Search Results (83)

Parasitoid wasps are vital for biological control, and while new species continue to be discovered, evaluating their biological characteristics is crucial for realizing their potential for pest management. Pachycrepoideus vindemiae (Rondani) (Hymenoptera: Pteromalidae) is a well-studied parasitoid of dipteran pests, while Trichomalopsis ovigastra Sureshan & Narendran (Hymenoptera: Pteromalidae) has been only morphologically described. To assess its biocontrol potential, we compared the biological traits of T. ovigastra and P. vindemiae using Drosophila melanogaster Meigen (Diptera: Drosophilidae) and Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) as hosts. T. ovigastra showed significantly higher parasitism rates, especially against B. dorsalis, where T. ovigastra achieved nearly 50% parasitism, compared to less than 0.3% by P. vindemiae. When using D. melanogaster as the host, no significant differences were observed between T. ovigastra and P. vindemiae in offspring sex ratio or adult longevity; however, T. ovigastra exhibited a shorter developmental duration and greater tolerance to temperature extremes, starvation, and desiccation. Notably, B. dorsalis has expanded its range from southern to northern China; however, no native parasitoids of this pest have been reported in the newly invaded northern regions. T. ovigastra, collected from northern orchards and capable of parasitizing B. dorsalis, thus shows promise as a biocontrol agent. These findings highlight the potential of locally occurring parasitoids, although field validation is still required. Full article

The role of abiotic factors in the allelopathic interactions between copepods and rotifers is poorly documented. Temperature has a marked effect on the metabolism of zooplankton. Therefore, the release of allelochemicals by copepods and the response of rotifers to them may change as temperatures increase. Here, we tested the effect of two temperatures (20 and 25 °C) on the population growth of Brachionus havanaensis cultured on a conditioned medium (CM) of Arctodiaptomus dorsalis and Eucyclops sp. The CM was obtained daily, separately, for the males and females of both copepod species at a density of 0.1 ind. mL⁻¹ for 24 h prior to experiments. In the controls and CM treatments, higher temperatures had a stimulatory effect on the population growth and the rate of population increase (r) of B. havanaensis. At 25 °C, the CM from the females and males of A. dorsalis caused >30% increase in r, but for the CM from Eucyclops sp., this effect was lower (<21%). At 20 °C, the r in the controls and CM treatments was not significantly different. The morphometry of B. havanaensis varied depending on the treatments. Compared to controls, longer loricae were recorded in the CM of male A. dorsalis at both temperatures. However, in the CM of female calanoids, longer rotifers were observed only at higher temperatures. At 20 °C, the CM from Eucyclops produced smaller loricae. The relationship between the lorica length and width of rotifers showed a linear relation but the slope differed among the treatments. Full article

The oriental fruit fly (B. dorsalis) poses a critical threat to domestic mandarin trade, necessitating effective phytosanitary measures. This study evaluated ethyl formate (EF) and phosphine (PH₃) fumigation as alternative disinfestation methods, either alone or in combination with cold treatment, using B. scutellata, pumpkin fruit fly, as a surrogate species. Eggs and third-instar larvae were tested under both naked and inoculated conditions. Results indicated that larvae were more susceptible to treatment than eggs. The LT_99% values for cold treatment (1.7 °C) were 8.6 and 12.4 days under naked and inoculated conditions, respectively. EF LCt_99% values were 265.7 and 1111.0 g h/m³. EF (LCt_50%) combined with PH₃ (1.0 g/m³) achieved up to 100% mortality, while EF (LCt_50%) followed by cold treatment (1.7 °C for 1–3 days) significantly enhanced mortality compared to cold treatment alone. This study offers foundational data to optimize EF-based quarantine treatments against B. dorsalis, supporting shorter treatment times and more cost-effective quarantine practices. Future studies should validate these findings under practical field conditions. Full article

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), a highly destructive pest, affects fruits and vegetables globally, leading to significant economic losses. As a homomeric subunit of γ-aminobutyric acid (GABA) receptors, RDL plays a crucial role in various physiological activities in insects. However, functional characterization of RDL from B. dorsalis has not yet been elucidated. Here, we cloned the Rdl gene from B. dorsalis, BdRdl, and investigated the expression pattern of BdRdl. The results showed that BdRdl was highly expressed in pupae and the heads of male and female adults. Also, we characterized the BdRDL in Xenopus oocytes through two-electrode voltage clamping. It turned out that the inward current of BdRDL induced by GABA was followed in a dose-dependent manner with a median effective concentration (EC₅₀) of 2.4 × 10⁻⁴ M. Additionally, we determined the mode action of fluralaner, a new insecticide, on BdRDL in oocytes. We found that fluralaner significantly inhibited the currents induced by GABA, suggesting that fluralaner worked as an antagonist of BdRDL. Furthermore, we found that fluralaner exhibited a comparable insecticidal activity to avermectin against B. dorsalis adults. Lastly, the modeling and molecular docking predicted that fluralaner interacted with RDL via hydrogen bonds. Our results not only characterized the RDL of B. dorsalis, but also revealed that fluralaner works as an antagonist of BdRDL and could be used as an effective strategy for B. dorsalis control. Full article

The Zeugodacus cucurbitae and Bactrocera dorsalis are economically significant pests that share similar habitats and host plants, leading to intense interspecific competition. To elucidate their competitive interactions, this study investigated the oviposition competition behavior of mixed laboratory populations on five common host plants: pumpkin (Cucurbita moschata), cucumber (Cucumis sativus), winter melon (Benincasa hispida), bitter melon (Momordica charantia) and guava (Psidium guajava). The results exhibited that among the five hosts tested, B. dorsalis exhibited a significant competitive advantage in oviposition on pumpkin and bitter melon, with its fecundity greater than that of Z. cucurbitae across all ratios. Conversely, Z. cucurbitae showed a clear preference for cucumber. Except at the extreme ratio of 16:4, where B. dorsalis laid slightly more eggs than that of Z. cucurbitae, Z. cucurbitae laid more eggs at all ratios. The results can provide a reference for further investigation on the oviposition selectivity and interspecific competition between the adults of Z. cucurbitae and B. dorsalis. Full article

Bactrocera dorsalis (Hendel) is an invasive fruit and vegetable pest, infesting citrus, mango, carambola, etc. We observed that the posterior thoracic scutella of some B. dorsalis adults are yellow, some light yellow, and some white in China. Compared with the B. dorsalis races with a yellow scutellum (YS) and white scutellum (WS), the race with a light-yellow scutellum (LYS) is dominant in citrus and carambola orchards. To reveal genetic correlates among the three races, the genomes of 22 samples (8 with YS, 7 with LYS, and 7 with WS) were sequenced by high-throughput sequencing technology. Single-nucleotide polymorphism (SNP) annotation showed that there were 17,580 non-synonymous mutation sites located in the exonic region. Principal component analysis based on independent SNP data revealed that the SNPs with LYS were more similar to that with YS when compared with WS. Most genes associated with scutellum color variation were involved in three pathways: oxidative phosphorylation, porphyrin and chlorophyll metabolism, and terpenoid backbone biosynthesis. By comparing the sequences among the three races, we screened out 276 differential genes (DGs) in YS vs. WS, 185 DGs in LYS vs. WS, and 104 DGs in YS vs. LYS. Most genes determining color variation in B. dorsalis scutella were located on chromosomes 2–5. Biochemical analysis showed that β-carotene content in YS and LYS was significantly higher than that in WS at any stage of adult days 1, 10, and 20. No significant differences were observed in cytochrome P450 or melanin content in YS, LYS, or WS. Our study provides results on aspects of scutellum color variation in B. dorsalis adults, providing molecular and physiological information for revealing the adaptation and evolution of the B. dorsalis population. Full article

Food-baited traps are an important part of early detection programs for invasive tephritid fruit fly species, as they are attractive to both sexes of all targeted species. Torula yeast borax (TYB) mixture is a standard food bait, but its longevity is limited (1–2 weeks). Synthetic food-based lures have been developed, including ammonium acetate, putrescine, and trimethylamine. However, the different formulations of these synthetic lures vary greatly in their attractiveness and longevity. Here, we present the results of field trapping in several Central and South American countries as well as Hawaii that compared captures of Ceratitis capitata, Anastrepha spp., and Bactrocera dorsalis in traps baited with torula yeast borax, which was replaced weekly, versus traps baited with newly developed vial-lures, which contained the same three components noted above and were not replaced over 6–10 weeks of trapping. In all countries, captures of C. capitata in vial-lure-baited traps were equal to or greater than captures in TYB-baited traps. However, the vial-lures attracted fewer B. dorsalis than TYB, and data were inconsistent for Anastrepha spp. The implications of these results for large-scale detection programs are discussed. Full article

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is a notable agricultural pest that undergoes pupation in the soil. Mortality risk from predation and parasitism decreases as the depth of the pupal location increases from the ground surface, with a one-centimetre increase in depth causing a significant change. Soil properties, such as moisture and hardness, influence pupation depth, but the effect of temperature has not been fully tested. This laboratory study examined whether a biologically important variation in pupation depth (e.g., one centimetre) is caused by naturally experienced temperature variations (20 to 35 °C) in B. dorsalis. The temperature–pupation depth relationship revealed a unimodal pattern, with the deepest pupation occurring at intermediate temperature levels and shallower pupation at the two extreme temperature ranges. Strong quantitative effects were observed, with the highest mean pupation depth of 40.8 mm at 27.5 °C and the lowest mean pupation depth of 15 mm at 35 °C. The observed quantitative effect suggests that temperature can strongly affect pupal mortality from predators and parasitoids by influencing pupation depth. Future studies that reveal the ability of biological control agents to forage underground for pupae at different temperatures are awaited, as this is key information for evaluating the effectiveness of these agents. Full article

Fusarium solani KMZW-1 is recognized for its potential as a biocontrol agent against agricultural and forestry pests, particularly due to its compatibility with integrated pest management (IPM) strategies. This study aimed to investigate the complete genome of F. solani KMZW-1 and assess its pathogenicity against Bactrocera dorsalis. Whole-genome sequencing revealed a genome size of 47,239,278 bp, comprising 27 contigs, with a GC content of 51.16% and fungus identified as F. solani KMZW-1. The genome completeness was assessed as 97.93% using BUSCO analysis, the DFVF sequence identifier was Fusarium 0G092560.1, and AntiSMASH analysis identified 35 gene clusters associated with secondary metabolite biosynthesis, providing insights into the genetic basis of its pathogenic mechanisms and biocontrol potential. Comparative genomic analysis found 269 unique genes for F. solani KMZW-1, and collinearity analysis exhibited a high degree of synteny with Fusarium solani-melongenae. The pathogenicity of F. solani KMZW-1 was assessed using concentrations ranging from 1 × 10⁴ to 1 × 10¹¹ conidia/mL. Higher concentrations (1 × 10¹⁰ to 1 × 10¹¹ conidia/mL) resulted in significantly increased cumulative mortality rates of B. dorsalis adults compared to the control group. Notably, the pathogenicity was higher in male adults than in females. Probit analysis yielded LC₅₀ (50% lethal concentration) values of 5.662 for female and 4.486 for male B. dorsalis adults. In summary, F. solani, KMZW-1 exhibits strong insecticidal activity against B. dorsalis and shows potential as a biocontrol agent with IPM strategies. These findings provide robust genomic evidence supporting the use of F. solani KMZW-1 in managing against B. dorsalis populations. Full article

Bactrocera dorsalis is a highly invasive and destructive pest distributed worldwide. Chemical insecticides remain the primary measure for their control; however, this species has already developed resistance to several insecticides. In recent years, there have been several reports of monitoring B. dorsalis resistance in China, but continuous monitoring results are lacking and do not even span a decade. In this study, we monitored the dynamics of resistance to seven insecticides among 11 geographically distinct Chinese populations of B. dorsalis (2010–2013; follow-up in 2023). The 11 populations were found to adapt rapidly to antibiotic insecticides (spinosad, emamectin benzoate, and avermectin), reaching high levels of insecticide resistance in several areas. Overall, a decreasing trend in resistance to organophosphorus insecticides (chlorpyrifos and trichlorfon) was observed, whereas pyrethroid (beta-cypermethrin and cyhalothrin) resistance trends were observed to both increase and decrease. The monitoring of field resistance among different B. dorsalis populations over the duration of this study is important for improving the efficiency and sustainability of agricultural pest management, and the results provide a scientific basis for the development of more effective resistance management strategies. Full article

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is a global economic pest that poses a serious threat to the fruit industry. In the southwest of China, Yunnan Province sustains a severe infestation of B. dorsalis. An automated monitoring system designed for B. dorsalis was employed in this study to elucidate the annual population dynamics of B. dorsalis in four counties: Yuanjiang, Huaping, Guangnan, and Ludian in Yunnan. The system utilizes sex parapheromone and image recognition technology. The data uploaded by the device are used to analyze the annual population dynamics of B. dorsalis in different regions. The results showed that the populations of adult B. dorsalis in all four counties peaked twice annually, with Yuanjiang experiencing the earliest peak periods, followed by Huaping, Guangnan, and Ludian. Adult B. dorsalis occurred in Yuanjiang throughout the year, and Yuanjiang had the highest number of B. dorsalis monitored. In Huaping, adult B. dorsalis occurred in March–December and was highly active, with a high population density in 2019. Bactrocera dorsalis did not occur in December in Guangnan but only in May–October in Ludian. Bactrocera dorsalis abundance was correlated with temperature in all four areas. The outcomes of this experiment provide a practical foundation for developing control strategies targeting B. dorsalis in various orchards across each county. Full article

Fruit flies cause substantial economic damage, and their management relies primarily on chemical insecticides. However, pesticide resistance has been reported in several fruit fly species, the mitigation of which is crucial to enhancing fruit fly control. Here, we assess the toxicity of a novel insecticide (fluralaner) and a common insecticide (dinotefuran) against three fruit fly species, Bactrocera dorsalis (Hendel), Bactrocera cucurbitae (Coquillett), and Bactrocera tau (Walker). Both pesticides exhibit robust lethal and sublethal effects against all three fruit fly species, with fluralaner being more potent. Fluralaner and dinotefuran suppress the reproductive capacities and survival rates of fruit flies. However, at the 50% lethal concentration, fluralaner stimulates the reproductive capacity of B. dorsalis and the survival rate of B. tau. Fluralaner also causes significant transgenerational effects, impacting the offspring hatching rate of B. cucurbitae and B. tau and reducing the proportion of female offspring. Thus, both pesticides exhibit high potential for controlling fruit flies. However, their application should be tailored according to species variations and the diverse effects they may induce. Collectively, the findings of this study outline the sublethal effects of two insecticides against fruit flies, helping to optimize their application to ensure the effective management of insecticide resistance. Full article

Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is one of the most devastating agricultural pests worldwide due to its high reproductive and invasive abilities. The elucidation of its gonadal developmental characteristics and the identification of sex-related genes will provide a useful genetic basis for reproductive-based pest control. Here, the gonadal transcriptome of B. dorsalis was sequenced, and novel gonad-specific expressed genes were analyzed. A total of 1338, 336, 35, and 479 differentially expressed genes (DEGs) were found in the testis (TE), ovary (OV), female accessory gland (FAG), and male accessory gland (MAG), respectively. Furthermore, 463 highly expressed gonad-specific genes were identified, with the TE having the highest number of specific highly expressed genes, at 402, followed by 51 in the OV, 9 in the MAG, and only 1 in the FAG. Strikingly, approximately half of highly expressed gonad-specific genes were uncharacterized. Then, it was found that 35, 17, 3, 2, and 1 of 202 uncharacterized highly expressed TE-specific genes encoded proteins that contained transmembrane domains, signal peptides, high-mobility group boxes, the zinc finger domain, and the BTB/POZ domain, respectively. Interestingly, approximately 40% of uncharacterized highly expressed gonad-specific genes encoding proteins were not predicted to possess functional motifs or domains. Finally, the spatiotemporal expression and sequence characterization of six novel highly expressed gonad-specific genes were analyzed. Altogether, our findings provide a valuable dataset for future functional analyses of sex-related genes and potential target sites for pest control. Full article

The oriental fruit fly, Bactrocera dorsalis (Hendel), poses a significant threat to the global fruit industry, causing damage to diverse fruits like citrus, mango, and guava. Chemical pesticides have limited effectiveness, and pesticide residues and pesticide resistance are pressing issues. Therefore, it is essential to develop environmentally friendly pest control methods to address this problem. Behavior-modifying chemicals, including male attractants and intersex protein baits, play a critical role in the control of B. dorsalis. The mature host fruit serves as both an oviposition site and food source under natural conditions, making it a potential attraction source for oriental fruit flies. Orange, Citrus sinensis, is a main host of B. dorsalis, and commercial orange juice is a common attractant for the egg laying of B. dorsalis. Although it can both attract and elicit oviposition behaviors in B. dorsalis adults, its active components are still unclear. This study utilized analytical chemistry, behavioral tests, and electrophysiology to identify the active components of commercial orange juice that attract B. dorsalis, with the aim of providing a reference for the development of behavior-modifying chemical-based techniques to control B. dorsalis. Five compounds with a high abundance were identified via a GC-MS, including D-Limonene, butanoic acid ethyl ester, β-myrcene, linalool, and α-terpineol. Behavioral and electrophysiological experiments uncovered that D-Limonene was the active substance that was the main attractant in the mixture of these five substances, evoking a strong electrophysiological response in adult B. dorsalis. D-Limonene strongly attracts adult B. dorsalis only when they are sexually mature, and the attraction is not rhythmic. Olfaction plays a leading role in the attraction of D-Limonene to adult B. dorsalis, and Orco^−/− mediates the perception of D-Limonene by B. dorsalis. Overall, D-Limonene is one of the key attractant compounds for B. dorsalis in the volatile compounds of commercial orange juice, offering possible support for the development of behavior-modifying chemical-based technology to control B. dorsalis in the future. Full article

Predators are dependent on the capture of prey to meet their energetic and nutritive requirements, which brings the risk of predation to prey. The predation risk is divided into consumptive and non-consumptive effects. Non-consumptive effects may manifest through altered growth and ontogenetic trajectories in prey species, a dynamic modulated by olfactory or other sensory cues from predators. Bactrocera dorsalis Hendel represents a major invasive threat to global horticulture. While earlier research was primarily centered on the consumptive interactions between B. dorsalis and its natural enemies, the potential consequences of non-consumptive interactions on the development of B. dorsalis have been overlooked. In this study, we investigated the impact of predation risk effects, induced by both visual exposure to the predatory mantis Hierodula patellifera Serville and its associated odor, on the life history traits of B. dorsalis. Female B. dorsalis demonstrated a reduced developmental time in the presence of a caged predator (H. patellifera) or predator odors, but showed significantly increased fecundity. Conversely, males displayed no significant change in developmental time. Additionally, neither the female nor male body weight at death was significantly influenced by the predation risk from the caged predator or predator odors. This study investigated the effects of predation risk on the development and reproduction of B. dorsalis, emphasizing the potential importance of odor risk in biological and pest control. Full article