Journal of Pest Science最新文献

Potato crops are kept virus-free by controlling aphid vectors through control schemes that require multiple treatments with insecticides. The aphid Myzus persicae has developed different mechanisms of resistance to insecticides, and there is a growing need of sources for new, more efficient insecticides. Synandrospadix vermitoxicus (Griseb.) Engl.—an Araceae family native to the northwestern region of Argentina, Paraguay, and Bolivia—has been locally described as having insecticidal properties against insect larvae and could be a potential source of new natural insecticides against aphids. We tested the antifeedant and aphicidal effects of two extracts from the tubers of S. vermitoxicus, ethanolic and hexanic, on M. persicae. We treated potato leaves with the extracts to assess their antifeedant effect by measuring host preference changes in M. persicae. Then, we evaluated its aphicidal effect by offering the extracts to aphids through artificial diets, and we tested the aphid probing behavior by electrical penetration graph. We also analyzed the extracts for the main classes of secondary metabolites. We found that both extracts have antifeedant effects, with the hexanic being the strongest, and aphid probing behavior was accordingly affected on leaves treated with hexanic extract. While the ethanolic extract affected the survival of aphids fed on artificial diets, the hexanic extract did not. The analysis of S. vermitoxicus extracts shows an array of flavonoids and triterpenoids compounds. Our results show that the tubers of this plant could be a source for a novel product with potential use on the control of M. persicae on potato crops.

Termites, particularly those of the genus Heterotermes, are significant pests impacting urban and agricultural environments worldwide. Despite their impact, the distribution of Heterotermes has been largely overlooked. Our study aims to predict the potential distribution of 15 Heterotermes species by integrating bioclimatic, land-use, connectivity, soil and elevation variables into species distribution models (SDMs). These models project habitat suitability under three Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP5-8.5) for short-term (2021–2040), mid-term (2041–2060) and long-term (2061–2080) scenarios. Our results underscore the critical influence of temperature, connectivity and soil moisture on termite distribution, revealing potential expansions into new regions due to climate change. Most parts of the Neotropics and Australia could become suitable for at least one species. Our study also examines the efficacy of incorporating phylogenetic data into SDMs, demonstrating its enhanced reliability for predicting distributions of co-occurring species, though its effectiveness diminishes for geographically isolated ones. Future projections indicate significant range shifts due to increased urbanization, agriculture expansion and climate change. Neotropical species are likely to face habitat reductions, especially in South American forests, while several Australian and major structural pest species may expand their range. Currently, densely populated cities in the Neotropics, the south-western US, Australia and South Asia could be within the range of one to five Heterotermes species. In agricultural areas, Australia and the Neotropics—both heavily reliant on agriculture—are highly vulnerable, and this vulnerability is expected to worsen as more land is converted to agricultural use.

The potential arrival of Halyomorpha halys in New Zealand jeopardizes a vast range of crops. Therefore, different preparedness strategies are being assessed before its arrival. A symbiont-targeted control strategy might be used along with other control tactics such as biological control. Prior its implementation, it is necessary to assess its potential impact on non-target stink bug species and their associated egg parasitoids. In this study, the effect of symbiont-targeted control was evaluated on three stink bug species in New Zealand, Oechalia schellenbergii (a native predatory species), Nezara viridula (a cosmopolitan pest) and Monteithiella humeralis (a non-pest adventive species). The interference of anti-symbiont treatment of egg masses with their associated Trissolcus egg parasitoids, namely T. basalis and T. oenone, was also tested. A variable response to symbiont elimination was observed in stink bug species, with N. viridula and M. humeralis undergoing high mortality and no negative effect detected for O. schellenbergii. Parasitism of N. viridula by T. basalis declined on egg masses treated with an anti-symbiont biocomplex or water. Similar results were obtained for T. oenone parasitizing eggs of M. humeralis; while, a parasitism increase was observed for O. schellenbergii egg masses exposed to anti-symbiont treatment and treated with water. These results confirm previous evidence of species-specific response to anti-symbiont control and indicate a moderate and variable effect on egg parasitism. Such responses suggest that symbiont-targeted control would not significantly interfere with the native insect communities that may interact with H. halys, encouraging the future incorporation of symbiont-targeted control in pest management programs.

The delimitation of outbreaks is an essential step in the containment and eradication of non-native plant pests. Outbreaks are habitually delimited by sampling around the initial finding, moving away from this locus in several directions as long as infestations are found (outward strategy). An alternative, inward, strategy would entail starting delimitation with an initial estimate of the location of the frontier and then sampling inward until the first infestations are found or outward until no more infestations are found. We used individual-based modelling to compare the effectiveness and sampling effort of the two strategies. Both successfully contained > 99% of infested plants within the delimited zone. Yet, both had a low probability (< 15%) of containing all the infested plants within the delimited zone. The number of samples of the inward strategy depended greatly on the size of the initially hypothesized infested zone. Best performance of this strategy was obtained with an accurate initial estimate of the infested zone width, while sample size increased strongly when the estimated frontier was far beyond the true location of the frontier. Consequently, the outward strategy uses fewer samples on average than the inward strategy when the position of the frontier is uncertain. Both strategies were prone to error when delimiting outbreaks caused by pests with fat-tailed dispersal. Whether the inward or outward strategy is more effective depends on the certainty about the true position of the leading frontier of the outbreak. Possibilities are discussed for maximizing the cost-effectiveness of sampling for outbreak delimitation.

Aedes albopictus transmits the virus through repeated blood feeding behavior and can also vertically transmit the virus to its offspring. In this study, we analyzed the expression of the TOR gene in Ae. albopictus and found that it was highest in female mosquitoes 24 h after feeding, particularly in the head and thorax. Then, we used to feed method to silence the TOR gene of female mosquitoes and make them suck blood. Silencing TOR resulted in downregulation of amino acid transporter genes SLC7A5 and SLC3A2, as well as regulatory intermediates Rheb and Frizzled-2 in other signaling pathways. In terms of midgut blood digestion, silencing TOR led to reduced glucose metabolism while affecting trypsin (TRY) and chymotrypsin (CHY) enzymes involved in midgut blood digestion, thereby delaying the process. Regarding reproduction, silencing TOR resulted in decreased expression levels of Vitellogenin 2 (Vg2) and Vg3 gene, leading to reduced Vg content in the ovary. Additionally, downstream protein synthesis-related genes 4E-binding protein (4E-BP) and S6 kinase (S6K) within the TOR pathway were affected. Although there were no significant changes observed in egg number or diameter, ovarian development cycle delay occurred along with signs of desiccation and shrinkage in some eggs. Moreover, both egg weight and hatching rate showed a significant decrease. The experimental results suggest that TOR regulates the blood digestion and reproduction process of A. albopictus by influencing post-vampire protease activity and protein synthesis, such as Vg. This provides a theoretical foundation for developing cost-effective and large-scale prevention and control measures for A. albopictus.

Excessive chemical pesticide use has had harmful implications for the environment, animals and humans. Insect resistance has substantially resulted in reduced pesticide efficiency. Global experts are striving to diminish the use of harmful pesticides for pest and pathogen control by adopting eco-friendly methods. Nanotechnology, a recent breakthrough, holds significant promise in addressing these challenges and providing safer environmental alternatives. Nanotechnology applications in sustainable agriculture have tremendous potential in insect pest management with controlled and targeted release mechanisms as smaller sizes of the nanoparticles ensure the proper spread on the pest surface, which results in better action. Biological synthesis of these nanoparticles from plant parts and microorganisms is a valuable alternative to chemical approaches. Nanotechnology is used in formulating nano-based pesticides such as nanosuspensions, nanocapsules and nanoclays. In addition, some nanoparticles are used as pesticides alone. This review covers the significance of bio-nano-insecticides, their synthesis, and formulations as modern pesticides. Additionally, it highlights the previously less-explored impact of nanoparticles on mosquito larvae. The study also encompasses nanopesticide formulation, delivery, mode of action, and effects on non-target species. Furthermore, difficulties and limitations must be resolved and investigated in order to evaluate the laboratory results of nanoparticle application for commercialization. This review also discusses the challenges and limitations hindering the commercialization of nanoparticle applications in insect control. Addressing these challenges is essential to ensure the successful translation of laboratory results into practical and effective pest management solutions.

The pollen beetle Brassicogethes viridescens has become an invasive pest to rapeseed crops in North America, especially Canada, the world’s most prolific grower of rapeseed. The use of conventional insecticides to control Brassicogethes spp. can lead to substantial insecticide resistance development in target pest populations and detrimental effects on non-target organisms in and around rapeseed crops. Therefore, economically and ecologically sustainable alternatives to conventional insecticides must be explored. Given the continued increases in production efficacy- and the nucleotide sequence-specific mode of action of dsRNA pesticide products, RNA pesticides represent a potential tool for use within the management of B. viridescens. We examined the insecticidal efficacy of dsRNA against B. viridescens, using transcripts of its intragenus relative Brassicogethes aeneus as a template for dsRNA design. In B. viridescens, we observed similar sensitivities to dsRNA compared to B. aeneus. Furthermore, survival assays using three model non-target species suggest highly selective insecticidal activity of the dsRNAs. Finally, we generated the first transcriptome draft for B. viridescens, which provides valuable information for future management needs against this pest species. Given these first insights towards sustainable RNAi-based management of B. viridescens, further work (different exposure methods, semi-field larval studies) is needed to develop RNAi-based approaches to managing B. viridescens in both European and North American rapeseed systems.

Pear psyllid (Cacopsylla pyri) is the dominant pest of UK pear orchards, with an estimated cost of £5 million per annum. Insecticide withdrawal and increased pesticide resistance of C. pyri have led many growers to depend more on natural enemies for pest management, including earwigs. However, there is concern how phenological events may shift with future climate change, which may result in phenological mismatches. This study aimed to determine shifts in timing of phenological events within an agroecosystem and predict phenological mismatches or synchronies between trophic levels. We evaluated three models: the C. pyri phenology model, the earwig degree day model and the PhenoFlex model (flowering time). Phenological events predicted by models included: first, full and last flowering time for Pyrus communis; peak psyllid abundance date for first-generation (G1) C. pyri nymphs and second-generation (G2) eggs, nymphs and adults; and peak abundance date for stage 4 Forficula auricularia and adults. Findings indicated that the timing of phenological events was advancing for all trophic levels, becoming significantly earlier under the current time period. Furthermore, predictions indicated that timing events would continue to advance under the RCP8.5 scenario. However, not all phenological events advanced at the same rate; the date of peak C. pyri G1 nymph abundance advanced at a higher rate than full flowering time, which could result in a phenological mismatch by 2071. Conversely, C. pyri and F. auricularia showed phenological synchrony, with peak abundance dates advancing at a similar rate, which could be beneficial for future biological control.

Invasive ant species like Linepithema humile cause significant ecological and economic harm, making effective control strategies essential. Insecticide baits are currently the most effective approach for controlling ants. Therefore, quantifying how palatable or unpalatable baits, bait additives, or toxicants are, is critical for developing effective control methods. Recent research shows that when animals can compare a test food containing a bitterant with another option, they are much better at detecting the bitterant and thus rejecting the test food. Here, we deploy a newly developed comparative evaluation methodology to examine the palatability to L. humile workers of three toxicants commonly used in invasive ant control: fipronil, spinosad, and imidacloprid. Additionally, we tested egg-white protein in sucrose solutions to assess its impact on bait acceptance. Ants showed no significant preference between pure sucrose and sucrose-toxicant solutions, indicating that they either cannot detect the toxicants or do not find them distasteful. Survival tests confirmed that the toxicant concentrations used, fipronil at 0.0001% and 0.001%, spinosad at 0.015% and 0.15%, and imidacloprid at 0.005%, were lethal, with a survival rate of 50% or below after 72 h. However, ants found egg protein additive unpalatable, significantly preferring pure sucrose to a sucrose egg-white protein mix. These findings confirm that three major toxicants are suitable for use in baits, and that reported abandonment or avoidance of toxic baits is not due to the unpalatability of these toxicants. However, the addition of egg protein alone to sucrose baits, even at ratios which optimise colony growth, is likely counterproductive. Future research should investigate the relative preference of invasive ants for various bait matrixes over naturally available food, ensuring more effective pest management strategies.

Carpophilus truncatus (Murray), a nitidulid beetle, has become a major threat to almond industries globally. While there are existing mass trapping strategies for other Carpophilus species, an effective lure for this nut-attacking pest is urgently required. This study leverages our knowledge of the chemical ecology of Carpophilus, particularly its relationship with gut-associated yeasts, to develop a new semiochemical attractant for C. truncatus. Wickerhamomyces rabaulensis was identified as the predominant gut-associated yeast in field-collected C. truncatus. Field bioassays demonstrated that traps baited with live cultures of W. rabaulensis captured more beetles compared to those baited with Hanseniaspora guilliermondii, a yeast from stone fruit-attacking Carpophilus species. GC–MS analysis revealed both qualitative and quantitative differences in the odour profiles of the two yeasts. Seven volatile compounds were identified from headspace of W. rabaulensis and confirmed to be detected by C. truncatus antennae using GC-EAD. Choice-test bioassays showed adult C. truncatus preferred a synthetic blend based on W. rabaulensis volatiles over a commercial lure designed for stone fruit Carpophilus species. Field trials with various formulations of W. rabaulensis volatiles indicated that a modified commercial lure containing isoamyl acetate and isobutyl acetate was more attractive to C. truncatus and caught fewer non-target species such as C. hemipterus. This study demonstrates the potential of insect-yeast chemical ecology in developing effective semiochemical-based lures for monitoring and mass trapping C. truncatus in almond orchards.