Search Results (70)

The cotton seed bug (CSB) (Oxycarenus hyalinipennis), an emerging pest of cotton worldwide, causes significant economic damage through seed feeding and fiber contamination. Effective monitoring tools for this species are currently lacking, limiting the implementation of integrated pest management (IPM) strategies. In this study, we characterized the volatile profile of whole, unprocessed cotton seeds and evaluated the behavioral responses of adult CSBs to individual compounds and synthetic blends. Using gas chromatography-mass spectrometry (GC-MS) analysis, we identified 17 volatile compounds, including aldehydes, hydrocarbons, aromatic compounds, terpenes, ketone, and fatty acid ester. Y-tube olfactometer assays revealed that only four individual compounds, 1-heptanal, 1-decene, 1-nonanal, and isopropyl palmitate, elicited significant attraction from both males and females. Chemical blends of these four compounds formulated in a natural ratio (1:16:4:2) and an equal ratio (1:1:1:1) demonstrated strong, dose-dependent attraction, with optimal responses occurring at low doses (0.01 µg). Robust behavioral attraction was observed in response to the complete four-component blend. Removal of any individual compound significantly reduced attraction in a sex-specific and dose-dependent manner. Notably, removal of the fatty acid ester isopropyl palmitate from the blend almost resulted in a complete loss of attraction. This study provides the first comprehensive characterization of volatile emissions from whole cotton seed and presents the first evidence in CSB that 1-decene and isopropyl palmitate function as key volatile components of the foraging cue for attraction. These findings advance our understanding of CSB chemical ecology and highlight the potential of dose-dependent, multi-component kairomonal blends as tools for monitoring and management of CSB. Full article

Gnathotrichus materiarius Fitch, 1858 is a North American ambrosia beetle that has progressively expanded its distribution across Europe during the twentieth and twenty-first centuries. The aim of this study was to assess its occurrence in Slovakia based on multi-year surveys conducted in the Záhorie region and to document its first national record. Monitoring was carried out in 2021 and 2025 in pine-dominated stands using traps baited with pheromone and kairomone attractants. No individuals were detected in 2021. In 2025, two adults of G. materiarius were captured at a single site during the first inspection of traps baited with a (+)-α-pinene and ethanol blend. A large volume of stored pine timber was present in close proximity to the capture site, providing suitable breeding material. The findings suggest a recent introduction or early stage of establishment in Slovakia. Although the species is regarded as a technical pest of coniferous wood, it does not colonize healthy trees and currently poses a limited risk to vital forest stands. Continued targeted monitoring is important to assess its further spread. Full article

Trypophloeus binodulus is a bark beetle present in mature poplar plantations that damages the bark of healthy trees and is currently expanding, posing a risk to these crops and impacting their economic profitability, since there is currently no early detection method or control strategy for this pest. This study was carried out in the province of León in three experimental plots affected by this pest, located in Villasabariego, Villoria de Órbigo, and Turcia to evaluate the effectiveness of different combinations of primary and secondary kairomonal compounds in different trap types. Moreover, the capture results obtained during 20 and 22 weeks in 2023 and 2024 years, respectively, of the field trial made it possible to determine that the most effective lure for monitoring and controlling T. binodulus is Ethanol + Salicylaldehyde, since its synergistic effect enhances its attractiveness. Also, the results confirmed that ESCOLITRAP^® traps are the most effective under field conditions. These results identify an effective method for monitoring the pest, which could be a promising candidate for adoption by poplar growers, enabling progress toward sustainable management through semiochemical compounds. Full article

The codling moth (Cydia pomonella L.) is a major pest of pome fruits worldwide, guided by semiochemicals to locate hosts and oviposition sites. Quince (Cydonia oblonga Mill.), although less studied, is also affected by this pest. This study aimed to identify behaviorally active compounds for codling moth by characterizing the volatilome of quince cultivars. Volatile profiles were analyzed across four phenological stages (flowering, unripe, growth, and ripe fruit) using solid-phase microextraction and GC–MS. The cultivars evaluated were Champion, INTA 37, INTA 117, and INTA 147. Female oviposition behavior and neonate larval host choice were also assessed. Identified volatiles included esters, sesquiterpenes, monoterpenes, alcohols, aldehydes, and norisoprenoids. Among monoterpenes, limonene, consistently detected across all cultivars and stages, emerged as a key kairomone. Volatile composition varied across phenological stages, with the fruit growth stage exhibiting the highest diversity and abundance of compounds previously reported as behaviorally active. This pattern coincided with peak female oviposition and larval host selection. Females oviposited mainly on leaf surface, whereas during ripening, eggs were deposited on fruit lacking pubescence. Overall, INTA 147 was the most preferred cultivar. These findings highlight quince volatiles, particularly Limonene, as potential candidates for the development of semiochemical-based tools to improve codling moth management. Full article

The flower thrips, Frankliniella intonsa, is a major pest threatening citrus production. However, chemical control remains the primary management measure, which poses significant risks on ecosystems. Hence, it is urgent to prioritize more eco-friendly measures to efficiently control thrips. The ladybird, Cheilomenes sexmaculata, is a predominant natural enemy in the local citrus agroecosystem and could play a key role in suppressing thrips in agricultural landscapes. Although some ladybirds are known to be attracted to herbivore-induced plant volatiles (HIPVs), little is known about the specific attractive compounds and the effect of F. intonsa-infested lemon plants on the predatory response of C. sexmaculata. Here, we studied the chemical interaction between F. intonsa, C. sexmaculata, and lemon plants. In dual-choice behavioral assays, C. sexmaculata adults significantly preferred volatiles from F. intonsa-infested plants over those from healthy plants. Volatile collection and analysis identified six monoterpenes, five of which (α-pinene, β-pinene, sabinene, myrcene, and eucalyptol) individually attracted C. sexmaculata at specific concentrations. Moreover, a blend of these five compounds, formulated at their optimal attractive concentrations, elicited a stronger attraction in C. sexmaculata than individual compounds, indicating a synergistic interaction. This attractive blend can thus be used to develop a kairomone-based lure to enhance biological control and to complement existing integrated pest management approaches against thrips in lemon agroecosystems. Full article

Spodoptera frugiperda is a major agricultural pest both in Brazil and worldwide, with widespread resistance to synthetic insecticides. This study evaluated the toxicity and residual activity of toxic bait formulations combining 17 insecticides with the plant-based kairomone attractant Noctovi^® 43SB against S. frugiperda adults. Bioassays were conducted with 48 h-old, food-deprived adults. Toxicity was assessed by incorporating insecticides at 2% concentration into Noctovi^® 43SB. Residual activity was measured by applying toxic baits on cotton leaves and testing at 3, 7, 15, 21, and 30 days after application (DAA). Insecticides based on methomyl, spinetoram, spinosad, indoxacarb, malathion, and zeta-cypermethrin induced over 95% mortality. Methomyl showed the greatest toxicity (LC₅₀ = 322 mg a.i. L⁻¹; LC₉₀ = 1160 mg a.i. L⁻¹). Eleven insecticides maintained residual activity (≥70%) after 30 DAA, except malathion. Overall, toxic bait formulations combining Noctovi^® 43SB with methomyl, spinosad, spinetoram, or indoxacarb proved highly effective, offering both rapid and prolonged control of S. frugiperda adults. These findings highlight attract-and-kill as a promising tool for sustainable management of this pest. Full article

Recent intensive research on the cypress bark beetle, Phloeosinus aubei was prompted because of its invasion of Central Europe that caused serious damage to scale-leaved conifer ornamental trees. This dynamic also increased the risk of accidental introduction into North America. In contrast to other historically well-studied bark beetles infesting spruce, pine or broad-leaf trees, intense study of the pheromones and host plant kairomones of bark beetles associated with cupressaceous trees has only begun in the past decade. This highly specialized clade is represented by the genus Phloeosinus. The pressing need for semiochemical-baited traps demands the identification of behavior-modifying compounds. This challenge involves unraveling the various stimuli interacting in the complex communication system to reveal the composition of signal bouquets and the absolute configuration of their components capable of evoking behavior responses. In this short overview we describe the recent research results on host-finding and intraspecific chemical communication of P. aubei, with a short outlook on the species of this genus. Full article

Implementing mating disruption (MD) programs to manage codling moth (CM), Cydia pomonella (L.), should be based on knowledge of how effectively each program disrupts female mating. A recent survey of 142 pome fruit orchards under MD in Washington State and Oregon found that, on average, about half of the CM females caught in traps baited with a kairomone-based lure were mated. However, significantly lower proportions of mated females were sampled when the intensity of the MD program was increased. A standardized protocol that could reduce the large inter-orchard variability was developed, involving weekly releases of sterilized CM adults. Eleven trials were conducted in 2023 and 2024 across 82 orchards treated with 20 MD programs. The intensive MD programs were significantly more effective in reducing mating of both wild and sterile CM females. Three advantages of using sterile moths to assess CM MD were identified: (i) it minimized the impact of wild immigrant females or individuals previously exposed to sublethal spray residues; (ii) it allowed greater numbers of females to be dissected, thus increasing the precision of the mean value; and (iii) it and allowed the collection of sufficient sampling data (>5 CM females per site) from 30% more orchards than relying on wild moth catch. Full article

Most assessments of sex pheromone-based mating disruption (MD) for codling moth (CM), Cydia pomonella (L.), have not included measurements of female mating. The recent development of a dual-sex lure (CM4K) combining ethyl (E,Z)-2,4-decadienoate, 4,8-dimethyl-1,3,7-nonatriene, pyranoid linalool oxide, and acetic acid has significantly increased the catch of female CM and made it easier to directly assess various MD programs. Samples of wild female CM populations using this lure were collected from 142 orchards, either untreated or treated with one of seven different dispenser systems for CM MD, from 2021 to 2022. The proportion of unmated females ranged from <0.20 to >0.80 with a median of 0.43 in both years. No differences in the mean proportion of unmated females were found between apple and pear. Moth immigration and supplemental insecticide sprays were hypothesized to be key factors affecting the variability within each MD tactic. Mating levels were significantly higher later in the season. More females were unmated in conventional compared with organic orchards. Means for females not mating among the CM MD programs varied over a 0.20 range, except for one. The exception occurred when two MD tactics (aerosol units plus hand-applied dispensers) were accidentally used together, and the proportion of unmated females was significantly higher. Full article

Stink bugs (Hemiptera: Pentatomidae and Scutelleridae) produce a wide range of semiochemical compounds that function as pheromones, allomones, synomones, and kairomones. This study aimed to isolate, identify, and synthesize the main semiochemical components of the metathoracic glands of Aelia rostrata, A. melanota, Eurygaster integriceps, and E. maura. Extracts from male and female glands were analyzed using GC–MS, which revealed that (E)-2-hexen-1-ol acetate was the dominant compound in all four species. In addition, several α,β-unsaturated aldehydes with chain lengths of C6–C8, including (E)-2-hexenal, (E)-2-heptenal, (E)-2-octenal, and (E)-2-hexen-1-ol, were detected. These compounds are characterized by strong odors and irritant properties, acting as defensive allomones and alarm pheromones. Synthetic routes were developed for these key compounds. In particular, (E)-2-hexen-1-ol acetate was efficiently synthesized via acetylation of (E)-2-hexen-1-ol using acetic anhydride in the presence of 4-dimethylaminopyridine (DMAP) as a catalyst. This approach significantly reduced the reaction time to 30 min and improved the yield to 90%. Although DMAP is widely used in organic synthesis, the simplicity and efficiency of this optimized protocol for producing semiochemical analogues of stink bugs have not been previously reported. Preliminary trials with synthetic lures indicated their potential for pheromone-based monitoring of stink bug populations in cereal fields. The optimized semiochemical blends developed in this study are expected to contribute to integrated pest management strategies by enabling more effective detection and control of these economically important pests. Full article

Because animals threatened by visually oriented predators may respond in sun-lit daytime but not at night, invertebrate responses to predatory challenges may yield varying results based on the time period within the 24 h daily cycle. We predicted that in laboratory experiments aquatic isopods exposed to kairomones from predatory fish would spend more time immobilized in daylight to avoid detection than those not exposed to kairomones but that this difference would disappear under the cover of nighttime darkness. We further predicted that isopods in the absence of kairomones would move at elevated rates in the daytime compared with night, seeking a precautionary proximity to shelters. However, contrary to our predictions, Caecidotea communis isopods exhibited consistent activity (movement rate and proportion of time spent moving) when exposed to kairomones or in the absence of such cues, at all of the three diurnal cycle periods examined. Thus, Caecidotea communis displayed cathemerality (sometimes called metaturnality), the first documented case of this behavior in crustaceans. Full article

The banana weevil (Cosmopolites sordidus) is a significant pest that reduces banana yields and can result in plant mortality. (2R,5S)-theaspirane, a kairomone from senesced banana leaves, is one of the natural banana volatiles, aiding weevil attraction. A rapid and cost-effective synthesis of (2R,5S)-theaspirane was developed utilizing microwave-assisted conditions and the principles of green chemistry. The process comprised five steps, beginning with the reduction of dihydro-β-ionone, followed by lipase-mediated kinetic resolution to attain high enantiomeric excess. Microwave-assisted heating significantly reduced reaction times. Optimized cyclization with the minimum quantities of selenium dioxide oxidation was employed. The final diastereomers were separated by chromatography, yielding compounds which exceeded 99% enantiomeric purity. Full article

The Western Flower Thrips (Frankliniella occidentalis) constitutes a significant threat to rose greenhouses in Colombia. An eco-friendly approach to managing this pest involves using the predatory bug Orius insidiosus. The pest and its predator’s food search and selection mechanisms are influenced by ecological interactions mediated by volatile organic compounds (VOCs) emitted during plant–pest interactions. To investigate the role of VOCs in the foraging and host-selection behaviors of O. insidiosus, we conducted functional response assays in greenhouses and olfactometry experiments in laboratory settings. These experiments used flowers from two rose cultivars, with and without female adult thrips, over 24, 48, and 72 h. Functional response analysis revealed a shift in O. insidiosus foraging behavior based on the duration of thrips interaction with rose flowers, transitioning from a Type II to a Type III functional response between 24 and 48 h in the ‘Freedom’ cultivar. The maximum consumption rates increased significantly, from 7.98 individuals at 24 h to 16.18 individuals at 48 h, before slightly decreasing to 14.37 individuals at 72 h. This shift coincided with an increase in O. insidiosus preference for thrips-infested ‘Freedom’ flowers over time, with selection proportions rising from 0.37 at 24 h to 0.46 at 72 h, suggesting a learning effect on prey-searching behavior mediated by VOCs. Olfactometry analyses revealed that O. insidiosus did not respond to the same VOCs that attracted F. occidentalis during flower infestation. However, O. insidiosus responded to certain VOCs likely associated with floral resources such as nectar and pollen, which also attract pollinators and zoophytophagous predators. This observation suggests a potential overlap in the chemical cues used by O. insidiosus for distinct ecological purposes. These findings highlight the complex chemical ecology underlying predator–prey interactions in agroecosystems and underscore the importance of considering VOCs in shaping the foraging behavior of natural enemies and their interactions with insect pests. Full article

A four-component blend comprising pear ester, DMNT, linalool oxide, and acetic acid (CM4K) was identified as a potent allelochemical lure for both sexes of codling moth (CM), Cydia pomonella (L.). Studies conducted from 2020 to 2022 in Washington State (USA) examined factors which could impact the lure’s relative performance. The CM4K lure was effective across a range of mating disruption programs and was equally attractive in monitoring wild and sterile CM. The lure remained attractive for at least 10 weeks. Total catch in traps baited with the CM4K was significantly less impacted than a sex pheromone lure located near mating disruption dispensers and female catches were largely unaffected. Traps with the CM4K lure caught significantly more females and fewer males when placed near clusters of fruits in a trellised orchard. Two factors were found to significantly impact the relative performance of the CM4K to sex pheromone lures: the CM4K lure was only equivalent to sex pheromone lures in pear MD orchards, and apple and pear orchards with vigorous weed growth. This is the first report of a monitoring lure for a tortricid moth being negatively impacted by the background odor of non-host weed species present within an orchard. Full article

The poplar bark beetle Trypophloeus binodulus (Coleoptera: Scolytidae) is a key pest of poplar trees (Malpighiales: Salicaceae, genus Populus) across northern Spain. However, among the more than 200 poplar clones available on the market, the clone USA 184-411 has the highest susceptibility to T. binodulus attacks. We tested the hypothesis that compounds released by the most susceptible poplar clone chemically mediate Trypophloeus binodulus behavior. The leaf and bark volatile chemical profile composition of host poplar Populus nigra L. (Salicaceae) clones were analyzed and tested on adult T. binodulus by electroantennography (EAG) and by monitoring their populations in baited traps in northern Spain. The collection of volatiles released by the leaves and bark of both clones by SPME revealed the emission of 53 components from different chemical classes. Salicylaldehyde dominated these collections of leaf volatiles and was more abundant in aerations of the more susceptible poplar clone (USA 184-411). The EAG response of adult beetles to salicylaldehyde was higher than that of any other plant odorants. In field trials, traps baited with salicylaldehyde + ethanol significantly captured more adults than all other treatments, irrespective of other lure components. The present study could aid in developing semiochemical-based management tactics against this important pest. Full article