Damage caused by Brassicogethes aeneus primarily affects the reproductive organs of rapeseed, disrupting fertilization and often leading to premature pod opening. In addition to direct yield loss, it is hypothesized that injury to generative tissues may also alter seed nutrient composition, particularly the unsaturated fatty acid profile, which is a key determinant of rapeseed quality. To assess this indirect effect, field experiments were conducted in 2024–2025, and seed samples were collected after ripening. The study aimed to evaluate pest-induced variation in nutrient content under different insecticide treatments. Alongside an untreated control, two active substances were tested: a systemic insecticide (acetamiprid) and a combined formulation of acetamiprid and lambda-cyhalothrin. Our results demonstrated that the widely used active insecticides are not effective against B. aeneus adults. Checking the fatty acid (FA) profile, within saturated FAs, the proportion of palmitic acid (C16:0) was the highest in the control; the single and combined pesticide treatments were characterized by increasing LA (C18:2n6) and ALA (C18:3n3) levels, in which both FAs exhibited a linear pattern with the single and combined treatments. In MUFAs, the most important finding was the negligible level of erucic acid (C22:1n9) below the detection limit. Oleic acid (C18:1n9) proportion was generally high (~50) and significantly decreased in treated groups. Oil quality affection highlights the importance of effective pest management to maintain the nutritional and technological value of rapeseed, as shifts in the n6:n3 ratio and thrombogenic index reflect stress responses rather than agronomic benefits.

Coumarin-1,2,4-Triazole hybrids as potential agents against Brassicogethes aeneus (Fabricius 1775).

The growing global population and increasing food demand highlight the need for sustainable agricultural practices that balance productivity with environmental protection. Traditional blanket pesticide spraying leads to overuse of chemicals, environmental pollution, and biodiversity loss. This study aims to develop an innovative approach to precision pest management using mobile computing, computer vision, and deep learning techniques. A mobile measurement platform equipped with cameras and an onboard computer was designed to collect real-time field data and detect pest infestations. The system uses an advanced object detection algorithm based on the YOLOv4 architecture, trained on a custom dataset of rapeseed pest images. Modifications were made to enhance detection accuracy, especially for small objects. Field tests demonstrated the system’s ability to identify and count pests, such as the pollen beetle (Brassicogethes aeneus), in rapeseed crops. The collected data, combined with GPS information, generated pest density maps, which can guide site-specific pesticide applications. The results show that the proposed method achieved a mean average precision (mAP) of 83.7% on the test dataset. Field measurements conducted during the traversal of rapeseed fields enabled the creation of density maps illustrating the distribution of pollen beetles. Based on these maps, the potential for pesticide savings was demonstrated, and the migration dynamics of pollen beetle were discussed.

The use of double-stranded RNA (dsRNA) for pest insect management presents a promising strategy for protecting crop yields, preserving ecosystem integrity and improving food security and safety. However, to address the natural instability of dsRNA, nanocarriers have been developed to enhance both its stability and cellular uptake in vivo. This study evaluates the laboratory efficacy of naked vs complexed dsRNA in the RNAi-mediated control of the pollen beetle Brassicogethes aeneus, a major insect pest of rapeseed crops. After selecting a synthetic cationic polymer that successfully protects dsRNA from degradation by B. aeneus gut nucleases, pollen beetles were orally exposed to either complexed or naked dsRNA targeting essential genes. Our results demonstrate that the low-molar-mass synthetic polymer nanocarrier PAEMA enhances the stability of dsRNA in the insect gut environment and facilitates its release. However, it does not lead to an increased mortality rate of B. aeneus. These findings suggest that nanocarrier systems achieving successful dsRNA complexation and enhanced stability do not necessarily result in a significant reduction of survival in pollen beetles. They also highlight the need for a deeper understanding of the complexation and release conditions specific to each dsRNA-nanocarrier system within a relevant biological context to develop effective dsRNA delivery strategies for B. aeneus control. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Xenostrongylus variegatus (Nitidulidae: Nitidulinae) and Brassicogethes aeneus (Nitidulidae: Meligethinae) are two significant rapeseed pests in China. The former primarily feeds on leaves, while the latter exclusively targets flowers. Insect mouthparts are essential for feeding, with sensilla playing a critical role in food detection. This study compares the mouthpart sensilla of these two pests using scanning electron microscopy for the first time. Results revealed seven types (23 subtypes) of sensilla in male X. variegatus, seven types (21 subtypes) in female, and seven types (18 subtypes) in both male and female B. aeneus. Differences in the types, quantities, and distributions of sensilla were noted, with preliminary inferences made regarding their functions. These findings provide a foundation for further research into feeding behaviors, sensory systems, and integrated pest management strategies for rapeseed pests.

RNAi-mediated knockdown of juvenile hormone acid methyltransferase depresses reproductive performance in female Aethina tumida.

Oilseed rape (OSR, Brassica napus) is a major crop requiring numerous phytosanitary treatments. It is of paramount importance to find sustainable insect pest management to guarantee long term OSR availability. Therefore, we aimed to evaluate the effect of OSR intercropping with faba beans (FB, Vicia faba) on the OSR insect pest complex. In addition, we aimed to understand the underlying mechanisms of crop protection via intercropping by distinguishing between the effects of visual and physical disruptions caused by companion plants and those of olfactory disruptions in host location and selection, and to evaluate whether this effect is direct or indirect. In a field trial run over 2 years, OSR was grown either as a monocrop or intercropped with winter FB (WFB, frost-resistant), spring FB (SFB, frost-sensitive), or polyethylene artificial plants (ART) designed to mimic FB. Compared to the monocropped OSR the OSR + FB intercropping systems significantly reduced the feeding damage caused by cabbage flea beetles (Phyllotreta spp.), the immigration of adult cabbage stem flea beetles (Psylliodes chrysocephala), the number of rape stem weevil (Ceutorhynchus napi) oviposition punctures on stems and the number of pollen beetle (Brassicogethes aeneus) per inflorescence. The intercropping with SFB had a stronger impact on C. napi and B. aeneus than intercropping with WFB. Compared to the monocropped OSR the ART treatment significantly reduced Phyllotreta spp. damage on leaves, C. napi oviposition punctures and the number of B. aeneus. The yield of OSR intercropped with SFB was higher than monocropped OSR, while the other treatments did not affect yield. This study shows that intercropping reduces the incidence of the OSR insect pest complex. Mechanisms of action include the direct visual and physical disruption provided by the companion plants. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The aim of the experiment was to compare the efficacy of the synthetic pyrethroids lambda-cyhalothrin, alpha-cypermethrin and tau-fluvalinate on the spruce bark beetle (Ips typographus L.), as well as to observe the response based on the sex of the spruce bark beetle. The beetles were captured using barrier pheromone traps (Ridex s. r. o.). For laboratory evaluation of sensitivity, the methodology for testing resistance of the pollen beetle Brassicogethes aeneus (Fabricius, 1775) to insecticides was used according to the recommendations of the Insecticide Resistance Action Committee. The sex of each individual was determined by dissection. After 24 hours of exposure to lambda-cyhalothrin, 0% of both males and females survived, with alpha-cypermethrin, 0% of males and 0.16% of females survived, and with tau-fluvalinate, 2.8% of males and 3.87% of females survived. Statistical analysis of the data (using the Kruskal-Wallis test) indicated that tau-fluvalinate is less effective than lambda-cyhalothrin and alpha-cypermethrin, and that the sensitivity of the spruce bark beetle does not depend on its sex. More females (on average 72%) than males (on average 28%) were attracted to the pheromone traps used.

As a result of field studies conducted from 2022 to 2024, measures will be proposed to identify pests of rapeseed crops and protect rapeseed crops. The research was carried out at the Berik farm in the T. Ryskulov district of the Zhambyl region. Field experiments on the use of chemical substances and mineral fertilizers against rapeseed pests were conducted in the studied area. Among the soil-dwelling pests, rapeseed crops were affected by chewing worms and wireworms. The identified entomophages included ground beetles, road beetles, soldier beetles, and ladybugs. Ground beetles, soldier beetles, and ladybugs appeared during the budding stage. The following insecticides were tested against crucifer flea beetles: Sumi-Alpha 5% EC (esfenvalerate, 0.3 L/ha), BI-58 EC (dimethoate, 0.8 L/ha), and Achilles EC (lambda-cyhalothrin, 0.2 L/ha). All tested insecticides demonstrated high biological effectiveness. The biological characteristics of key pests and the factors reducing their population were studied. The following types of pests have been registered in rapeseed crops in the Zhambyl region: Psylliodes chrysocephala L., Eurydema omata L., Eurydema oleracea L., Colahellus sophiae Schall., Entomoscelis adonidis Pall., Phaedon cochlearial F., Ceutorchynchus assimilis Pauk., Baris chlorizans userm., Meligethes aeneus F., Perrisia brassiae Winn., Evergestis extimalis Scop.

Identifying insect predators using camera traps reveal unexpected predator communities in oilseed rape fields

The relationships between weeds and insects in canola stands with different seeding rates are not fully understood. Varying seeding rates in canola crops can create different conditions that affect both weed and insect populations and their interactions. The aim of this work was to determine the response of weeds and insects of selected taxa to different densities of canola stand densities and to clarify the interactions between weeds and insects in canola stands. The field experiment was conducted on a plot located in the cadastral area of the municipality of Pěnčín (Moravia, Czech Republic). The results show that a reduced canola sowing rate of oilseed rape leads to increased weed infestation, which is dominated by one taxon (Papaver rhoeas L.). The increase in weed infestation of canola stands is not reflected in an increase in the diversity of captured insects. Increased canola seeding rate improves weed suppression but increases the number of canola pest insects. A higher number of plants and more canola biomass increase the food supply and, thus, make the stand more attractive to canola pests. The taxon Brassicogethes aeneus dominated the pests species spectrum. Changing the seeding rate of canola results in a response in weed and insect populations. The standard recommended seeding rate is optimal in terms of competitive suppression of weeds and the occurrence of pests and trapped insects. Increasing or decreasing the seeding rate of rapeseed does not bring any benefits in terms of pest regulation or biodiversity. However, the results obtained indicate an interesting weed–insect interaction in the conditions of canola stands.

Global biodiversity has suffered a decline primarily attributed to landscape simplification and intensified agricultural practices. Agricultural environments, characterized by homogeneity and frequent disturbances, are often suboptimal habitats for various insect species. While agricultural fields do favour pests, they generally fail to provide suitable habitats for natural enemies. The inclusion of diverse supporting habitats, such as semi-natural habitats, grassy and woody field margins etc. surrounding agricultural fields, play a crucial role in fostering effective biodiversity conservation. Moreover, determining the influence of different adjacent habitat types is essential in elucidating their influence on pest abundance and parasitism rates. Our two-year field study focused on assessing the abundance of Brassicogethes aeneus and its parasitism rate. The findings revealed that the adjacent habitat type did not significantly increase pest abundance and the parasitism rate of B. aeneus larvae consistently stayed over the threshold for effective biological control throughout the fields. This was attributed to the high proportion (35 and 38% in the 2 study years) of semi-natural habitats within most of the 1 km radius study areas. While our study did not identify any specific adjacent habitat type or habitat within a 1 km radius that directly impacted B. aeneus abundance, it emphasises the intricate interplay between the pests, parasitism and the surrounding environment because the interactive effect of distance from the crop edge and habitat type had a significant influence on B. aeneus infestation levels but not on parasitism. Decision tree analysis suggests that > 18% semi-natural habitat is needed to ensure sufficient levels of parasitism for effective biological control. A comprehensive understanding of habitats that influence not only B. aeneus but also other pests is critical for the successful implementation of IPM strategies and conservation initiatives within the agricultural sector.

The pollen beetle, Brassicogethes aeneus, is an economically important pest of oilseed rape (Brassica napus) throughout Europe. The control of B. aeneus has relied heavily on the use of chemical insecticides leading to the evolution of resistance. However, investigation of the molecular basis of resistance has been hampered by an absence of genomic resources for this species, including the lack of a reference genome assembly. Here we address this need by generating a chromosome-scale genome assembly for B. aeneus. A combination of long-read single-molecule sequencing and in vivo chromatin conformation capture (Hi-C) sequencing was used to generate an assembly of 585 Mb, comprising 11 chromosome sized scaffolds (scaffold N50 of 61.6 Mb) and containing 13,381 protein-coding genes. We leveraged the new assembly, in combination with post-genomic functional approaches to investigate the molecular basis of metabolic resistance to pyrethroid insecticides in B. aeneus. Our data confirmed that two P450s, CYP6BQ23 and CYP6BQ25, have the capacity to metabolise the pyrethroid deltamethrin in B. aeneus and thus have the potential to confer resistance. However, the relative expression of these P450s in pyrethroid susceptible and resistant strains suggests that CYP6BQ23 plays a much more significant role in resistance than CYP6BQ25. In summary, the high-quality genome assembly for B. aeneus reported here provides a valuable resource for future research on this species. Our findings on P450-mediated resistance to insecticides are of applied relevance for the development of strategies for the sustainable control of this important pest.

Understanding the dynamics of pest immigration into an agroecosystem enables effective and timely management strategies. The pollen beetle (Brassicogethes aeneus) is a primary pest of the inflorescence stages of oilseed rape (Brassica napus). This study investigated the spatial and temporal dynamics of pollen beetle immigration into oilseed rape fields in Denmark and the UK using multiple methods, including optical sensors. In all fields, pollen beetles were found to be aggregated and beetle density was related to plant growth stage, with more beetles occurring on plants after the budding stage than before inflorescence development. Optical sensors were the most efficient monitoring method, recording pollen beetles 2 and 4 days ahead of water traps and counts from plant scouting, respectively. Optical sensors are a promising tool for early warning of insect pest immigration. The aggregation pattern of pollen beetles post immigration could be used to precisely target control in oilseed rape crops. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Oilseed rape is frequently damaged by insect pests. Much attention is paid to the protection of oilseed rape against Brassicogethes aeneus (Coleoptera: Nitidulidae), which is one of the most significant pests of spring and winter oilseed rape. The presence of different pollen beetle species was monitored in the Czech Republic in the years 2011–2013. A minimum of 500 individuals were captured at each site. Morphometric characteristics and the morphology of male and/or female genitalia were used to determine species. B. aeneus, B. subaeneus, B. viridescens and B. coracinus were most abundant. Other species presented in oilseed rape were B. coeruleovirens, B. czwalinai, B. matronalis, B. anthracinus, Boragogethes symphyti, Cychramus luteus, Fabogethes nigrescens, Genistogethes carinulatus, Meligethes atratus, Sagitogethes maurus, and Lamiogethes atramentarius. Our main conclusion is that the reason for the presence of the pollen beetle species associated with their development into non-cruciferous plants in oilseeds is the sufficiency of pollen as food for beetles. In addition, they may occur here incidentally, as they can be transported relatively long distances by air. Accompanying species of pollen beetles probably also have a positive effect on abundance reduction in species considered to be harmful as they are hosts to parasitoids of the oilseed rape pest.

The protection of European oilseed rape (OSR) from damaging insects relies on pyrethroid insecticides, but the development of resistance in key coleopteran pests such as the pollen beetle (Brassicogethes aeneus) and the cabbage stem flea beetle (Psylliodes chrysocephala) has resulted in reduced effectiveness of these insecticides. The sodium channel gene mutation L1014F knock-down resistance (kdr) is a contributing factor in resistance to pyrethroids in B. aeneus and P. chrysocephala, but little is known about the status of resistance in weevils of the genus Ceutorhynchus (Coleoptera: Curculonidae). Therefore, the present study investigated pyrethroid susceptibility and the presence of the kdr mutation in four Ceutorhynchus species. The kdr mutation in either its heterozygous or homozygous form was found in all investigated Ceutorhynchus species (C. picitarsis, C. pallidactylus, C. napi and C. obstrictus). Samples where pyrethroids in bioassays still provided control at 100% field rate or below contained kdr at frequencies of ≤12.5%, whilst bioassays using 100% field rate that did not control Ceutorhynchus populations contained homozygous resistant individuals at frequencies of greater than 55%. Field sampling demonstrated that kdr frequencies in populations of C. picitarsis and C. obstrictus collected from across France and Germany ranged from 0 to 100%. The present study demonstrated the potential of all four Ceutorhynchus species tested to develop pyrethroid resistance via the L1014F (kdr) mutation. Although kdr frequency varies among species and geographic locations, the risk of loss of pyrethroid insecticide effectiveness is high. Integration of other control tools for resistance management is therefore needed. © 2023 Society of Chemical Industry.

The pollen beetle (Brassicogethes aeneus) causes significant yield loss in oilseed rape (Brassica napus). Predicting population changes remains a scientific challenge, especially since its phenology and abundance varies dramatically over space and time. We used generalized additive models to investigate the long-term trends in pollen beetle annual, seasonal and monthly counts from Rothamsted 12.2 m suction-traps. We hypothesised that the beetle's abundance is positively related to the area of oilseed rape at a national and regional level. We used random forest models to investigate the inter-generational relationship within years. Although Brassicogethes aeneus annual counts and area of oilseed rape grown in the UK both increased by 162% and 113%, respectively, over the time period studied, they were not significantly related. The size of the immigrating pollen beetle population (up to 1 June) can be explained both by the size of the population in the previous summer and prevailing winter temperatures, indicating a positive feedback mechanism. Currently, pollen beetle numbers continue to increase in the UK, meaning that control issues may persist. However the relationship between counts in spring, during the susceptible phase of the crop, and counts in the previous summer indicates that it may be possible to forecast the counts of the spring migration of Brassicogethes aeneus a few months in advance using suction-trap samples, which could aid decisions on control options. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Simple SummaryInsect pest management in oilseed rape (OSR) is challenging for farmers due to the lack of effective insecticides, so conservation biocontrol—reliance on natural pest control and management methods to support populations of the natural enemies of crop pests—is part of the solution for a greener future. Sown wildflower field margins are known to benefit many natural enemies of crop pests. However, the most effective natural enemies of OSR pests are parasitoids, which specialise in attacking these pests, which in turn specialise on Brassica host plants (including OSR), but few field margin mixtures contain brassicas. We screened six different species in the field to find the plants with the best potential as ‘banker plants’ to support parasitoid populations whilst not exacerbating the pests. Forage rape was the best ‘all-rounder’; supporting good numbers of pollen beetle parasitoids and also supporting parasitoids of weevil and brassica pod midge pests. Careful consideration of the brassica component of field margin mixtures could extend functionality towards enhanced biocontrol of specialist pests.European agri-environment schemes include the use of flower-rich field margins to promote on-farm biodiversity, but species mixtures rarely include Brassicaceae. As pests of oilseed rape (OSR; Brassica napus) and their parasitoids are mostly brassica specialists, including brassica ‘banker plants’ in the mixtures would help support these important biocontrol agents and improve pest control throughout the crop rotation. We assessed the potential of six brassicaceous plants (replicated plots grown in the field) to enhance populations of parasitoids of OSR pests whilst minimising proliferation of their pest hosts. Fodder radish (Raphanus sativus) facilitated high production of parasitoids of the pollen beetle pest (Brassicogethes aeneus) but may proliferate Ceutorhynchus weevil pests due to low parasitism. Turnip rape (B. rapa) and the B. rapa hybrid ‘Tyfon’ showed potential to perform a trap cropping function for pests, but their early flowering phenology resulted in B. aeneus larvae escaping parasitisation, potentially assisting proliferation of this pest. Forage rape B. napus exhibited similarly high B. aeneus parasitoid production characteristics to R. sativus but did not potentiate problems with other pests, indicating that it would be a favourable banker plant option. Careful selection of plants in field margin mixtures is therefore needed to maximise their benefits and ideally the whole crop pest-beneficial complex needs to be studied, as focus on a single major pest risks unintended consequences with other pest problems.

Agricultural landscapes provide resources for arthropod pests as well as their natural enemies. To develop integrated pest management (IPM) practices, it is important to understand how spatiotemporal location influences crop colonization and damage severity. We performed a 3-year (2016-2018) field experiment in winter oilseed rape (OSR, Brassica napus) fields in Estonia, where half of the fields were within 500 m of the location of the previous year's winter OSR field and half were outside this zone. We investigated how distance from the previous year's OSR crop influences the infestation and parasitism rates of two of its most important pests: the pollen beetle (Brassicogethes aeneus) and the cabbage seed weevil (Ceutorhynchus obstrictus). When the distance from the previous year's OSR crop was >500 m, we recorded significantly reduced pest pressure by both B. aeneus and C. obstrictus in the study fields. Biocontrol of both pests, provided by parasitic wasps, was high in each study year and commonly not affected by distance. Mean parasitism rates of B. aeneus were >31%, occasionally reaching >70%; for C. obstrictus, mean parasitism was >46%, reaching up to 79%, thereby providing effective biocontrol for both pest species. Spatiotemporal separation of OSR fields can reduce pest pressure without resulting in reduced parasitism of OSR pests. This supports a spatiotemporal field separation concept as an effective and sustainable technique for IPM in OSR. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

IntroductionAnimal nutritional strategies have been extensively studied in vertebrates, where generalism at the individual scale is the rule. In insect herbivores, the determinants of the nutritional strategy of individual-scale generalists remain poorly studied, and the focus has been placed mainly on the influence of plant defense. Moreover, the integration of a physiological dimension in such studies remains rare. Here, we investigated the determinants of the nutritional strategy of pre-diapausing pollen beetles,Brassicogethes aeneus, with a focus on the influence of macronutrients. Before their diapause, pollen beetles are known to feed from plants belonging to many different families. This raises three questions: (i) Is the generalism of pollen beetles a populational consequence of individuals specialized on different plant families? (ii) Do individuals feed at random on flowers available or do they have a particular nutritional strategy? and (iii) In case of non-random feeding choices, do pollen macronutrients explain this nutritional strategy?MethodsTo answer these questions, we used a series of laboratory experiments including feeding choice tests on flowers and artificial substrates, quantification of pollen nutrient content, quantification of the insect energetic budget, and performance experiments.ResultsWe show that pollen beetles are generalist at the individual scale, and that clear and stable food preferences are established over a few hours in a multi-choice context. Pollen beetles prefer to feed on flowers with a carbohydrate-rich pollen, and this preference is adaptive since performance correlates positively with the plant carbohydrate content. This better performance may be explained by the fact that individuals feeding on carbohydrate-rich resources accumulate more glycogen and total energetic reserves.DiscussionThis study represents one of the few evidences of generalism at the individual scale in an herbivorous insect. It provides a better understanding of the nutritional strategy of a non-bee pollen feeder and shows the importance of carbohydrates in this strategy. It highlights the need to combine assessments of the plant macronutrient content and insect energetic budget in an adaptive framework to better understand the nutritional strategies of herbivores.