In the contact trial, APCO exhibited a significantly stronger escape response (11:1 ratio, 7018%) against the field strain than DEET (3833%), a difference statistically significant (p<0.005). All combinations of VZCO against the laboratory strains (667-3167%) exhibited a weak, non-contact escape strategy. The potential for VZ and AP as active repellent ingredients, based on these findings, may necessitate further development before human trials.
Tomato spotted wilt virus (TSWV), a destructive plant virus, leads to substantial economic losses in high-value crop production. The western flower thrips, Frankliniella occidentalis, and other specific thrips are vectors for this virus. The process of young larvae feeding on infected plants leads to their acquisition of TSWV. TSWV, through unknown receptor mechanisms, infects the gut epithelium, multiplies within host cells, and then spreads horizontally to other host plants via the salivary glands during the vector's feeding activity. Proteins glycoprotein (Fo-GN) and cyclophilin (Fo-Cyp1), located within the alimentary canal, are suspected to be crucial in enabling TSWV infection of the gut epithelium in F. occidentalis. By fluorescence in situ hybridization (FISH), Fo-GN's transcript, possessing a chitin-binding domain, was shown to be situated within the larval gut epithelium. A phylogenetic study indicated the presence of six cyclophilin genes within the *F. occidentalis* genome, specifically highlighting the close evolutionary relationship between Fo-Cyp1 and human cyclophilin A, an important regulator of immune function. In addition to other transcripts, Fo-Cyp1 was also detected in the larval gut epithelium. RNA interference (RNAi) specific to these two genes, when fed to young larvae, resulted in their expression suppression. The RNAi efficiencies were established by FISH analyses, which identified the eradication of the target gene transcripts from the gut epithelium. RNAi treatments targeting Fo-GN or Fo-Cyp1 inhibited the usual rise in TSWV titer post-virus feeding, contrasting with the control RNAi treatment. Our immunofluorescence assay, specifically targeting TSWV with a designated antibody, indicated a decline in TSWV presence in both the larval gut and the adult salivary gland after RNAi treatment. These outcomes lend credence to our hypothesis that the candidate proteins, Fo-GN and Fo-Cyp1, are instrumental in both the invasion and replication of TSWV in F. occidentalis.
Field beans, a crop crucial to the diversification of European farming systems, are negatively impacted by the destructive presence of broad bean weevils (BBWs), a Coleoptera Chrysomelidae species. Scientific studies have uncovered distinct semiochemical attractants and trapping devices for the purpose of implementing comprehensive semiochemical-based control measures against BBWs. In order to inform the implementation of sustainable field practices utilizing semiochemical traps for BBW control, this study comprised two field trials. This study was driven by three central objectives: (i) to identify the most effective traps for BBW capture and determine how trapping methods influence BBW sex ratios; (ii) to evaluate potential secondary effects on crop productivity, encompassing the impact on beneficial insects such as aphid predators and pollinators including bees, hoverflies, and ladybirds; and (iii) to assess how the developmental stage of the crop affects capture by semiochemical traps. In two field trials, covering both early and late blooming stages of field bean crops, three various semiochemical lures were examined in conjunction with two different trapping mechanisms. The spatiotemporal development of the captured insect populations was interpreted through the analyses, using crop phenology and climate parameters. 1380 BBWs and 1424 beneficials were seized in total. Floral kairomones, coupled with white pan traps, proved to be the most effective method for capturing BBWs. Our investigation highlighted the substantial competition exerted by the crop's phenology, specifically the flowering stage, on the attractiveness of the semiochemical traps. Examination of the community within field bean crops demonstrated a singular capture of the BBW species Bruchus rufimanus, without any notable trends in sex ratios related to trapping methods. A diverse community of beneficial insects, encompassing 67 species, comprised bees, hoverflies, and ladybeetles. Semiochemical traps, while effective, exerted a significant influence on beneficial insect populations, encompassing species facing extinction risks, necessitating further adaptation to mitigate such unintended consequences. From these results, we derive recommendations for the implementation of a sustainable BBW management approach that minimizes disruption to beneficial insect recruitment, critical for the success of faba bean agriculture.
China's tea industry faces substantial damage from the stick tea thrips, D. minowai Priesner (Thysanoptera Thripidae), a significant pest of Camellia sinensis (L.) O. Ktze. To characterize the activity patterns, population dynamics, and spatial distribution of D. minowai, we collected samples from tea plantations between 2019 and 2022. Traps positioned at elevations between 5 centimeters below and 25 centimeters above the apical tender leaves on the tea plants yielded a high proportion of D. minowai. The largest number of D. minowai were captured at a height of 10 centimeters from the uppermost tender foliage. Thrips exhibited highest densities during the spring hours of 1000 to 1600, and during the summer's sunny hours, from 0600 to 1000 and again from 1600 to 2000. IMT1B The aggregation pattern of D. minowai females and nymphs on leaves corresponded to Taylor's power law (females R² = 0.92, b = 1.69 > 1; nymphs R² = 0.91, b = 2.29 > 1) and Lloyd's patchiness index (females and nymphs, displaying C > 1, Ca > 0, I > 0, M*/m > 1). A significant female majority characterized the D. minowai population, alongside a subsequent rise in male density during the month of June. On the undermost leaves, adult thrips, having overwintered, enjoyed their greatest abundance between the months of April and June, and subsequently from August to October. The outcomes of our investigation will be valuable in developing strategies to manage D. minowai numbers.
Of all entomopathogens, Bacillus thuringiensis (Bt) proves itself to be the most economically viable and safest option. Lepidopteran pest control employs the extensive production of transgenic crops, or spray formulations as a means to eradicate these pests. The sustained employment of Bt is endangered by the development of insect resistance. The ability of insects to withstand Bt toxins is contingent upon not merely receptor alterations, but also augmented immune responses within the insect. Lepidopteran pest susceptibility to Bt and associated immune responses are evaluated in this review of current knowledge. IMT1B Investigating the mechanism of immune response reactions or resistance to Bt, we discuss the pattern recognition proteins for identifying Bt toxins, antimicrobial peptides (AMPs) and their synthetic signaling pathways, the prophenoloxidase system, reactive oxygen species (ROS) generation, nodulation, encapsulation, phagocytosis, and cell-free aggregates. This examination also explores immune priming, a key element in the evolution of insect resistance to Bt, and offers strategies for boosting Bt's insecticidal action and managing insect resistance, focusing on the insect's immune system and resistance mechanisms.
The cereal pest Zabrus tenebrioides is causing increasing damage and is becoming a major problem in the Polish agricultural industry. The pest's control seems likely to benefit from the very promising action of entomopathogenic nematodes (EPNs). Native EPN populations have evolved to thrive in the precise environmental circumstances of their region. Differing efficacies against Z. tenebrioides were observed in three Polish Steinernema feltiae isolates, as detailed in the current study. The pest population in the field was reduced by 37% with the Iso1Lon isolate, contrasting with a 30% reduction with Iso1Dan and no reduction with Iso1Obl. IMT1B Following a 60-day soil incubation period, recovered EPN juveniles from all three isolates demonstrated the capacity to infect 93-100% of the test insects; however, isolate iso1Obl exhibited the lowest infection efficacy. Morphometrical variations were observed in the juveniles of isolate iso1Obl, set apart from the other two isolates through principal component analysis (PCA), which effectively separated the EPN isolates. Findings from this research stressed the importance of implementing locally adapted EPN isolates; two randomly selected isolates from Polish soil performed better than a commercially sourced S. feltiae strain.
A global menace, the diamondback moth (Plutella xylostella), inflicts considerable damage on brassica crops, proving stubbornly resistant to a large selection of insecticides. Another possibility, the utilization of pheromone-baited traps, has been suggested, although farmers remain skeptical. We investigated the potential benefits of employing pheromone-baited traps for monitoring and mass trapping in Central American cabbage production, positioning it within an Integrated Pest Management (IPM) framework, compared to the presently used schedule-driven insecticide spray applications by farmers. Nine selected cabbage plots in Costa Rica and Nicaragua underwent a mass trapping procedure. The effectiveness of Integrated Pest Management (IPM) plots, measured by average male insect captures per trap per night, plant damage, and net profit, was contrasted with results obtained from, or drawing on, contemporaneous or previously documented records of plots using conventional pest control (FCP). Trap capture results in Costa Rica demonstrated that insecticide use was unnecessary, and this resulted in an average net profit increase exceeding 11% upon the implementation of the new trapping strategies. A noteworthy reduction in insecticide applications was observed in IPM plots of Nicaragua, specifically one-third that of FCP plots. These results unequivocally demonstrate the combined economic and environmental advantages of pheromone-based DBM control strategies in Central America.