Journal of Pest Science最新文献

(E)-ß-farnesene (EBF) acts as an alarm pheromone of many aphid species and is also used as an aphid repellent by plants. Upon perception of EBF, aphids exhibit avoidance behavior. They walk away, stop feeding or drop from leaves. Moreover, EBF is an attractant for natural enemies of aphids. However, EBF is not used in pest management because it is expensive in its pure form. Therefore, we assessed the effect of a less expensive farnesene isomer mixture (FIM) on Myzus persicae (Sternorrhyncha: Aphidiae) on lettuce (Lactuca sativa var. Ulmo) in the laboratory and under field conditions. First, we tested under laboratory conditions if FIM has the same effect on M. persicae as it is described for pure EBF. The aphids were influenced by EBF. They stopped feeding, withdrew their stylets, went away from the danger zone, or developed and reproduced more slowly. Therefore, we studied the behavioral response of the aphids after FIM application and aphid reproduction under permanent exposure of FIM. Second, we tested in the field the reaction to FIM either directly applied to lettuce or released by dispensers. In the lab experiments, we found that M. persicae reacts to FIM by walking away and that reproduction tends to be reduced in the presence of FIM. In the field, we found lower numbers of aphids in the treatments with FIM. In particular, dispenser application caused higher aphid reduction compared to spray application on lettuce. In addition, more natural enemies of aphids could be found in dispenser-treated plots. Taken together, these results indicate that the use of FIM could contribute to insecticide-free aphid control in lettuce, but possibly also in other crops.

Huanglongbing, a devastating citrus disease, is associated with ‘Candidatus Liberibacter asiaticus’, ‘Ca. L. africanus’ or ‘Ca L. americanus’, bacteria transmitted by the psylloids Diaphorina citri and Trioza erytreae. Using a DNA-Seq and metabarcode sequencing integrated approach, the first catalogue of endosymbionts associated with T. erytreae from the Iberian Peninsula, South Africa and African Islands, was generated. The almost complete genome of two new bacteria, one facultative and one obligate, tentatively named Asaia-like endosymbiont of T. erytreae and Sodalis-like endosymbiont of T. erytreae, respectively, was assembled and annotated. The complete mitochondrial genomes of T. erytreae from the geographical areas studied were also assembled and phylogenetic analyses were performed, suggesting that T. erytreae populations currently present in the Iberian Peninsula and specimens analyzed from South Africa may have originated from a common ancestor. Similar results were obtained when the genetic distances between Sodalis-like endosymbiont of T. erytreae were taken into consideration, thus supporting the symbiont–host codivergence which suggests that this bacterium is approaching to an obligate status. Finally, a new genetic marker of T. erytreae, an insertion in the mitochondrial tRNA-Ser gene, was identified only in some European samples, showing for the first time the existence of two mixed subpopulations of T. erytreae. The integrated DNA-Seq and metabarcode sequencing approach used in this study, besides generating a catalogue of T. erytreae endosymbionts, provided novel data on the sequence variability of bacterial and insect mitochondrial genomes from different geographic areas, highlighting the possible original sources of currently spreading T. erytreae populations may be more complex than previously reported.

Protaetia brevitarsis (Lewis, 1879) is a serious agricultural and forestry pest. Since first report in Xinjiang (XJ), China in 2001, it has rapidly spread. This study explored the phylogeographic structure of Chinese P. brevitarsis as well as the origin and dispersal route of the XJ population using COI and EF-1α gene-based analysis, geometric morphometrics, and the optimized maximum entropy (MaxEnt) model. The results indicated Chinese populations exhibit high genetic diversity. Spatiotemporal reconstruction of the geographic dispersal indicated P. brevitarsis initially moved from its origin in the Huang-Huai region (HH) to XJ through the Hexi Corridor during the late Pleistocene, approximately 0.135 million years ago (Ma). Before 0.02 Ma, reciprocal active dispersal events occurred between XJ population and others, leading to the formation of the current phylogeographic pattern. This aligns with the demographic history, P. brevitarsis experienced continuous and rapid population expansion from 0.075 to 0.006 Ma. Based on the Procrustes distance cluster analysis of shape variation of the white spots on the elytra, the populations of HH, XJ, North China, and SGN (including Shaanxi, Gansu, and Ningxia regions) exhibit high morphological similarity, supporting the molecular research that these geographic populations are closely related. MaxEnt indicated suitable habitats in western Inner Mongolia during the Last Interglacial and the Hexi Corridor during the Last Glacial Maximum, facilitating dispersal from eastern China to XJ. During the Mid-Holocene and the current period, the corridor for active dispersion cut off. Gene flow between XJ population and eastern populations may be attributed to passive dispersion resulting from agricultural trade. These results alter previous understanding of the origin and evolutionary history in XJ, and provide scientific evidence for differentiated control measures for different geographic populations of P. brevitarsis.

RNAi for insect control is a promising alternative to synthetic insecticides. Intense research efforts over the years have allowed researchers to develop effective control strategies and, recently, the registration of a new product for the US market. To date, however, the insect stages targeted by RNAi are both juveniles and adults, while the egg stage has been largely ignored, although an early suppression of the pest would more efficiently limit its damage. Here we try to fill this gap by focusing on the silencing of Sl102, a gene that encodes precursors of functional amyloid fibrils involved in the immune response and that, based on literature reports, could have an important role in the modulation of the embryonic development of lepidoptera. We showed that Sl102 is expressed throughout the embryogenesis of Spodoptera littoralis, showing a peak 32 h after oviposition. The transcription level of this gene is strongly reduced by RNAi induced by soaking the eggs in a dsRNA solution. Interestingly, gene silencing is associated with a drastic reduction in egg hatching rate, which is complemented by a very high mortality of the few hatched larvae. Structural and ultrastructural analyses showed a significant delay in the development of silenced embryos, which also exhibited morphological alterations. Our results expand the understanding of the Sl102 gene function, indicating an important role in embryonic development that remains to be studied from a functional point of view. This paves the way toward the future development of effective control strategies for S. littoralis, based on the suppression of embryonic development through RNAi technology.

The utilization of pest behavior modulators in conjunction with conventional synthetic insecticides has emerged as a novel approach to enhance the efficacy of these applications. This integration involves the promotion of insect movement or the attraction of insects to treated areas, thereby optimizing the performance of the entire mixture. The present study aims to assess the effect of nine pest behavior modulators on the walking behavior of Euschistus heros (3rd instar nymphs and adults) using the automated computational tracking system (Ethovision^®). The findings revealed that Quimifol S450^® increased the total distance covered and sodium chloride (kitchen salt) reduced the walking speed of E. heros adults. Furthermore, physicochemical compatibility assessments employing the dynamic technique (with agitation) indicated that binary mixtures of all insecticides tested with Quimifol S450^® considerably increased the pH of the spray solution. Conversely, binary mixtures of insecticides with Atraksii^® exhibited a substantial increase in electrical conductivity. Moreover, laboratory tests (tarsal contact) and field trials (for two consecutive crop seasons), employing two conventional synthetic insecticides and four pre-selected pest behavior modulators, as well as their respective binary mixtures, demonstrated that the performance of stink bug control was diminished when sulfur-based dislodger Quimifol S450^® was mixed with acephate. Furthermore, the pest behavior modulators exhibited low activity after 15 min of insect exposure to treated surfaces. Our findings imply that the integration of homemade and commercial pest behavior modulators and conventional synthetic insecticides should be approached with caution, as potential antagonistic effects may be observed.

By attracting and stimulating feeding on spray droplets, phagostimulant baits provide an opportunity to increase the efficacy of crop protection products against the spotted wing drosophila (Drosophila suzukii). Here, we examined the use of a high-sugar, plant-derived bait (ProBandz^®, PB) in combination with low dose insecticides and an entomopathogenic fungus Metarhizium anisopliae strain 35.79 for control of D. suzukii. We compared the efficacy of treatments in laboratory jar bioassays and in semi-field strawberry experiments using laboratory D. suzukii cultures, and in field strawberry and raspberry experiments on natural D. suzukii infestations. M. anisopliae 35.79 increased D. suzukii mortality in jar bioassays but did not affect oviposition. There was no evidence that combining M. anisopliae 35.79 with PB led to increased efficacy, and in a semi-field experiment this combination led to an increase in D. suzukii larvae in fruit. Deltamethrin in PB droplets was effective in increasing mortality and reducing oviposition in jar bioassays but deltamethrin + PB bait sprays were ineffective in a field raspberry experiment. PB increased the D. suzukii control efficacy of lambda-cyhalothrin in jar bioassays. Low volume bait sprays with 8% of the full field rate of lambda-cyhalothrin in semi-field and field strawberry experiments were as effective in controlling D. suzukii as full rate, high volume insecticide sprays but without causing pesticides residues in the fruit. This work will provide evidence supporting the reduction of dependence and risk of resistance to the two main insecticides used for D. suzukii control: spinosad and cyantraniliprole.

Crop losses are expected to increase due to the positive impact of rising temperatures on pest populations. Adapting pest control strategies to climate change is thus crucial for sustainable food production. This review examines the influence of climate, particularly temperature, on four common pest control tactics: chemical insecticides, pheromone-based mating disruption, entomopathogens, and biological control using entomophagous arthropods. The use of insecticides is likely to increase because of higher pest populations, but the effect of temperature on their toxicity is complex and varies between insecticides and pest species. Entomopathogens and their derivatives may also see improved efficacy, as higher temperatures enhance infectivity and pathogenicity, though the influence of climate on insect immune systems remains unpredictable. The effect of warming on insect biological control with entomophagous organisms is highly context-dependent because the outcomes depend on the relative thermal range of interacting species. Furthermore, the efficiency of biological control agents would be determined by changes in their physiology and behaviour, by the composition of their communities, and by cascading trophic effects. Potential improvements in pest management strategies would help to cope with climate change. For example, combining two or more biological control agents that have different thermal preferences, selecting strains adapted to harsh climatic conditions, or genetically improving them through selection have the potential to mitigate the overall positive influence of climate change on insect pests.

The United Nations (UN) has made strong commitments toward achieving the sustainable development goals (SDGs), aiming to alleviate food scarcity, reduce hunger, and advance toward a carbon–neutral world. Ensuring food security and sustaining agricultural productivity to meet rapid population growth requires cultivating healthy, nutritious crops. However, the indiscriminate and excessive use of synthetic chemical pesticides has not only targeted pests but also disrupted the environment, compromising food quality, polluting ecosystems, and endangering beneficial insects within agroecosystems. To address these challenges, environmentally friendly pest management strategies have been integrated into the integrated pest management (IPM) framework, aiming to reduce farming communities’ reliance on chemical pesticides. Biological control methods, including predators, parasitoids, and microbial biopesticides (entomopathogens), play essential roles in these greener approaches. Botanical pesticides derived from plants, such as neem, pongamia, and citrus oils, are gaining attention as environmentally safe, non-toxic alternatives. Recent innovations also include genome-editing techniques, such as CRISPR-Cas9 and RNA interference (RNAi), which enhance crop and pest resilience, offering high specificity and ease of application. Additionally, nano-pesticide formulations allow controlled chemical release, optimizing pesticide usage through precise dosages administered at targeted intervals. In response to climate change, several climate-resilient pest management technologies have emerged, including remote sensing, information and communication technology (ICT)-based methods, and precision farming practices. These methods leverage sensors, mobile applications, and unmanned aerial vehicles (UAVs) for efficient pest monitoring and pesticide application. Collectively, these advancements emphasize reduced reliance on synthetic chemicals, promoting greener, residue-free pest control and supporting the cultivation of healthy, sustainable crops. This review comprehensively discusses these trends, focusing on sustainable, eco-friendly pest management approaches.

Managing pests in greenhouses and other sheltered crops requires understanding the origin of colonizing individuals. Nearby vegetation can serve as a source not only for pest insects but also for their natural enemies, making it a key factor in developing conservation biological control strategies. We conducted a study on protected strawberry crops across 50 French farms, examining the presence of major pests and their natural enemies in both greenhouses and crop border vegetation. We first identified pest and beneficial insects in greenhouses and then determined whether these insects were present in crop border vegetation. Our results showed that while crop borders primarily harboured generalist aphid species, aphids specialized in strawberry were nearly absent. Few phytophagous bugs were observed in either sampling sites. In contrast, natural enemies, such as aphid parasitoids and generalist predators, were found in both greenhouses and borders. We further analysed how factors such as seasonality, production region, surrounding vegetation characteristics influenced the presence of pest and beneficial insects in crop borders. The presence of Rosaceae plants (strawberry’s botanical family) had no effect on insect populations. Higher botanical diversity and vegetation cover in borders were associated with increased populations of generalist pests and some biological control agents. These findings highlight the crucial role of crop borders in providing resources and refuges for generalist pest and beneficial insects while having limited impact on specialized pest populations. Targeted border management could either prevent pest colonization of crops or enhance natural enemy populations, contributing to improved pest regulation in greenhouses.

Tree-killing bark beetles are important pests severely affecting forests worldwide. An understanding of their spatio-temporal swarming intensity, typically assessed with pheromone traps, is crucial to guide management actions. While multiple factors have been shown to affect trap catches, we lack knowledge of the effects of inherent dispenser-dependent variations in pheromone release and of local trap position. In a laboratory experiment, we assessed the influence of filling level and temperature on the release rate (Rr) of three commonly used pheromone dispenser products for bark beetles (Pheroprax®, Chalcoprax®, Curviwit®). By conducting a complementary field study at two sites in Germany, we quantified the effect of varying Rr of Pheroprax® and trap position on the number of Ips typographus trapped. Rr of all three products correlated with temperature and strongly declined during the application period in Pheroprax® and Chalcoprax®. In the field, both the temporal variability in filling level and the ambient temperature similarly affected Rr, which in combination led to a fivefold change in trap catches. Additionally, catches varied by a similar magnitude due to local trap position, partly explained by the distance from the forest edge. The large uncertainties found in pheromone trap catches, which may also apply to other pest species, highlight the need for careful interpretation (or correction) of trap data. As a potential improvement of monitoring, we propose swarming models to facilitate more accurate predictions of infestation risk by (i) incorporating uncertainties arising from trap-related factors and (ii) providing continuous information on the spatio-temporal abundance of pest species.