Journal of economic entomology最新文献

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.

Frankliniella occidentalis (Western flower thrips; WFT) is an important pest of vegetable and flower crops. The development and application of plant-induced resistance and RNA interference (RNAi) technology are environmentally sustainable and promising approaches in pest control research. This study verified the regulatory role of digestive enzyme genes in the adaptation of WFT to jasmonic acid (JA)-induced defense responses in Phaseolus vulgaris (kidney bean) plants. First, 4 digestive enzyme-encoding genes were cloned and identified. Subsequently, their expression patterns during different developmental stages were analyzed. Second, the mRNA levels of these genes were analyzed in the F0 and F1 generation female adult WFT that fed on leaves from JA-induced bean plants. The results showed that the expression of FoαAmy1 (α-amylase gene) and FoEG1 (endoglucanase gene) was significantly upregulated during the adaptation of WFT to the JA-induced defense response in kidney bean plants. RNAi and bioassay results indicated that silencing FoαAmy1 and FoEG1 significantly reduced the survival rate and feeding damage caused by adult WFT that fed on JA-induced kidney bean plants. Overall, FoαAmy1 and FoEG1 may be involved in regulating the adaptability of WFT to JA-induced defense responses in kidney bean plants.

The novel meta-diamide insecticide cyproflanilide is highly effective on the rice stem borer, Chilo suppressalis (Lepidoptera: Pyralidae). Nevertheless, the sublethal effects on key natural enemies, such as Cotesia chilonis (Hymenoptera: Braconidae), remain unexplored, which is critical for ecological compatibility within IPM programs. We investigated the direct and indirect effects of sublethal doses of cyproflanilide on C. chilonis. Our results revealed that the LC50 of cyproflanilide on female and male wasps of C. chilonis were 1.17 mg/L and 0.37 mg/L, respectively. After treatment of C. suppressalis with cyproflanilide, they were then parasitized by C. chilonis. Compared with control groups, the cyproflanilide treatment showed no significant differences in the number of cocoons, total number of emerged wasps (including males and females), or the parasitism rate of C. chilonis. In contrast, when C. chilonis was exposed to cyproflanilide at LC30 concentration, no significant alteration in developmental duration was observed compared to the control group. The number of cocoons by C. chilonis decreased from 47 to 34. Similarly, the number of emerged wasps decreased from 47 to 31, and the parasitism rate decreased by 9%. Our results show that the indirect effects of cyproflanilide on C. chilonis were not significant; direct contact with the insecticide poses significant risks to the C. chilonis reproductive output. Thus, it can be seen that when applying pesticides in the field, it is necessary to stagger the emergence peaks of C. chilonis and C. suppressalis, which is important for the prevention and control effect.

Tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is one of the most consistent pests of cotton in the southeastern United States. Tarnished plant bug primarily feeds on reproductive structures, including pre-floral buds (squares), flowers, and small bolls, but can also feed on apical meristem tissue during pre-floral stages. Damage to cotton terminals can lead to loss of apical dominance and irregular cotton growth, potentially reducing lint yield. In 2022 and 2023, trials were conducted in 5 southeastern United States states (ie Virginia, North and South Carolina, Georgia, and Alabama) to determine the impact of simulated terminal injury at the 7-node stage and the fourth week of squaring on cotton growth and lint yield. Terminal injury at the fourth week of squaring led to a reduction in plant height or plant canopy width at the end of the season in several trials. Despite changes in plant architecture occurring in some trials, cotton lint yield was rarely affected by early terminal removal, except for the latest planted trial across the 2 study years. This provides limited evidence which further emphasizes the importance of timely planting for cotton in the southeastern region. The current study demonstrates the limited impact that terminal injury has on cotton lint yield and will help shape management recommendations for pre-floral cotton in the southeastern cotton production region.

The floriculture and nursery industry is a key contributor to Hawaii's economy, with ornamental crop exports, particularly cut flowers, accounting for a significant portion of sales. However, pest-related shipment rejections have increasingly threatened market access. As a first step to develop an effective systems approach for maintaining market access, we analyzed California interception records from 2012 to 2016, which revealed 582 cut flower shipment interceptions from 92 Hawaiian growers and shippers, with rejections primarily due to ants, aphids, mealybugs, and scale insects for non-orchid cut flowers (eg ginger and heliconia) and thrips for cut orchid flowers (eg Dendrobium). For targeted trials of ginger and heliconia, the effect of sequential pre-harvest (systemic insecticide spraying and ant baiting) and postharvest treatments (washing, hot water treatment, and second washing) were evaluated under commercial conditions. While individual treatments alone did not achieve complete disinfestation of ginger and heliconia, combining them as a systems approach led to zero detectable infestation across 8 harvests during the second year of the study, indicating this may be a feasible phytosanitary strategy for Hawaii-grown cut flowers. In contrast, for Dendrobium orchids with limited postharvest treatment options, pre-harvest insecticide programs were ineffective for managing thrips, with 30% of Dendrobium flowers and 70% of the flower sprays remaining infested post-insecticide treatment, highlighting the need for improved thrips management and the potential for integrating with postharvest fumigation. Overall, our results demonstrate the potential of systems approach in reducing pest interceptions and supporting continued access of Hawaii-grown cut flowers to US mainland and international markets.