Journal of economic entomology最新文献

Global climate warming is characterized by an escalation in extreme high temperatures (EHTs). While the frequency of EHTs is predicted to increase under climate change, there remains a limited understanding of whether maternal exposure to altered EHT frequencies affects maternal provisioning and next-generation phenotypic traits in insects. In this study, we investigated the influence of exposure to varying frequencies (either 1 or 5 peak-temperature days every 10 d, with a peak temperature of 34 °C) of EHTs on reproductive decisions and offspring traits in Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae). Our results revealed that M. sexmaculatus females exposed to a high frequency of EHTs exhibited a decrease in fecundity, alongside an increase in the proportion of non-viable eggs. Furthermore, maternal ladybirds experiencing a high frequency of EHTs could increase their offspring's body size. Offspring reared under a high-frequency EHT treatment displayed an extended larval development period, decreased egg laying, and a higher proportion of non-viable eggs. However, egg weight, egg clutch number, and egg clutch size in both maternal and offspring generations were unaffected by the increased frequency of EHTs. Our findings indicate that increased frequency of EHTs can generate modification in both maternal and offspring phenotypic traits, suggesting that adaptation to such conditions may occur through maternal effects. This research represents an essential step toward understanding the impact of maternal effects on the phenotypic traits of M. sexmaculatus in response to varying frequencies of EHTs and may further enhance our understanding of M. sexmaculatus population dynamics under future climate scenarios.

Within the past 4 decades, the 2 invasive and destructive subterranean termites, Coptotermes formosanus Shiraki and Coptotermes gestroi (Wasmann), have established in and spread throughout Florida. Monitoring efforts, initiated in the early 1990s, have substantially expanded in the past decade, providing improved resolution of where the 2 species have increased their distribution, allowing for the determination of which communities are most at risk of infestation by either species. This study provides insights on the outcome of the "Florida Termite ID Services" program, which has involved a growing number of participating pest control companies across the state over the years. Thanks to this enhanced monitoring effort, there is now concrete evidence that the Formosan subterranean termite (C. formosanus) has established in most Florida coastal counties and within most large urban areas across the state. Contrary to initial expectations, the Asian subterranean termite (C. gestroi) has established in new localities beyond South Florida, where it was initially restricted, now impacts a growing number of communities. In South Florida specifically, the initial projection that 50% of the metropolitan area will likely be at risk of infestation by either termite species by ∼2040, remains valid. This study highlights the importance of monitoring the spread of these 2 invasive species in partnership with pest control providers, so as to continue to bring awareness of the growing termite risks to exposed communities.

The cowpea aphid, Aphis craccivora (Koch), is a significant agricultural pest that globally affects numerous crops, leading to substantial yield losses through both feeding and the transmission of viral diseases. Flupyradifurone has an excellent safety profile and a unique mode of action; resistance to flupyradifurone has been reported in certain aphid species. In the current study, the cross-resistance and resistance mechanisms of A. craccivora to flupyradifurone were investigated. The results revealed that A. craccivora developed a resistance ratio (RR) of 46.6-fold as a result of laboratory selection for 28 consecutive generations. In the flupyradifurone-resistant strain (R-strain), metabolic enzyme determinations indicated significant increases in cytochrome P450 monooxygenase, esterase, and glutathione S-transferase activities. Moreover, quantitative real-time PCR (RT-qPCR) revealed the differential expression of CYP6DA2 and CYP380C6, with CYP6DA2 being upregulated, suggesting its pivotal role in flupyradifurone resistance. Molecular docking studies demonstrated a stronger binding affinity of flupyradifurone to CYP6DA2 than to CYP380C6, further supporting its involvement in detoxification processes. The findings also highlighted moderate cross-resistance to malathion, underscoring the need for insecticide management to mitigate the evolution of resistance. This study provides critical insights into the biochemical mechanisms underlying flupyradifurone resistance in A. craccivora and emphasizes the importance of developing effective resistance management strategies for pest control.

Spotted-wing Drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), is a damaging insect pest of sweet cherry fruit worldwide including in the central valley of California where it was first reported as an economic pest in spring 2009. The aim of this field-based study was to assess the relationship of Brix level and skin firmness on D. suzukii oviposition and infestation in 4 commercially important sweet cherry cultivars: Bing, Black Tartarian, Brooks, and Rainier. Results of this field study found that both higher Brix values and lower skin firmness resulted in increased fruit infestation in all varieties, highlighting the importance of these factors in host susceptibility. Other potential factors are also discussed as they relate to D. suzukii fruit infestation. Implications of these findings are discussed as well as how they might be used in future D. suzukii management in sweet cherries.

Many species of stored product insects have been spread by commerce, a few recently enough to have a written record. The bean weevil, Acanthoscelides obtectus (Say), Mediterranean flour moth, Ephestia kuehniella (Zeller), and Angoumois grain moth, Sitotroga cerealella (Olivier), have some of the most complete early records. The larger black flour beetle, Cynaeus angustus (LeConte) may have the most complete record of both geographic and host range expansion. The introduction of heated buildings and storage sites has allowed tropical species to establish in temperate climates. The adoption of combine harvesting has increased the prevalence of insect pests requiring grain damage such as the saw-toothed grain beetle, Oryzaephilus surinamensis (L.). Relatively few pest introductions result in establishment, but repeated introductions are common, increasing the chances of establishment. Preharvest infestation, diapause, and survival on food residues in the grain marketing system and other foods in natural habitats have increased the likelihood of establishment. Introduction of containerized shipping in the late 1960s may have reduced cross infestation of cargoes, provided containers were fully disinfested prior to loading. Remote monitoring may be necessary as an alternative to opening each container for early detection of infestations. The importance of limiting importation of pesticide resistant strains is mentioned often but there are few papers on practical implementation of such programs. Movement of natural enemies with stored commodities is common and this has resulted in their wide geographical distribution. Knowledge of geographic and host range expansion can be important for development of quarantine and pest management programs.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a major pest of soft-skinned fruits, with its strong reproductive capacity and adaptability rendering chemical control methods ineffective and environmentally risky. Biological control using parasitoid wasps is a sustainable alternative. This study focused on the larval parasitoid Leptopilina japonica Novković & Kimura (Hymenoptera: Figitidae) and 2 pupal parasitoids, Trichopria drosophilae Perkins (Hymenoptera: Diapriidae) and Pachycrepoideus vindemmiae Rondani (Hymenoptera: Pteromalidae), to evaluate their individual and combined effects on the control of D. suzukii. Experiments were conducted across a range of host densities (5 to 30 individuals per blueberry fruit) and different host patch types (within blueberries or as exposed pupae). The study measured offspring production, host stinging without oviposition-induced mortality, and total host mortality caused by the parasitoids. The implications for biological control of D. suzukii were also evaluated. The results showed that the parasitic efficiency of all 3 parasitoid species increased with host density, but L. japonica caused significantly higher mortality at high densities (≥20 hosts) compared to the pupal parasitoids. Trichopria drosophilae and P. vindemmiae exhibited stable performance in pupal parasitism, with P. vindemmiae showing stronger adaptability to concealed hosts. Population suppression experiments demonstrated that the combined release of L. japonica and T. drosophilae achieved the optimal control effect, significantly reducing the number of D. suzukii adults after 45 d compared to the control group, while also promoting significant population growth of the parasitoids. This study demonstrates that the combined release of larval and pupal parasitoids can significantly enhance control efficiency against D. suzukii.

Bumblebees are efficient pollinators of fruits and vegetables in greenhouses and field crops. However, pesticide use in agricultural landscapes is causing a sharp decline in pollinating insect populations. The impact of pesticides on bumblebee health is a growing concern. Cyfluthrin, atrazine, and prothioconazole are 3 commonly used pesticides in agricultural production. Although the Food and Agriculture Organization of the United Nations has published the acute median lethal dose (LD50) data for these 3 pesticides on Apis mellifera honey bee, there is still a lack of LD50 data for non-Apis bees, such as Bombus terrestris (Linnaeus, 1758). Therefore, this study determined the oral median lethal dose (LD50) of 3 pesticides, cyfluthrin, atrazine, and prothioconazole, in European bumblebees (Bombus terrestris). The active ingredient of each pesticide was first dissolved in dimethyl sulfoxide and then diluted in a sucrose solution to prepare the pesticide-sucrose mixture for feeding. The oral LD50 values of cyfluthrin for worker bees were 4.27, 3.36, and 2.16 μg/bee at 24, 48, and 72 h, respectively. The 24-h LD50 for virgin queens was 13.49 μg/bee. For 24-h exposures in worker bees, the oral LD50 values of atrazine, prothioconazole, and their mixture were 355.3, 530.0, and 480.4 μg/bee, respectively. Pesticide-sucrose solution intake decreased as pesticide concentration increased. This study provides a preliminary evaluation of the toxicity of 3 pesticide types on bumblebees and offers insight for improving the conservation and sustainability of pollinators in agriculture. Additionally, the findings contribute to regulatory assessments by providing crucial data on pesticide effects on B. terrestris, supporting more comprehensive and effective pesticide regulations.

Dust formulations are important alternatives for bed bug control, yet their efficacy against tropical bed bugs (Cimex hemipterus (F.)), which frequently exhibit pyrethroid resistance, remains poorly defined. We evaluated 2 desiccant dusts (CimeXa, diatomaceous earth [DE]) and 2 chemical dusts (DeltaDust, Drione) against 3 pyrethroid-resistant C. hemipterus strains with documented cuticle variation and compared them with a susceptible Cimex lectularius L. (Monheim). Bioassays simulated continuous exposure, brief (5 min) contact, sublabel (50% rate) application, and horizontal transfer. Desiccant dusts, particularly CimeXa (silica), consistently achieved rapid and complete mortality in resistant C. hemipterus, outperforming DE and pyrethroid-based dusts. Chemical dusts were more constrained: DeltaDust (deltamethrin) was largely ineffective, while Drione (pyrethrin + PBO + silica gel) killed susceptible C. lectularius rapidly (<1 h) but was markedly slower in resistant C. hemipterus, reflecting kdr mutations and cuticle-mediated tolerance. Reduced dosage and brief exposure prolonged survival times, and horizontal transfer produced the greatest delays, although both pathways ultimately resulted in high mortality. Strain comparisons revealed a susceptibility hierarchy (SEL_MY > PEN2_MY > KUL_MY), consistent with cuticle thickness, indicating that thickened cuticles delay desiccant activity under direct exposures. Importantly, the effect of cuticle thickness was minimized for CimeXa under horizontal transfer but persisted for Drione. By linking exposure dynamics with kdr and cuticle-mediated resistance, this study shows that chemical dusts remain strongly constrained by resistance mechanisms, whereas silica-based desiccants-despite delayed action in strains with thickened cuticles-retain superior reliability and represent the most effective dust formulations for sustainable bed bug management.

Management of sugarcane stem borers (Diatraea spp.) in Colombia's Cauca River Valley (CRV) relies mainly on biological control. Augmentative releases of biocontrol agents are guided by damage assessments (percentage of internodes bored) at harvest and then scheduled accordingly for the next crop cycle. A more proactive monitoring method conducted during the current crop cycle could improve correspondence between natural enemy releases and actual pest pressure. Between 2013 and 2015, 644 commercial fields were sampled for larvae using a standardized 2 person-hour effort per field less than 3 mo post-emergence. Injury data (% of internodes bored) were also collected at harvest from 535 of these fields between 2014 and 2015, 348 before, and 187 after, larval sampling. The relationship between early larval counts and at-harvest damage was analyzed using geostatistical tools and Median tests. Larval counts ranged from 0 to 48 per unit of sampling effort, whereas damage ranged from 0% to 22% of internodes. The highest larval counts and injury levels occurred in northern and central CRV. Larval counts at 3 mo post-emergence were correlated with at-harvest damage in the previous crop: fields with 4% of internodes bored at harvest had a high probability of exceeding ≥30 larvae per sample in the subsequent crop. These results suggest that early season counts of ≥30 larvae per 2 person-hour sampling effort might represent a useful threshold for initiation of biocontrol augmentation programs.

Spruce beetle, Dendroctonus rufipennis (Kirby) (Coleoptera: Curculionidae), is the most significant pest of spruce, Picea spp. (Pinales: Pinaceae), in western North America. Several doses of 3-methylcyclohex-2-en-1-one (MCH), the primary antiaggregation pheromone of D. rufipennis, alone and combined with non-host volatiles have been demonstrated effective for Picea protection. Herein, we evaluate the effects of MCH dose on D. rufipennis captures in baited trapping assays in Alaska and Colorado, United States. Twenty-five, 12-unit, multiple-funnel traps were baited with a D. rufipennis lure (frontalin + MCOL + spruce terpenes; Synergy Semiochemical Corp., Delta, British Columbia, Canada) and randomly assigned to one of 5 treatments in each assay: SBL (baited control); SBL + 1 g MCH; SBL + 3.5 g MCH; SBL + 7 g MCH; and SBL + 10 g MCH. SPLAT MCH (experimental formulation ISR: MCH-001R1, ISCA Inc., Riverside, California, United States), a flowable matrix containing 10.0% MCH by weight, was used in both assays with dose manipulated by the number and size of SPLAT MCH dollops (release points) attached to traps. In both Alaska and Colorado, all MCH doses (1, 3.5, 7, and 10 g) significantly reduced D. rufipennis captures compared to SBL. No significant differences were observed among MCH doses. Males and females responded similarly to MCH doses. The implications of these and other results to management of D. rufipennis are discussed.