Bulletin of Entomological Research最新文献

The Hyphantria cunea (Drury) is a highly polyphagous invasive pest that has become widespread and destructive in China. Although sex pheromone components of H. cunea have been identified, the weak field attraction of synthetic sex pheromone has hindered the application of sex pheromone-based lures in efficient monitoring and management of this pest. In this study, the electroantennographic (EAG) and field responses of H. cunea male adults to three synthetic sex pheromone components, including Z9, Z12, Z15-18Ald (C18:Ald), Z3, Z6-9S,10 R-epoxy-21Hy (C21-2Epo), and 1, Z3, Z6-9S,10 R-epoxy-21Hy (C21-3Epo), were evaluated. Male antennae exhibited significant dose-dependent response to three individual components and a ternary mixtures. The younger and virgin male moths showed stronger electrophysiological activity to synthetic compounds, whereas sensitivity decreased significantly after mating. Among the three components, C21-3Epo elicited the strongest antennal responses. Field trapping revealed that neither single compounds nor binary blends attracted males, whereas only the ternary blend of C18:3Ald, C21-2Epo, and C21-3Epo (ratio 8:1:1; 10 mg total load) effectively captured large numbers of males. In addition, the field trapping indicated that the green rubber septum functioned as a practical dispenser for synthetic pheromones. The Unitraps baited with the green rubber septum showed significantly higher trapping efficiency than cotton wicks, highlighting the septum as a promising dispenser for field deployment of synthetic sex pheromones. Finally, the green rubber septum baited with a ternary blend monitored the dynamics of H. cunea occurrence and detected that the emergence period overlapped with the commercially available synthetic lure. In general, the bioactivity of the synthetic sex pheromone of H. cunea was validated. It could effectively capture H. cunea male adults, be used to monitor and control H. cunea, and further be incorporated into the integrated pest management programme.

In tritrophic interactions, host plants could influence not only the population of insect pests but also that of their natural enemies. This study examined the effect of three wheat cultivars on demographic parameters of Schizaphis graminum Rondani (Hemiptera: Aphididae) and its predator, Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae). Furthermore, the secondary metabolites, photosynthetic pigments, and defence enzymes of wheat cultivars were evaluated at different times. According to the results, the highest and lowest developmental times of S. graminum were found on cultivar (cv.) Morvarid and cv. Ehsan, respectively. However, it was vice versa for the predator, being highest on cv. Ehsan and lowest on cv. Morvarid. Adults of S. graminum lived shorter on cv. Morvarid, while males and females of H. variegata lived longer on this cultivar. The intrinsic rate of natural increase (r) of S. graminum ranged from 0.347 to 0.456 day^-1, and that of H. variegata from 0.118 to 0.176 day^-1 on different cultivars. The value of this parameter was lowest for aphids but highest for their predator on cv. Morvarid. Based on the results, cv. Morvarid at 120 hours post-infestation by S. graminum contained the greatest concentrations of secondary metabolites and enzyme activities. The time-dependent loss of photosynthetic pigments occurred in each tested cultivar. The results revealed that cv. Morvarid had a suitable potential for reducing the population of S. graminum and enhancing the performance of H. variegata. However, further studies are needed to evaluate the complementary interactions of cv. Morvarid and H. variegata in controlling S. graminum population under natural conditions.

Predatory mites are important biological control agents of spider mites in various crops. Long-term mass rearing on alternative foods, such as plant pollen, may affect their predatory efficiency, but data on Euseius scutalis are scarce. Therefore, this study aimed to evaluate whether long-term rearing of E. scutalis on cattail pollen influences its functional response when fed on Tetranychus turkestani. Functional and numerical responses of the predatory mite E. scutalis reared on cattail (Typha latifolia) pollen over 30 generations on different densities (2, 4, 8, 16, 32, 64, and 128) of T. turkestani were evaluated. The results indicated a type II functional response for E. scutalis on T. turkestani in all generations (G1, G10, G20, and G30) tested. The attack rate (a) of E. scutalis increased as the number of generations increased. The handling time decreased as the number of generations increased from G1 (0.330 h) to G10 (0.318 h), then increased in G20 (0.572 h) and then decreased again in G30 (0.385 h). In G1 and G30, the number of eggs deposited by the predator increased as prey density increased. However, in G10 and G20, egg deposition increased up to 64 prey and then slightly decreased at 128 prey. The results indicated that the quality of E. scutalis did not lessen against T. turkestani after different periods of rearing on cattail pollen. Based on this study, we recommend cattail pollen as a good candidate for the large-scale rearing of E. scutalis for use in biological control programmes against T. turkestani.

Parasitoids play a key role in biological control, regulating pest populations in natural and agricultural ecosystems. Their efficiency depends on a thorough understanding of host-parasitoid interactions. Among these, the functional response, the relationship between parasitism rate and host density, plays a critical role. Despite a well-established background, challenges remain in experimental design, model selection, and parameter estimation for functional response analysis in parasitoids. This study aims to provide a practical guide to addressing these challenges. We outline key considerations in experimental design, including the selection of model organisms and initial host densities. For model selection, we present methods to differentiate between Type II and Type III functional responses, identifying the best-fitting models for parasitoids. In parameter estimation, we present an example demonstrating the application of functional response models for each type, including parameter estimation to guide model choice. Additionally, we provide equations and code based on published data to facilitate parameter comparisons. This guide provides a structured framework for experimental design, parameter estimation, and model selection in functional response studies, which is adaptable to various host-parasitoid interactions. By enhancing methodological rigour, we aim to support researchers in improving the precision and applicability of functional response analyses in parasitoid research.

Soybean aphids (Aphis glycines) (Hemiptera: Aphididae) pose a serious threat to global soybean production, necessitating sustainable control strategies. This study investigated silica nanoparticles (SiNPs) as an eco-friendly alternative, hypothesising they would suppress aphid populations while enhancing plant growth. Soybean plants were foliar-sprayed with SiNPs (0-1 mmol/L), and aphids were assessed across six assays: fecundity, survival, feeding preference, weight gain, olfactory response, and plant morphometrics. SiNPs significantly reduced aphid nymphal production and population growth at all concentrations but did not affect survival, weight gain, or host-seeking behaviour. Plant responses were mixed: leaf width increased at higher SiNPs doses, but plant height decreased, with no effects on leaf length, root/shoot biomass, or root length. These findings suggest that SiNPs could disrupt aphid reproduction without triggering behavioural avoidance. The absence of biomass reduction indicates potential for crop compatibility. This laboratory study reveals a novel, reproduction-targeted mode of action for SiNPs, highlighting its potential as a candidate for future development in sustainable IPM strategies. Further field-scale validation is required to confirm these effects under real-world conditions.

Lygus hesperus is an economically important pest of many crops. An effective monitoring method for the early detection of L. hesperus could improve its management. A recently developed pheromone lure has been shown to attract L. hesperus males, however, fewer males were captured than expected. It is unknown whether this was an effect of pheromone responsiveness or the type of trap used. Thus, we compared the efficacy of the previously used white delta sticky traps to red cylindrical sticky traps in strawberry fields in California and cotton fields in Arizona. Collections were made 1 and 2 weeks after trap deployment. In strawberry, pheromone baited traps captured more L. hesperus males than unbaited traps. More males were collected from baited red cylindrical sticky traps compared with either type of unbaited trap. In cotton, baited red cylindrical traps captured more males than unbaited traps after 1 week of field exposure, but not after 2 weeks of deployment. Overall, red cylindrical traps caught more L. hesperus males than white delta traps. Diminished trap captures during the second week of monitoring may be attributed to high temperatures in cotton that likely shortened the lure's longevity and windy conditions in both strawberry and cotton that may have decreased the effectiveness of the trap's adhesive. Additional work to clarify the lure's field longevity and distinguish various elements of trap design (e.g. colour, adhesive, and shape) may further increase the operational effectiveness of pheromone-baited traps for L. hesperus.

Aphids pose a significant threat to crop production, highlighting the need for sustainable pest management strategies. Plant-derived compounds are well-known as eco-friendly alternatives to synthetic pesticides. However, the role of methyl chavicol (MC), a phenylpropanoid found in several plant species, in inducing plant defence through exogenous application remains unexplored, despite its demonstrated insecticidal properties against various pests on direct exposure. This study aims to investigate the impact of exogenous MC applications on Brassica assessing performance and behaviour of Myzus persicae Sulzer (Aphididae) and its parasitoid Aphidius gifuensis Ashmead (Braconidae). Therefore, we assessed aphid survival and fecundity on MC-treated and untreated (control) plants using clip cages and evaluated behavioural responses through settlement and Y-tube olfactometer assays. Additionally, we conducted foraging and parasitism bioassays to examine performance of the natural enemy A. gifuensis on MC-treated plants. Our results showed that M. persicae exhibited higher fecundity on MC-treated plants compared to controls, indicating that MC treatment made the plants more favourable for aphid reproduction. Similarly, A. gifuensis demonstrated enhanced preference and parasitism behaviour towards MC-treated plants, suggesting that MC could help recruit the parasitoid. These findings suggest that MC may act as a modulator of plant defence, altering insect-plant interactions while maintaining compatibility with beneficial insects, offering a promising approach for Integrated Pest Management (IPM) programs in Brassica crops.

The distribution and abundance of insect pests are influenced by landscape structure and composition, particularly through modifications to biocontrol services and the proportion of suitable habitats within the landscape. In addition, pest populations are affected by agricultural practices at different landscape scales, ranging from field-by-field to area-wide. Our study focuses on one of the world's most invasive and polyphagous pests of fruits and vegetables: the Oriental fruit fly, Bactrocera dorsalis (Hendel, 1912) (Diptera: Tephritidae). We analysed how farmer practices, landscape composition, and mango varieties were related to B. dorsalis infestation in an insular tropical agroecosystem with disparate farming systems, where crop plots are of modest size and interconnected with various habitat types. Fruit infestations were regularly recorded during 18 months in different plots on all mango varieties of the study area. Agricultural practices were determined through semi-structured interviews and categorised according to the farm structure and practices related to B. dorsalis management. Landscape composition was determined from high-resolution satellite imagery and local surveys, and the area of landscape cover was calculated within a 500 m buffer around each sampled orchard plot. We demonstrate that both landscape and local factors influence the infestation indexes of B. dorsalis in mango orchards. At a landscape scale, B. dorsalis was favoured by habitat diversity, which probably provided complementary larval food resources and enabled populations to maintain throughout the year. On a local scale, individual farmers' practices had a significant influence on infestation indexes. The proportion of infested fruits was lower in plots managed by farmers who practised sanitation.