Journal of Pest Science最新文献

In Europe, the recently reported plant pathogen Xylella fastidiosa subsp. multiplex affects several wild, ornamental, and cultivated trees causing scorch diseases. In 2018, the sequence type 87 was reported in Tuscany on Mediterranean shrubs and trees. Although spittlebugs (Hemiptera: Aphrophoridae) were already identified as main vectors of this bacterium in Europe, their role in the transmission of this subspecies has not been ascertained yet. In this study the ability of Philaenus spumarius and Neophilaenus campestris to acquire and transmit Xylella fastidiosa subsp. multiplex sequence type 87 from and to Rhamnus alaternus was evaluated in two-year semi-field experiments. To acquire the bacterium, insects were confined on wild, naturally infected R. alaternus shrubs for 120 h. Then, they were transferred to healthy plants and maintained in cages for 96 h. To follow the infection, plant samples were collected every two months for three times. Tested plants were destroyed at the end of experiments and roots, twigs and leaves were analysed. Philaenus spumarius showed a significantly higher survival rate than N. campestris. The infection status of both insects and plants was assessed through molecular analysis. P. spumarius and N. campestris were able to infect healthy plants although the acquisition rate and the estimated probability of transmission appeared to be low. These findings provide new accounts on the role of two polyphagous insect vectors in spreading a quarantine organism, which is lethal to a huge number of plant species. However, further studies are needed to disclose more specific interactions within this complex pathosystem.

Changes in land use is an important driver of insect pest population dynamics, but the long-term effects of land use may be contingent on changes in some factors. To identify potential effects of change in cropping pattern on agricultural pest population trends, data from large temporal and spatial scales are needed but are rarely available. Here, we used long-term (15 years) pest monitoring data across a regional scale and across independent gradients of land-use intensity at the landscape level (61 agro-landscapes with a radius of 2.0 km), to investigate the effects of the expansion of area devoted to major cereal crops on population trends of polyphagous Helicoverpa armigera in northern China. We found that an increased proportion of the land planted to maize and wheat in the landscape had an indirectly positive effect on the activity density of the summer population of H. armigera by increasing the population density of the preceding spring generations. Stable carbon isotope analysis suggested that maize acted as the source habitat for H. armigera population in the growing season. At the regional level, long-term expansion of maize and wheat production, as well as the contraction of cotton area, was associated with an increased density of H. armigera in spring generations across years, although temperature and precipitation factors also had significant effects on pest population sizes. These results across both temporal and spatial scales indicated that, in addition to Bt cotton contraction, increased cereal crops cultivation was an important driver of the H. armigera population increases in recent decades in northern China.

The Yellow-legged hornet (Vespa velutina nigrithorax) was accidentally introduced into south-western of France in 2004 and rapidly spread throughout France and neighbouring countries. This insect predator hunts honey bees leading to a hornet-mediated beekeeping risk (HBR) with potential mortality of honey bee colonies and important economic costs. However, the spatial distribution of HBR is not yet assessed and is urgently required to formulate suitable management plans in Western Europe. We conducted a two-year citizen science survey in France and Germany to assess the spatial distribution of (1) the hornet and (2) HBR, and to (3) determine the environmental factors involved. A total of 1678 beekeepers participated in the survey. As expected, the hornet was established throughout the French territory, and was mainly detected near the French border in Germany. We found that HBR was substantially lower in Germany than in France. Temperature had a positive effect on both hornet presence and HBR, whereas distance to the introduction point had a negative effect in both France and Germany. These results suggest that the impact of V. velutina on beekeeping is not homogenous across the invasion range and could be reduced on the eastern front due to the continental climate. Taking into account the spatial variability of HBR could help to formulate regionally adapted management plans to limit the impact of V. velutina on biodiversity, human health and economic sectors.

Aromia bungii Faldermann (Coleoptera: Cerambycidae) is an emerging invasive pest of economically important Prunus species that is native to China, Mongolia, the Russian Far East, Korea, and Vietnam. It was recently introduced to Japan, Germany, and Italy, where it is spreading and damaging crops and ornamental trees. It exhibits an adaptable lifecycle, a high reproductive output, and the larvae live concealed under the bark of infested trees, which are traits that promote its invasiveness. Detection and monitoring of A. bungii currently rely upon visual identification of infested trees that are usually already damaged, which is inefficient and not target-specific. Current control methods rely primarily upon the labour-intensive physical removal of infested trees. Although native parasitoid natural enemies of A. bungii provide control in Chinese orchards, none are appropriate for classical biological control in invaded areas due to biosafety concerns surrounding their broad host ranges. However, entomopathogenic fungi and nematodes may provide viable options for biological control in invaded ranges. Recent advancements in semiochemical baited traps may provide sustainable, target-specific, and efficacious methods to monitor and control A. bungii. There remains much to learn about the biology and control of A. bungii, and continued advancements in the study of sustainable control tools are needed for the management of this emerging pest.

An aqueous ant bait consisting of sucrose (4.55% w/v), essential amino acids (EAAs, 1%), and water is known to be highly appealing to multiple ant species throughout the foraging season. Here, we tested whether this bait, combined with boric acid as the lethal agent, has potential for control of pest ants. Specifically, we: (1) assessed bait lethality to diverse species of ants (European fire ants, Myrmica rubra, western carpenter ants, Camponotus modoc, thatching ants, Formica oreas); (2) tested the effect of boric acid concentration on mortality of M. rubra workers and colonies; (3) compared consumption, and demise timeline, of lethal liquid baits and lethal gel baits; and (4) investigated whether lethal liquid baits reduce the size of M. rubra colonies. In laboratory experiments, the bait induced rapid worker mortality (< 22 days) in all three species of ants tested. Increasing the concentration of boric acid from 1% to 5.4% accelerated the demise of only worker ants, but not queen ants, in M. rubra colonies, indicating that 1% boric acid is sufficiently lethal. Worker ants of M. rubra strongly preferred liquid baits to gel baits of identical nutrient composition, with the former bait accelerating worker demise. In a field experiment in a public park heavily infested with M. rubra, the 12 treatment colonies provided with a lethal liquid bait (4.55% sucrose; 1% EAAs; 1% boric acid) over 114 days significantly declined, whereas the 12 control colonies provided with the corresponding non-lethal bait did not. The bait, with appropriately adapted bait deployment protocol, should be tested for control of other pest ants, particularly those that preferentially feed on liquid foods.

Whole ecosystem-based approaches are becoming increasingly common in pest management within agricultural systems. These strategies consider all trophic levels and abiotic processes within an ecosystem, including interactions between different factors. This review outlines a whole ecosystem approach to the integrated pest management of pear psyllid (Cacopsylla pyri Linnaeus) within pear (Pyrus communis L.) orchards, focusing on potential disruptions as a result of climate change. Pear psyllid is estimated to cost the UK pear industry £5 million per annum and has a significant economic impact on pear production globally. Pesticide resistance is well documented in psyllids, leading to many growers to rely on biological control using natural enemies during the summer months. In addition, multiple insecticides commonly used in pear psyllid control have been withdrawn from the UK and Europe, emphasising the need for alternative control methods. There is growing concern that climate change could alter trophic interactions and phenological events within agroecosystems. For example, warmer temperatures could lead to earlier pear flowering and pest emergence, as well as faster insect development rates and altered activity levels. If climate change impacts pear psyllid differently to natural enemies, then trophic mismatches could occur, impacting pest populations. This review aims to evaluate current strategies used in C. pyri management, discuss trophic interactions within this agroecosystem and highlight potential changes in the top-down and bottom-up control of C. pyri as a result of climate change. This review provides a recommended approach to pear psyllid management, identifies evidence gaps and outlines areas of future research.

The “ecology of fear”, i.e., physiological and behavioral alterations displayed by pests in response to predation risk, has recently been proposed as a sustainable alternative to chemicals for pest control. However, the development of such a strategy requires a detailed understanding of the signals and cues underlying the pest-antagonist interaction and eliciting the prey behavioral alteration. Here, we characterized the substrate-borne vibrations produced during the interaction between the green peach aphid Myzus persicae and its antagonists, the parasitoid wasp Aphidius colemani and the ladybug Adalia bipunctata. Thereafter, coupling the electrical penetration graph (EPG) with a stimulus controller, we evaluated whether the playback of the vibrations, alone and in combination with the alarm pheromone, impacted aphid probing behavior and interaction with the host plant. Aphids responded to vibrations exhibiting longer non-probing, shorter intracellular probes, i.e. the behavior through which the insect evaluates host plant quality, delay in accessing the phloem vessels and decrease of the frequency of phloem salivation events. In contrast, on plants treated with the alarm pheromone, insects displayed longer intracellular probes. We hypothesize that the alarm pheromone, signaling a distant threat, might induce a careful evaluation of the host plant in order to decide the magnitude of the reaction. On the other hand, vibrations might indicate a closely approaching threat pushing the aphid to rush the host evaluation process and the whole feeding process. The possible repercussion of the behavioral alterations observed on the dynamics of aphid-borne plant virus transmission is also discussed.

This study was designed to investigate the acute toxicity (mortality) and sublethal effects (fertility and potential natality) of carlina oxide, the main constituent of Carlina acaulis essential oil (EO), against adults of Metopolophium dirhodum (Walker) (Hemiptera: Aphididae). Moreover, its toxicity was evaluated against two aphid natural enemies, i.e., Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae) and Chrysoperla carnea Stephens (Neuroptera: Chrysopidae). The highest tested concentration (3.0 mL L⁻¹) resulted in 96.7% mortality of adults of the target pest, highlighting that this concentration of carlina oxide had a similar effectiveness as the positive control we used. Furthermore, probit analysis allowed the estimation of a LC₅₀ of 1.06 mL L⁻¹ and a LC₉₀ of 2.58 mL L⁻¹ for the target pest, which resulted in a much higher mortality rate than that found on natural enemies, i.e., A. aphidimyza (6.7 ± 4.7% ± SD when exposed to the aphid LC₉₀) and C. carnea (7.0 ± 5.5% ± SD when exposed to the aphid LC₉₀), showing the limited non-target impact of carlina oxide. The use of LC₃₀ and LC₅₀ of this compound allowed the fertility inhibition of the target pest by 35.68 ± 6.21% and 23.66 ± 10.58%, respectively, and potential natality inhibition of the target pest by 52.78 ± 4.48% and 59.69 ± 5.60%, respectively. Of note, carlina oxide showed excellent insecticidal activity against M. dirhodum, comparable to the commercial insecticide considered. Overall, the low toxicity of carlina oxide toward A. aphidimyza and C. carnea makes it a safe compound for non-target organisms as well as suitable for developing a green insecticide for the management of M. dirhodum and perhaps other insects of agricultural or medical and veterinary interest.

The European spruce bark beetle Ips typographus is a widespread pest in Norway spruce-dominated forests in Eurasia. Predicting its phenology and voltinism is crucial to plan forest management measures and to mitigate mass outbreaks. Current phenology models are based on constant temperatures inferred from laboratory experiments; however, insect life cycles under natural conditions are rather driven by diurnal and seasonal temperature fluctuations. Therefore, phenology models based on fluctuating temperatures would reflect field conditions more realistically and might thus improve model predictions. In a laboratory experiment, we investigated the development of I. typographus, applying mean temperatures between 3 and 35 °C and diurnal temperature oscillations of up to ± 15 °C. Subsequently, we calibrated developmental rate models and applied them to climate data, in order to assess the effect of temperature fluctuations on voltinism under field conditions. Our results showed that diurnal temperature oscillations significantly affected developmental rates. Compared to constant temperatures, development was faster at temperature oscillations falling below the lower developmental threshold, and slower at temperature oscillations exceeding the developmental optimum. Furthermore, short exposures to suboptimal temperatures affected I. typographus less than expected from constant conditions. Natural temperature fluctuations thus accelerate development under cool, shaded conditions, whilst slowing it under hot, sun-exposed conditions, thereby ultimately affecting voltinism. Our findings highlight the importance to account for diurnal temperature fluctuations for more accurate predictions of developmental rates of I. typographus in natural thermal environments, and provide the fundament for improving current phenology models to support effective bark beetle management in a warming climate.

Lepidopteran borers stand out as the most destructive pests in sugarcane, leading to reductions in stalk weight, juice quality and sugar recovery. Presently, integrated pest management (IPM) systems are utilized for sugarcane borer management, employing diverse methods encompassing cropping system, chemical pesticides, behavioral manipulation, biological agents and the selection of resistant varieties. However, the effectiveness of this strategy remains controversial due to concerns about harmful residues, formulation limitations, environmental variability, labor shortages and increased input costs. Currently, multiple lines of transgenic sugarcane expressing insecticidal genes from the bacterium Bacillus thuringiensis (Bt) have been developed globally, offering the prospect of increases production with reduced pesticides application, thereby eliminating the negative effect of IPM. In Brazil, the first genetically modified sugarcane cultivars resistant to the sugarcane borer have been approved and released for commercial cultivation, shedding a bright light on a viable solution for sugarcane borers. This paper reviews borer species and distribution, the significant damage caused by sugarcane borers, current control approaches and the future effective control strategies. Additionally, this work provides comprehensive understanding on Bt sugarcane, serving as an additional tool to complement conventional sugarcane borers control resistance programs.