Journal of economic entomology最新文献

Cold treatments are widely used for disinfestation of commodities in international trade and mostly require an uninterrupted duration of exposure to temperatures that do not exceed a specified threshold. The effect of temporary interruptions on cold treatment efficacy was tested on second instar larvae of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in Valencia oranges. In a first series of experiments using one room, a cold treatment of 6 d at a target pulp temperature of 0.9 °C was used. When applied continuously, this constituted the uninterrupted treatment. Interruptions to this treatment were simulated by removing fruit from the cold room until pulp temperatures reached either 3.1 °C or 5.1 °C and as soon as these were reached, fruit were brought back. The timing (first or second half), intensity (3.1 °C or 5.1 °C) and frequency (single or double) of interruptions were investigated in this series. In a second series of experiments using 2 cold rooms at a target pulp temperature of 0.9 °C, interruptions were induced by switching off cooling in one of the cold rooms until pulp temperature reached 5.1 °C. Once the latter was reached, cooling was switched on again. The total interruption time was at least 33 h with a minimum of 16 h for pulp temperatures to reach 5.1 °C and a minimum of 17 h for return to target temperature. In experiments conducted for either 6 or 14 d, there were no significant differences in larval mortality between interrupted and uninterrupted treatments. This study demonstrated that cold treatment efficacy was not compromised by temporary temperature interruptions.

Mythimna separata is a major migratory agricultural pest in China, with its number of generations varying significantly along latitudinal gradients, posing a serious threat to grain production and security. To address the current lack of fundamental temperature-response data for predicting outbreaks in third-generation occurrence areas, this study systematically investigated the developmental characteristics of this pest under naturally fluctuating temperature conditions. Three complete generations were observed during the April-October 2021 study period, with each generation's developmental progression showing a significant correlation with temperature variations. The second generation developed fastest during the high-temperature period in July, completing its life cycle in only 48.2 d. When the temperature reached approximately 25 °C, the developmental duration shortened significantly, but the larval survival rate decreased. Fifth-instar larvae exhibited the strongest environmental adaptability, with starvation tolerance lasting up to 281.4 h. This study provides guidelines for predicting M. separata occurrence in third-generation breeding areas under natural conditions.

The sweetpotato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is an important pest of many horticultural crops. Due to resistance development, whiteflies are difficult to control using chemical pesticides. This study aimed to explore the use of light-emitting diodes (LEDs) of different wavelengths, from near-ultraviolet to near-infrared (375, 470, 500, 525, 570, 660, and 850 nm), to trap B. tabaci adults. Seven LED panels and one non-lighting panel with transparent adhesive sheets were installed in a greenhouse where B. tabaci adults (biotype Q) were released. The number of B. tabaci adults trapped on the adhesive sheets after irradiation was counted. These experiments were conducted in summer and winter, during daytime and nighttime. In the summer experiment, B. tabaci adults were most frequently trapped at 525 nm (green) and 375 nm (ultraviolet A [UVA]) during the daytime and nighttime, respectively. In the winter experiment, B. tabaci adults were most often trapped at 525 nm during the daytime, although the numbers were very low, possibly due to their low density in the greenhouse. In the winter nighttime experiment, B. tabaci adults were not trapped at any wavelength, regardless of heating. In conclusion, 525 nm LED light (green) during the daytime and 375 nm LED light [UVA] during the nighttime may be used to attract B. tabaci (biotype Q) adults. LEDs that attract specific pests may be applied not only for pest control but also for monitoring. This study may serve as a basis for the use of LEDs in strengthening integrated pest management programs.

Certain invasive ambrosia beetles are attracted to and colonize physiologically stressed trees emitting ethanol. Xylosandrus germanus (Blandford) and Xylosandrus crassiusculus (Motschulsky) are attracted to trees emitting ethanol and are 2 of the most damaging invasive ambrosia beetles in North America. Acetic acid has been detected in stressed trees emitting ethanol, but whether it has a role in ambrosia beetle ecology is unknown. Sections of tree stems (bolts) were soaked in various dilutions of acetic acid alone and mixed with a 5% dilution of ethanol, then deployed in a field near a woodland. Bolts soaked in 5% or 10% dilutions of acetic acid were more attractive to X. germanus and X. crassiusculus than bolts soaked in dilutions of 0.1% or 1.0%. Dilutions of acetic acid mixed with 5% ethanol were more attractive to X. germanus and X. crassiusculus than similar dilutions of acetic acid alone or 5% ethanol alone. Furthermore, more offspring were produced in bolts soaked in mixtures of acetic acid and 5% ethanol than either compound alone. This information helps improve our knowledge of the physiological conditions in trees that make them suitable for colonization by X. germanus and X. crassiusculus. Furthermore, the increased attraction of damaging ambrosia beetles to acetic acid + ethanol could be useful for improving baits used for monitoring emergence of X. germanus and X. crassiusculus in spring.

Little research has examined whether consistent levels of insect herbivory over multiple years affect plant composition in grasslands. We conducted a 7-yr manipulative experiment at a northern mixed-grass prairie site in eastern Montana, examining native grass cover in relation to herbivory by 2 grasshoppers with different feeding modes. The objective was to examine whether sustained levels of herbivory by 2 grasshopper species over 7 yr affected basal cover of the dominant grass species, western wheatgrass and blue grama. Blue grama cover was approximately 50% lower at the end of the experiment with a grass feeder Ageneotettix deorum (Scudder) relative to treatments without herbivory and with a mixed grass and forb feeder Melanoplus sanguinipes (Fabricius). The results appear to be driven by plant preference and feeding behavior, as A. deorum damaged blue grama blades more frequently. Although vertebrates typically have stronger impacts on rangeland plant composition, blue grama appears less resistant to herbivory by grass-feeding grasshoppers than cattle grazing in this mixed grass prairie. The results point to the need for further research on how grasshopper feeding mode affects rangeland function.

Accessible and accurate methods of pest identification are a cornerstone of pest management. When identifications are not feasible using morphology, molecular methods such as DNA Barcoding provide an option to complete a diagnosis. However, previous studies have shown that some pests cannot be identified to species using DNA Barcodes. In such cases, a genus-level identification could guide subsequent response to pests, but few studies have examined the performance of DNA Barcoding methods to diagnose pest genera as opposed to pest species. We datamined 6,582 previously published Cytochrome C Oxidase I (COI) Barcode region sequences for 12 genera of tephritid fruit flies that include the six main pest genera. After filtering short sequences and duplicate haplotypes, a dataset with 3,077 sequences remained for a pairwise-distance and tree-based genus-level identification test. Our results show that a 5% pairwise distance threshold provides reliable genus-level identifications using sequences of 400 to 658 base pairs. This threshold can easily be implemented with widely available tools such as the Basic Local Alignment Search Tool (BLAST) algorithm. The 5% distance cutoff value is set conservatively and could be refined further by including more species and genera in the reference set. We additionally find that the 3՛ end of the COI Barcode region has greater pairwise distances between genera than the 5՛ end. Our findings provide an additional use of the COI Barcode region for identification that can readily be implemented in pest fruit fly management protocols.

Codling moth (CM), Cydia Pomonella, is a major challenge for apple growers worldwide due to the decrease in registered insecticides, rising resistance, and climate change, highlighting the need for sustainable management solutions like the Sterile Insect Technique (SIT) and grower-informed outreach strategies. We surveyed 76 Virginia apple growers to assess their familiarity, perceptions, and information needs related to SIT, and factors influencing their likelihood of adopting a new CM management technique. We collected data at four extension grower meetings and used descriptive statistics and logistic regressions for analysis. Over one-third of respondents reported increased CM damage over the past 5 years and were concerned about management. Compared to respondents with low concern, those with high concern were 25.32 times more likely to adopt a new management technique. Most had positive attitudes toward SIT and agreed it could result in various benefits, including reduced pesticide use and reduced resistance development. Respondents who perceived greater benefits were 15.61 times more likely to have positive attitudes toward SIT compared to those who perceived fewer benefits. Potential barriers to adoption included uncertainty about SIT effectiveness and cost. Respondents identified grower case studies, research on SIT, and information on cost-effectiveness as the most helpful information types. They preferred learning about SIT through field demonstrations and extension personnel. These results suggest growers are receptive to SIT and highlight the importance of outreach strategies that incorporate social science methods to address concerns, emphasize benefits, showcase grower experiences, promote experiential learning, and leverage trusted sources to support adoption.

SPLAT GM-Organic, a controlled-release pheromone formulation, has been used since 2008 in an area-wide integrated pest management program targeting spongy moth, Lymantria dispar (Linnaeus) (Lepidoptera: Erebidae). In 2018, a noticeable decline in treatment performance raised concerns about potential changes in droplet characteristics affecting pheromone release and field longevity. To explore this, we evaluated the field efficacy of 3 SPLAT GM-Organic formulations applied in 2018, 2020, and 2021, and analyzed their droplet size distributions. Droplets were grouped into biologically meaningful diameter categories, and their proportions were examined using multivariate analyses and regression modeling. The findings indicate that efficacy and longevity were strongly influenced by droplet composition. Formulations containing higher proportions of large and ultra-large droplets achieved greater mating disruption and remained effective longer in the field. In contrast, formulations dominated by smaller droplets showed reduced performance. These results highlight the critical role of droplet size distribution in determining the success of SPLAT GM-Organic formulations. The ability to adjust droplet profiles through formulation design offers a practical strategy to improve the reliability and consistency of mating disruption treatments against spongy moth. More broadly, because SPLAT is widely used as a matrix for pheromone-based pest control in a variety of systems, these findings may inform formulation development and quality assurance efforts in other programs as well.

Odontotermes formosanus (Blattodea: Termitidae) is a social insect that significantly damages horticultural trees and water conservation infrastructure. Our previous studies confirmed that 1,2-dibenzoyl-1-tert-butylhydrazine (RH-5849) is toxic to O. -formosanus. However, insects have detoxification enzymes like cytochrome P450 (CYP) and glutathione S-transferase (GSTs) that can detoxify insecticides and mitigate their toxicity. To investigate CYP and GSTs in the defense of O. formosanus against RH-5849, we assessed the effects of the CYP inhibitor piperonyl butoxide and the GSTs inhibitor diethyl maleate on the toxicity of RH-5849 against O. formosanus. The results indicated that piperonyl butoxide and diethyl maleate significantly increased the lethality of RH-5849 to O. formosanus by 49.61% and 37.21%, respectively. Through RNA-seq and quantitative real-time PCR, OdfoCYP301A1 and OdfoGSTo1 were identified, with relative expression levels of 2.90 and 11.91, respectively. Moreover, we cloned OdfoCYP301A1 and OdfoGSTo1 and synthesized double-stranded RNA (dsRNA) based on these sequences. Furthermore, we evaluated the lethality of RH-5849 to O. formosanus following 24 h of dsRNA interference treatment. The results indicated a significant increase in the lethality of RH-5849 to O. formosanus following interference with OdfoCYP301A1 or OdfoGSTo1. These results suggest that OdfoCYP301A1 and OdfoGSTo1 play important roles in the defense of O. formosanus against RH-5849. Furthermore, this study provides new targets for the combined use of dsRNA and RH-5849 in the control of O. formosanus.

The arrangement of crop hosts in the landscape plays a role in polyphagous pest exposure to multiple chemical applications that can affect resistance selection. Stink bugs are a group of polyphagous pest species that utilize both crop and noncrop hosts throughout the growing season, leading to insecticide exposure in different crops. The spatiotemporal arrangement of common crop hosts creates a mosaic of host patches that are infested by stink bugs during the growing season in eastern North Carolina. This study explored the relationship between stink bug insecticide susceptibility and landscape composition in that region. Stink bug populations were collected from 35 locations from 2022 to 2024 in eastern North Carolina. A glass-vial bioassay procedure was used to evaluate bifenthrin susceptibility of Euschistus servus Say (brown stink bug), Chinavia hilaris Say (green stink bug), and Nezara viridula L. (southern green stink bug). We then used a geospatial approach to explore the relationship between insecticide susceptibility of stink bug species and landscape-level availability of host crops where bifenthrin is commonly used. Our results showed that in bifenthrin susceptibility differed among stink bug populations. Species level susceptibility was not consistently related to the abundance and frequency of their host crops. Stink bug susceptibility to bifenthrin reported here will provide the baseline data in future resistance monitoring programs.