Journal of Pest Science最新文献

In response to growing concerns regarding the adverse environmental and health effects of synthetic pesticides, there has been a notable surge in the demand for plant-based bioinsecticides. Botanicals and essential oils (EOs) are emerging as promising alternatives that offer a safer and more sustainable approach to pest management. Nevertheless, the effectiveness of these natural insecticides is often hindered by their inherent instability under environmental conditions, high volatility, and susceptibility to thermal decomposition, which necessitates frequent reapplication and diminishes their practical utility. To address these challenges, innovative formulation strategies such as nanoemulsions, microemulsions, nanoencapsulation, and microencapsulation have been developed. These advanced approaches facilitate controlled release, enhance stability, and significantly improve the efficacy of botanical- and EO-based insecticides. By providing target-specific action, these formulations not only reduce the frequency of applications and lower dosage requirements but also minimize environmental contamination and enhance overall pest management efficiency. This review offers a comprehensive exploration of these advanced formulations, including the preparation and characterization of nano-/microemulsion and nano-/microencapsulate systems and the technical challenges associated with their characterization. This manuscript examines the efficacy of these formulations in pest management, focusing on their physical and chemical stability under various storage conditions. Additionally, it addressed the impact of these formulations on nontarget organisms and their potential phytotoxicity. Despite the promising results observed in controlled settings, there is a notable lack of field studies evaluating the suitability of these formulations for different crops and their effectiveness in diverse agricultural environments. This identified gap underscores the necessity for further research to validate the practical application of these technologies. This review also discusses the scalability and cost-effectiveness of these advanced formulations, providing insights into their potential for broader commercial adoption.

The fall armyworm (Spodoptera frugiperda) is an important pest of maize, and a key target of transgenic crops expressing Bacillus thuringiensis (Bt) insecticidal proteins. These exert a strong selective pressure, so susceptible plants (refuges) are planted together with the transgenic seed to lower such pressure. The system favored in North America is to mix Bt and non-Bt seed (refuge-in-a-bag, or RIB). However, South American farmers favor structured refuges, interplanting rows of Bt and non-Bt seed. Yet, the proportion of susceptible maize must be minimized to prevent yield losses, and flight distance before mating is considered the best way to gauge the adequate distance between non-Bt rows in structured refuges, which has been estimated through mark–release–recapture experiments. The aim of this study was to compare three marking techniques and three trapping systems in laboratory and field experiments. Results suggest conventional marking techniques were not completely innocuous to the moths. UV traps drastically overrode the effect of synthetic and natural pheromones, suggesting they may not reflect normal dispersion behaviors. Marking experiments may not provide reliable measures of flight distance, and although farmers tend to resist the RIB option the data suggests it should be enforced.

Coffee leaf miner (CLM) Leucoptera coffeella stands out as a primary insect pest of arabica coffee plants in some regions of Brazil. Coffee breeding for CLM-resistance has used the species Coffea racemosa as gene donor for C. arabica, resulting in the development of the resistant commercial hybrid ‘Siriema AS1’. However, no previous study has characterized the resistance type, and whether there is variation in the levels expressed in progenies of ‘Siriema’ to CLM. This study aimed to characterize the type, by antixenosis or antibiosis, and the levels of resistance in segregating progenies of ‘Siriema’ plants to CLM. Experiments were conducted under laboratory conditions with artificial infestation of CLM adults in oviposition cages, where dual-choice preference assays compared each tested ‘Siriema’ progeny with the susceptible commercial cv. Arara (C. arabica). A follow-up no-choice assay evaluated five selected ‘Siriema’ progenies on the development of CLM compared to cv. Arara. As main results, ‘Siriema’ progenies were equally susceptible to CLM oviposition, and were overall stimulant relative to cv. Arara. However, there was low CLM larval survival and injury intensity on the selected ‘Siriema’ genotypes, indicating moderate levels of antibiosis-resistance, while cv. Arara and one ‘Siriema’ progeny were moderately susceptible. These findings further our understanding on the type and levels of resistance in ‘Siriema’ genotypes, aiding in the development of resistant coffee hybrids and deployment of management strategies to CLM.

Frankliniella intonsa (Thysanoptera: Thripidae) is a significant invasive pest that can damage numerous plants and crops and spread the tomato spotted wilt virus. During the sunflower flowering period in the primary sunflower production area in China, F. intonsa-infested sunflower heads produce kernels with marked visual damage, including peel scratches, which reduce seed quality and profitability. In this study, the behavioral responses of F. intonsa to buckwheat and sunflowers were measured in a Y-tube. Meanwhile, gas chromatography-mass spectrometry was performed to determine the volatile components of inflorescences of both sunflower and buckwheat and the behavioral effects of these components were evaluated on F. intonsa in a Y-tube. The results revealed that sunflower leaves significantly repelled adults and nymphs of F. intonsa both in olfactometer bioassays. However, F. intonsa was significantly attracted by the volatiles from the leaves and flowers of buckwheat. Interestingly, F. intonsa adults preferred sunflower flowers over buckwheat flowers. Among the four kinds of sunflower flower volatiles selected, F. intonsa was attracted by two kinds of volatiles (γ-terpinene and (R)-( +)-limonene), while one volatile (β-pinene) had the effect of repelling F. intonsa, while among the four selected buckwheat flower volatiles, F. intonsa were attracted by three kinds of volatiles (α-caryophyllene, verbenone, octane). Finally, the field-trapping effect of buckwheat on F. intonsa was verified by a sunflower-buckwheat intercropping experiment. The results of this study provide a theoretical basis for the feasibility of intercropping with buckwheat and sunflower to control F. intonsa. Thus, buckwheat can be used as a trapping plant in fields to prevent F. intonsa invasion.

The stable fly, Stomoxys calcitrans, is a globally important pest causing stress, economic losses and transmission of pathogens in livestock. Control on commercial farms relies predominantly on the use of insecticides, with pyrethroids being the most frequently used class of insecticides in industrialised countries. Here, laboratory isolates were obtained from four dairy farms in Brandenburg (Germany) and tested for phenotypic resistance to deltamethrin in comparison to a susceptible reference isolate using topical application. Individual flies were subsequently genotyped using allele-specific real-time PCRs. Phenotypic resistance was observed in all four field isolates with resistance ratios between 46 and 119 compared to the susceptible laboratory strain. At position 1014 of the voltage-sensitive sodium channel, allele-specific PCRs detected the wild-type, kdr-his and kdr genotypes encoding leucine, histidine and phenylalanine, respectively. In the susceptible laboratory isolate, only the wild-type was identified. On the farms with very high LD₅₀ values, the kdr variant was most prevalent and logistic regression analysis revealed that the kdr variant increased the odds to survive exposure to deltamethrin more than the kdr-his genotype. Flies carrying two resistance alleles were less susceptible than flies that also carried one wild-type allele. In three out of four field isolates, the allele frequencies were significantly different from the expectations of the Hardy–Weinberg equilibrium suggesting ongoing selection. The data show that the phenotype can be largely explained by the kdr genotype and represent high frequencies of the L1014F kdr and L1014H kdr-his variants conferring high levels of resistance in northern Germany.

Due to their potential role in pathogen transmission, invasive mosquitoes pose considerable threats to human and animal health. Several studies have identified the most important ecological drivers mediating the establishment and spread of key mosquito species (e.g., Aedes aegypti, and Ae. albopictus), and made predictions for future distribution. We evaluated the effect of an exhaustive list of environmental predictors on the distribution of three invasive species in Hungary (Ae. albopictus, Ae. japonicus, and Ae. koreicus) by using the same standards for data collection based on citizen science observations. Current distribution maps of these species were generated from a 5-year survey, then were compared with various predictor maps reflecting climate, habitat type, food supply, traffic, and interspecific competition by using a boosted regression trees approach that resulted in a subset of variables with the strongest impact. The best predictor sets were used to predict the probability of occurrence of the focal species for the whole country, and these predictions based on citizen science were evaluated against the results of an independent recent field surveillance. We uncovered species-specific patterns and found that different predictor sets were selected for the three different species, and only predictions for Ae. albopictus could be validated with direct trapping data. Therefore, citizen science informed distribution maps can be used to identify ecological predictors that determine the spread of invasive mosquitoes, and to estimate risk based on the predicted distribution in the case of Ae. albopictus.

The Fall Armyworm, Spodoptera frugiperda, invaded China late in 2018 and was responsible for substantial crop losses, especially to maize. This work focuses on the suitability of climate across China for Fall Armyworm survival and spread. It uses climate metrics derived with guidance from experts to enable assessment of the risks posed by Fall Armyworm on maize production in different regions of China. The locations and time of year when temperature conditions are within a viable range for Fall Armyworm survival (minimum temperature higher than 9.7(^circ)C and maximum temperature lower than 39.2(^circ)C) are used to estimate the spatial distribution of winter breeding and overwintering zones, which helps understand the regions and timing of Fall Armyworm migration risk into northern maize production regions. In addition, meridional wind conditions across the Yangtze River basin area are assessed, and a metric of migration potential from the winter breeding and overwintering regions in the south towards northern regions with maize production is established. Results show that temperature during the winter months currently limits Fall Armyworm winter breeding populations to the very southern regions of China (and bordering countries to the south). However, due to the consistent timing and direction of the East Asian Summer Monsoon winds, the Fall Armyworm could easily be directed northwards to the Yangtze River basin during summer months with a peak in July. For this reason, pest management actions against the Fall Armyworm on summer maize should be taken.

Phosphoinositide-dependent kinase PDK, a key component of the insulin signaling pathway, plays an important role in the regulation of insect growth and development. However, the functional significance of the PDK gene in Tuta absoluta, a destructive invasive tomato leaf miner, remains unknown. In this study, we identified and characterized a PDK gene (designated TaPDK) and analyzed its physiological roles in molting and reproduction of T. absoluta. Our results showed that the TaPDK expression levels were elevated in the 5- and 6-day-old pupae before ecdysis and declined immediately after eclosion. TaPDK was predominantly expressed in the head, midgut and abdomen. When the TaPDK was knockdown, the larval-pupal molting and female reproduction were severely affected. Injecting dsRNA of TaPDK into 2-day-old female pupae resulted in severe phenotypic changes (cuticular shrinkage) in 31.29% of pupae, ultimately leading to death. Knockdown of TaPDK significantly reduced the 20E titer and chitin content and downregulated the expression levels of genes involved in the 20E pathway and chitin metabolism. Further investigation revealed that the suppression of TaPDK impaired ovarian development, resulting in significantly reduced fecundity and hatchability. In addition, the JH titer and vitellogenin content of TaPDK-deficient females were reduced, and the expression of Vg, VgR, and JH signaling pathway genes were significantly decreased. Collectively, our study provides a deep insight into the PDK-mediated regulation of pupal ecdysis and female reproduction in T. absoluta.

The egg parasitoids, Trichogramma evanescens Westwood and T. pinto Voegelé (Hymenoptera: Trichogrammatidae), play central roles in the management of lepidopteran crop pests. However, their effectiveness highly depends on the employment of compatible pesticides, with a particular focus on novel insecticides that are promising in pest control. This study investigated the lethal, sublethal and transgenerational effects of two novel insecticides, afidopyropen and broflanilide, on T. evanescens and T. pintoi in terms of biological and behavioral traits. The eggs of the factitious host, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), with parasitoids at the preimaginal developmental stages (egg-larval, prepupal and pupal) were immersed in insecticide solutions. The emergence rates of both parasitoids were negatively affected by preimaginal treatments with different concentrations of afidopyropen and broflanilide. In transgenerational experiments, broflanilide treatments significantly reduced the parasitism performance of the treated generation (F0), emergence rate of F1 and F2, sex ratio of F1 T. evanescens and the emergence rate and sex ratio of F1 T. pintoi. Afidopyropen treatments reduced the emergence rate of F3 T. evanescens adults. The longevity of the F0 females and males of both parasitoids and that of the F1 females of T. evanescens were significantly reduced by broflanilide treatments. Broflanilide also decreased the walking speed of both species while afidopyropen enhanced the resting frequency of T. evanescens. This comprehensive study provides insights into the toxicological assessment of afidopyropen and broflanilide on Trichogramma species, employing parameters corresponding to their population and behavioral dynamics. Finally, this study concludes that the integration of afidopyropen and broflanilide into integrated pest management (IPM) strategies necessitates careful consideration, particularly regarding potential non-target effects on Trichogramma species.

The papaya mealybug, Paracoccus marginatus, is an invasive pest that causes significant damage to various tropical fruits and ornamentals worldwide. Lambda-cyhalothrin, an effective insecticide in integrated pest management (IPM) strategies, can control P. marginatus. This study evaluated the sublethal effect of lambda-cyhalothrin on the life table parameters and the detoxification enzymes activities of P. marginatus. Furthermore, transcriptome sequencing analysis revealed the potential mechanisms of the detoxification-related genes associated with enzymes activities. The study reported that lambda-cyhalothrin showed high activity against P. marginatus, with LC₃₀ values of 8.98 mg/L. Two-sex life table results showed that the development duration of the second instar nymphs, preadults, and adult female longevity was significantly prolonged, and the fecundity was stimulated in the F₁-CY of P. marginatus when the parental generation was exposed to LC₃₀ lambda-cyhalothrin. Moreover, lambda-cyhalothrin treatment significantly increased the activities of Cytochrome P450 monooxygenases (P450) and glutathione-S-transferase (GST) enzymes. Additionally, significant expression levels of P450, GST, carboxylesterase, and esterase genes were observed in P. marginatus subjected to the sublethal lambda-cyhalothrin exposure. Our findings demonstrate that sublethal concentrations of lambda-cyhalothrin influenced the development and fecundity of P. marginatus, and changes in enzymes activities and differential expression of detoxifying genes might be involved in the response and detoxification metabolism of lambda-cyhalothrin in P. marginatus. These results could contribute to a comprehensive risk assessment and provide guidance for the scientific use of lambda-cyhalothrin in IPM strategies.