, has experienced challenges related to inbreeding depression and artificial selection. This study examined the effects of outcrossing Z. cucurbitae females from the T1 genetic sexing strain with wild males on key rearing parameters, including egg production, hatch rate, pupal recovery, weight, emergence rate, response to stimuli, locomotor activity, mating success, time to sexual maturation, and flight ability. Results showed significant improvements in flight ability, weight, and response to stimuli, though a delay in peak egg production was observed in outcrossed females. Interestingly, when competing against wild males for matings with wild females, T1 and outcrossed males showed no significant difference in mating success. These findings provide valuable insights into the potential benefits of integrating wild individuals into long-established laboratory colonies, helping to enhance SIT programs and improve the effectiveness of pest control strategies.

Zeugodacus cucurbitae is a global quarantine pest. Management of this pest relies heavily on chemical insecticides, which impose substantial environmental burdens. Male-specific lures [e.g. cue-lure (CL)] are widely used for monitoring and male-targeted control, but on their own, they often have a limited impact on population suppression. Therefore, efficient attractants targeting both sexes are urgently needed to advance sustainable and integrated pest management (IPM). To address this need, we screened and optimized multicomponent formulations by combining host-plant volatiles, volatiles from the culture supernatant of the gut bacterium Morganella sp. M72, and CL. In behavioral assays, both the optimized host-plant volatile blend (methyl isovalerate: heptanal: methyl myristate: methyl laurate = 10:10:1:0.1) and the volatile blend from the culture supernatant of the gut bacterium Morganella sp. M72 (indole: benzyl alcohol: 3-methyl-1-butanol: 1-undecanol = 0.01:10:10:1) significantly attracted both female and male Z. cucurbitae. When CL was incorporated, the resulting ternary formulation produced significantly higher attraction than any individual blend or single-source formulation. Field trials further supported this improvement, confirming that the ternary blend effectively attracted adults of both sexes under practical conditions. This multicomponent formulation helps overcome the male-only attraction of conventional lures and showed stable field performance across early-season, peak-season and late-season periods. These results support the development of more effective monitoring and integrated management strategies for Z. cucurbitae. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The melon fly, Zeugodacus cucurbitae (Coquillett), is recognized as a globally significant quarantine pest, and it ranks among the most destructive insect species infesting cucurbit and solanaceous crops. However, the molecular mechanisms governing reproductive regulation in female Z. cucurbitae remain poorly characterized, particularly those underlying the reproductive processes mediated by microRNAs (miRNAs). In this study, we firstly identified the ovary-specific gene ZcCTL-S1 in Z. cucurbitae via transcriptomic analysis, and subsequently predicted its targeted miRNAs using bioinformatics approaches. Among these miRNAs, overexpression or inhibition of miR-971-1 and miR-let-7 led to corresponding inverse changes in the transcriptional level of ZcCTL-S1. Notably, only miR-let-7 displayed markedly elevated expression levels in Z. cucurbitae ovaries. Further analyses confirmed that miR-let-7 exhibited a direct targeting relationship with ZcCTL-S1, via a combinatorial approach involving in vivo RNA immunoprecipitation, in vitro dual-luciferase reporter assays, and site-directed mutagenesis techniques. Phenotypic analyses showed that both knockdown of ZcCTL-S1 and overexpression of miR-let-7 significantly inhibited egg hatchability, ultimately compromising the female reproductive capacity of Z. cucurbitae. Collectively, these findings identify a novel miRNA-gene regulatory module in the reproductive development of Z. cucurbitae, and provide novel insights for the development of gene- or miRNA-based pest control strategies.

The study aimed to identify the major insect pests and their natural predators associated with brinjal plants grown under natural farming conditions in the agricultural fields of Tarai region (Uttarakhand). The investigation took place between May and October 2025. The study revealed a total of 13 different insect species belonging to five orders and 12 families, as well as seven natural predators, related to the brinjal crops at various growth stages. The key insect pests found on brinjal included whiteflies (Bemisia tabaci), mealybugs (Coccidohystrix insolita), aphids (Myzus persicae), leaf rollers (Eublemma olivacea), lace bugs (Urentius sentis), brinjal shoot and fruit borers (Leucinodes orbonalis), grasshoppers (Melanoplus differentialis), jassids (Amrasca biguttula biguttula), hadda beetles (Henosepilachna vigintioctopunctata), red cotton bugs (Dysdercus cingulatus), bagrada bugs (Bagrada hilaris), green stink bugs (Nezara viridula) and melon fruitflies (Bactrocera cucurbitae). Among the natural predators recorded were ladybird beetles (Coccinella spp.), burmese lynx spiders (Oxyopes birmanicus), striped lynx spiders (Oxyopes salticus), black garden ants (Lasius niger), ghost ants (Tapinoma melanocephalum), ground beetles (Ophionea nigrofasciata), dragonflies (Crocothemis servilia), hoverflies (Ischiodon scutellaris), and parasitic wasps (Netelia ephippiata).

In vitro evaluation of soil-borne fungal isolates for their virulence against melon fly (Bactrocera cucurbitae) adults in Swat, Pakistan

A simple template loop-mediated isothermal amplification (LAMP) assay for rapid on-site detection of melon fly, Zeugodacus cucurbitae

Understanding the ovipositional preferences of insect pests is essential for developing effective management strategies in agricultural systems. Zeugodacus cucurbitae (Coquillett) is a highly destructive tephritid fruit fly that infests fruits at various maturity stages, causing significant damage to economically important crops such as Melon Manis Terengganu (MMT). This study investigated the ovipositional preference of Z. cucurbitae across three fruit maturity stages—unripe, ripe, and fully ripe—under no-choice and choice experimental conditions. In the no-choice experiment, pupal formation (7.44 ± 2.10 pupae) and adult emergence (6.20 ± 2.03 flies) were significantly lower (P < 0.05) in unripe MMT, whereas the percentage of adult emergence and sex ratio did not differ significantly (P > 0.05) among fruit maturity stages. Under choice conditions, pupal formation was also significantly lower (P < 0.05) in unripe MMT (11.40 ± 4.68 pupae), while fully ripe fruits supported significantly higher (P < 0.05) male (51.70 ± 21.07%) and female (55.00 ± 26.59%) emergence. Correlation analysis revealed significant relationships (P < 0.05) between pupal formation, adult emergence, and fruit characteristics in the choice experiment. These findings demonstrate a strong preference of Z. cucurbitae for fully ripe MMT as oviposition sites, indicating that fruit maturity plays a critical role in host selection. This study provides valuable insights for the development of targeted pest management strategies, including early-stage fruit protection, to reduce infestation in MMT cultivation.

Chemical control has traditionally served as the principal method for managing pests in cucurbit crops; however, the urgent need to mitigate environmental risks and ensure food safety has driven the exploration of sustainable alternatives. The present study was carried out during Kharif 2024 at the Entomology Laboratory, ICAR–Indian Institute of Vegetable Research, Varanasi, to evaluate the influence of insecticides from diverse chemical groups on the biology and morphometrics of the melon fruit fly, Zeugodacus cucurbitae. The test insecticides included chlorantraniliprole, cyantraniliprole, thiamethoxam, imidacloprid, indoxacarb and azadirachtin. Their effects were examined on developmental duration, adult longevity, oviposition period, fecundity and body dimensions. The results revealed that anthranilic diamides exerted the most pronounced impact. Chlorantraniliprole and cyantraniliprole markedly prolonged developmental time (female longevity of 37.23 and 33.76 days, respectively, versus 30.82 days in control) and azadirachtin, as well as cyantraniliprole, significantly suppressed fecundity (52.40 and 54.26 eggs compared with 81.40 in control). Among concentrations, imidacloprid at 16 ppm (45.33 eggs) and azadirachtin at 16 ppm (50.48 eggs) per female adult caused the greatest reduction in fecundity, whereas indoxacarb at 4 ppm showed minimal effect (79.78 eggs). Morphometric traits were similarly affected, with chlorantraniliprole reducing larval length (1st instar 1.49 mm and 3rd instar 9.15 mm against 1.85 mm and 10.05 mm in control) and adult female width (13.55-14.41 mm vs 15.79 mm in control). Indoxacarb responses closely resembled control, while azadirachtin produced intermediate suppression. Overall, the findings indicate that anthranilic diamides, particularly chlorantraniliprole and cyantraniliprole, along with the botanically derived azadirachtin, are promising candidates for disrupting the growth and reproduction of Z. cucurbitae. When used in rotation or integrated with botanicals and ecological strategies, these insecticides can form a sustainable foundation for melon fruit fly management.

Species in the genus Enterobacter are widely distributed and occupy diverse ecological niches. Although many species within this genus have been extensively isolated and characterized, their symbiotic associations with Tephritidae fruit flies remain understudied, particularly through comparative genomic analyses. To address this gap, we conducted a whole-genome comparative analysis of thirteen Enterobacter strains isolated from the most economically significant fruit fly species: Anastrepha fraterculus, Bactrocera dorsalis, Bactrocera zonata, Ceratitis capitata, and Zeugodacus cucurbitae. The results revealed that different fruit flies harbor distinct Enterobacter species, with Enterobacter hormaechei being the most prevalent across hosts. Notably, distinct E. hormaechei subspecies were associated with specific hosts, suggesting a potential host-driven adaptation and coevolution. Pangenome analysis highlighted a dynamic genetic structure among these strains, with significant differences in the core, shell, and species-specific gene composition. The high proportion of metabolism-related genes in the core genome suggests a conserved role in essential biological functions, whereas the enrichment of mobile genetic elements (prophages and transposons) and cell motility genes within the shell and species-specific genomes highlights the genomic plasticity and potential host-specific adaptations. Three distinct subtypes of T6SS (type VI secretion systems) gene clusters, T6SS_C1, T6SS_C2, and T6SS_C3, were detected across Enterobacter strains. T6SS_C1 and T6SS_C2 were identified in most Enterobacter strains, whereas T6SS_C3 cluster was restricted to a single isolate. Although these clusters contained thirteen core T6SS genes, they were characterized by different gene synteny and effector/immunity gene content, suggesting that different Enterobacter strains may utilize distinct mechanisms for interbacterial interactions, host manipulation, and environmental adaptation. Overall, our findings reveal the genetic basis of the symbiosis between Enterobacter species and fruit flies, shedding light on their evolutionary dynamics, diversity of T6SS, and functional traits. These results open new avenues for developing microbiome-based strategies for pest management, including the targeted manipulation of microbial communities to enhance sterile insect technique (SIT) outcomes.

Zeugodacus cucurbitae (Diptera: Tephritidae) is a major pest of cucurbit crops, and its laboratory rearing typically relies on expensive methods requiring artificial diets and specialized infrastructure. In resource-limited settings, these requirements represent a substantial barrier to establishing stable colonies, which are nevertheless essential for bioecological studies and integrated pest management programs. This study describes a simple, low-cost, and reproducible rearing technique adapted to local conditions in Senegal. Naturally infested watermelon fruits were collected and incubated at ambient temperature (26-32 °C), relative humidity of 47-72%, and a 12L: 12D photoperiod. Larvae developed within the fruit pulp and subsequently pupated in a sterilized sand substrate. Pupae were collected daily, incubated in ventilated containers, and monitored until adult emergence. Adults were maintained in simple cages and provided with a diet consisting of watermelon juice, sugar, water, and yeast. Oviposition was induced by offering pieces of fresh watermelon, enabling the production of a new generation without the need for artificial diets. This method provides a reliable and easily implementable alternative for maintaining Z. cucurbitae colonies in the laboratory, thereby supporting entomological research and the assessment of sustainable management strategies.

• The melon fly is a significant pest of cucurbit crops. • Metarhizium anisopliae is a virulent entomopathogen against the pest. • Courgette yield is increased when M . anisopliae is applied in autodissemination devices or through soil drench. • Courgette yield is highest in combined applications. The melon fly Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae) is a significant pest of cucurbit crops, responsible for substantial yield losses and economic damage across Asia and Sub-Saharan Africa. Control of this pest currently relies heavily on synthetic insecticides, which are associated with environmental and human health risks, and contribute to the development of insecticide resistance. Entomopathogenic fungi offer a promising eco-friendly alternative, yet effectiveness of delivery methods remains a critical limitation in their widespread adoption. This study evaluated the efficacy of three application modes of Metarhizium anisopliae (Mechnikov) Sorokin (Hypocreales: Clavicipitaceae) isolate ICIPE 69, autodissemination devices (AD), soil inoculation (soil), and their combination (AD + soil), for control of Z. cucurbitae in courgette Cucurbita pepo L. (Cucurbitales: Cucurbitaceae) cultivated in field cages. Experiments were conducted in triplicate for two seasons i.e., April to August 2021 (season one) and October 2021 to February 2022 (season two). Infestation with 400 Z. cucurbitae (1: 1 male: female) adults and application of treatments was conducted at the onset of flowering. Fungal conidia acquisition of flies, conidial persistence in soil, Z . cucurbitae population dynamics and C . pepo yield were assessed. Flies in the AD treatment acquired the highest number of conidia (13.17 ± 0.89 conidia/fly) while those in the soil treatment acquired the lowest (0.87 ± 0.27 conidia/fly). AD + soil treatment significantly reduced Z . cucurbitae puparial recovery and suppressed adult fly populations more effectively than the individual treatments. The highest marketable yield was recorded in the AD + soil treated field cages while lowest yield was recorded in the control. These findings underscore the potential of combining entomopathogenic fungus delivery strategies to improve biological control of Z. cucurbitae and enhance crop productivity. Further field evaluations for compatibility with other biological control interventions and economic analyses are recommended to facilitate uptake among farmers.

Fruit flies of the genus Bactrocera (Diptera: Tephritidae) are among the most destructive insect pests of fruits and vegetables in tropical and subtropical regions, causing significant economic losses in Bangladesh. Accurate identification of these species remains challenging because of their morphological similarity and the presence of cryptic taxa, while molecular data from Bangladesh are still limited. To fill this gap, extensive field surveys and laboratory analyses were conducted to determine the species composition, host associations, and infestation patterns of fruit flies across major agroecological regions of Bangladesh. Adult flies were collected using pheromone traps and reared from infested fruits and vegetables. Morphological identification followed standard taxonomic keys, and molecular confirmation was performed through cytochrome oxidase subunit I (COI) gene sequencing. Morphological observations revealed Bactrocera cucurbitae (melon f ly) and B. dorsalis (oriental fruit fly) as the predominant species in all surveyed sites. COI sequencing of 27 specimens resolved four major clades: B. dorsalis, B. tau (pumpkin fruit fly), B. cucurbitae, and B. scutellate (striped fruit fly), with B. scutellata representing the first confirmed record in Bangladesh. A sample initially identified morphologically as Ceratitis capitata was molecularly confirmed as B. tau, highlighting the limitations of morphology-based identification. These results reaffirm the dominance of B. dorsalis and B. cucurbitae in Bangladeshi fruit and vegetable ecosystems and highlight the value of integrating molecular diagnostics with traditional taxonomy. The findings provide crucial baseline information for species-specific, sustainable fruit fly management and strengthen the molecular framework for future tephritid research in Bangladesh.

Assessment of resistance traits in bitter gourd genotypes against melon fruit fly (Bactrocera cucurbitae Coquillett): morphological and biochemical insights