Search Results (220)

The genus Sclerodermus Latreille (Hymenoptera: Bethylidae) comprises over 80 species of ectoparasitoids of insect pests in forests, agricultural environments, and stored products with a cosmopolitan distribution. Despite its growing significance in biological control, behavioral ecology, and public health, the taxonomy of the genus remains poorly resolved. This is largely due to morphological reduction and simplification among species, outdated or incomplete original descriptions, and limited access to type material. A particularly problematic case is Sclerodermus cereicollis Kieffer, originally described from two geographically disjunct populations: Giglio Island (Italy, Palaearctic) and Annobón Island (Equatorial Guinea, Afrotropical). The syntype series includes morphologically divergent specimens, casting doubt on their conspecificity. In this study, we redescribe S. cereicollis based on both the original syntypes and newly collected material from Italy. A lectotype is designated to stabilize the nomenclature, and we provide the first molecular data for the species to assess genetic cohesion among populations. Comparative morphological and molecular analyses reveal that the Afrotropical syntypes represent a distinct, previously undescribed species. Accordingly, we describe Sclerodermus annobonensis Masini, Colombo & Azevedo sp. nov., designating a holotype. This study refines species boundaries within Sclerodermus and highlights the value of integrative taxonomy, combining historical and contemporary data, in resolving persistent systematic ambiguities in morphologically conservative taxa. Full article

Physical conditions in grain storage environments influence trophic interactions between predators and their prey and can affect the effectiveness of biocontrol agents. The study aimed to assess the potential of Xylocoris flavipes (Reuter) (Hemiptera: Anthocoridae), to manage Liposcelis decolor (Pearman) (Psocodea: Liposcelididae). Liposcelis decolor population suppression and X. flavipes progeny production were assessed at five predator–prey (P-P) ratios (0:240, 1:240, 2:240, 3:240, and 5:240), four temperatures (20, 24, 28, and 32 °C), and three relative humidities (RH) (63, 75, and 85%) over 40 days at 0:24 (L:D) photoperiod in the laboratory. Compared with the Control P-P ratio of 0:240 (no predators), prey suppression >97% was achieved across all predator release ratios. At 32 °C and 75% RH, which are the optimal conditions for L. decolor, 3985.13 ± 255.45 prey survived in the Control P-P ratio compared with 19.85 ± 2.47–115.73 ± 8.99 found for the four P-P ratios with the predator, representing prey reduction of 97.10–99.50%. Temperature influenced X. flavipes progeny production, which was greatest at 28 °C and a P-P ratio of 1:240. Suppression caused by X. flavipes demonstrates its potential as a biological control agent to manage psocid infestations in stored commodities. Full article

The present study highlights the critical role of surface type, insect species, and exposure duration in determining the efficacy of surface-applied insecticides in stored-product pest management. Four insecticides were sprayed and evaluated on different surfaces (concrete, metallic, plastic, and ceramic) against two beetles: the red flour beetle and the tobacco beetle. Alpha-cypermethrin and spinosad exhibited rapid and high efficacy, particularly on non-porous surfaces such as metal and ceramic, whereas pirimiphos-methyl was less effective initially and required extended exposure to achieve complete mortality, especially against Tribolium castaneum. In contrast, Lasioderma serricorne showed greater susceptibility across all insecticides and surfaces. Spinosad maintained high efficacy across all surface types, suggesting broader applicability under variable conditions. The reduced performance of insecticides on concrete surfaces underscores the influence of substrate porosity on insecticide bioavailability. Additionally, the observed delayed mortality effect in all treatments indicates that even brief exposure can result in lethal outcomes, emphasizing the long-term potential of these applications. These findings underscore the need for surface-specific application strategies and support the integration of surface treatments into comprehensive pest management programs. Further research is warranted under simulated field conditions to assess residual efficacy over time and in the presence of food, thereby enhancing the relevance of laboratory findings to real-world storage environments. Full article

We studied the characteristics of adult flat grain beetles Cryptolestes pusillus Schönherr in trap counts and their relationship with insect densities using electronic probe traps in experimental bins, which contained approximately 1.1 tons of paddy (Changlixiang) with moisture contents of 10.7% and 14.0% and insect densities of 0.1, 1.0, and 5.0 adults/kg. Inside each bin, we vertically installed three layers of electronic probe traps. We installed five traps at the center and half-radius of each layer of the bin. We undertook measurements of daily trap counts, grain temperature, and intergranular relative humidity at each trap location for up to 10 days, and 1.0 kg of paddy was collected from each trap location. At each of the introduced insect densities, we detected beetles using electronic probe traps. When insect density was 0.1 adults/kg, we could not detect the existence of insects in 1.0 kg samples. It was found that the trap counts were spatially nonuniformly distributed, and there was a weak correlation between different locations. There was a regularity in the temporal distribution of trap counts, which was significantly influenced by the paddy moisture content. Except for the insect density, the moisture content, grain temperature, and intergranular relative humidity at the trap location significantly affected trap counts. The distribution pattern of beetles in paddy bulks was found and aggregated by analyzing trap counts. There was a correlation between trap counts and insect densities in grain bulks, but this correlation varied significantly across different locations. Full article

Tomatoes are one of the most popular vegetables. The high level of production in the world is often offset by numerous losses that occur during production in the field or in the post-production stages. Preservation in its fresh form is a challenge, particularly due to pest attacks on stored food. A promising natural and inexpensive solution to protect against pests is the use of chitosan (CH), which can be associated with essential oils (EOs) with repellent effects. In previous studies, some protective effects have been demonstrated using chitosan films coated with EOs. In this study, we tested CH-EOs associations on tomato fruits to evaluate their efficacy against attacks by the pest Spodoptera littoralis (Boisduval, 1833), taking into account parameters such as age and body mass of the larvae and the effect over time (10 days) of the treatments. Our study highlights the potential of the combination of CH and cinnamon EO as an environmentally friendly solution to protect tomatoes from S. littoralis attack. Here we found a repellent effect of cinnamon EO combined with CH on S. littoralis larvae, with no effect on larval attractiveness or repellence for CH alone and the four other EOs tested. The main compound in cinnamon EO, (E)-cinnamaldehyde, had no overall repellent effect on larvae, but had specific effects when larval age, body mass, and post-treatment time were taken into account. Full article

Mating disruption is a commercially available management tactic for pyralid moths, which are pests of stored products. However, evaluations of efficacy have had limited replication, which limits the ability to draw conclusions about its effectiveness or the impact of different variables on its efficacy. We evaluated the mating disruption of Plodia interpunctella in 33 retail pet supply stores (6415 to 17,384 m³) and the impact of factors such as insect density and application rate on efficacy. Prior to starting MD, the average capture of P. interpunctella was 40.2 ± 3.6 moths/trap/month. Immediately after starting treatment, there was a sharp drop in captures (67.8 ± 4.8%) and then a more gradual overall downward. Overall, under mating disruption, the average reduction was 85.0 ± 3.0%. Geographic location, initial moth density, and pheromone application rate did not significantly impact efficacy. Analysis of the relationships between moth captures and mating disruption dispenser density indicated that competitive mechanisms were the primary mechanisms involved. This was the largest replicated assessment of MD for the management of a post-harvest pest and provides valuable foundational and applied insights into the process. Our results show that a standardized MD program can provide pest suppression in retail stores, but it takes time to be fully effective. Finally, identifying the primary mechanism for efficacy provides important information needed for further refinement of MD programs. Full article

Jasmonates have emerged as a prominent elicitor for enhancing trichome development and cannabinoid production in Cannabis sativa L. (cannabis). These glandular trichomes synthesize and store important cannabinoids, including tetrahydrocannabinol (THC) and cannabidiol (CBD), which determine the yield, potency, and quality of cannabis flowers. Methyl jasmonate (MeJA) acts through the COI1–JAZ–MYC signaling pathway to upregulate genes associated with trichome initiation and cannabinoid precursor formation. Evidence suggests that moderate MeJA concentrations (typically 50–100 µM) can effectively boost trichome density, elevate hexanoyl-CoA availability, and modestly enhance key biosynthetic enzyme activities, ultimately increasing THC and CBD content. However, higher methyl jasmonate doses can amplify these benefits, yet pose a risk of excessive vegetative stunting, highlighting the crucial trade-off between enhancing cannabinoid potency and maintaining overall biomass yield. Interaction with hormones like gibberellins, salicylic acid, and ethylene further shapes the plant’s stress responses and secondary metabolism. Application in controlled environments, such as greenhouses or vertical farms, shows promise for enhancing resin production while minimizing biomass loss. In outdoor conditions, the application may offer additional defense benefits against pests and pathogens. These responses can vary depending on the cultivar, underscoring the importance of cultivar-specific optimization. As demand for high-cannabinoid cannabis products continues to grow and agrochemical options remain limited, leveraging MeJA treatments offers a practical, non-genetically modified approach to optimize yield, quality, and resilience in cannabis cultivation. Full article

Effective stored-grain insect pest detection is crucial in grain storage management to prevent economic losses and ensure food security throughout production and supply chains. Existing detection methods suffer from issues such as high labor costs, environmental interference, high equipment costs, and inconsistent performance. To address these limitations, we proposed PDA-YOLO, an improved stored-grain insect pest detection algorithm based on YOLO11n which integrates three key modules: PoolFormer_C3k2 (PF_C3k2) for efficient local feature extraction, Attention-based Intra-Scale Feature Interaction (AIFI) for enhanced global context awareness, and Dynamic Multi-scale Aware Edge (DMAE) for precise boundary detection of small targets. Trained and tested on 6200 images covering five common stored-grain insect pests (Lesser Grain Borer, Red Flour Beetle, Indian Meal Moth, Maize Weevil, and Angoumois Grain Moth), PDA-YOLO achieved an mAP@0.5 of 96.6%, mAP@0.5:0.95 of 60.4%, and F1 score of 93.5%, with a computational cost of only 6.9 G and mean detection time of 9.9 ms per image. These results demonstrate the advantages over mainstream detection algorithms, balancing accuracy, computational efficiency, and real-time performance. PDA-YOLO provides a reference for pest detection in intelligent grain storage management. Full article

Bacillus thuringiensis is widely utilized as a microbial insecticide due to its production of parasporal crystals during the spore-forming stage. However, lower fermentation efficiency coupled with elevated production costs limit its broad application. Low-frequency ultrasound (LFU) has been employed in the fermentation industry to enhance microbial growth and metabolism. In this study, the effect of LFU on the growth of B. thuringiensis HD1 and the yields of parasporal crystals was investigated. The maximum biomass accumulation of Bacillus thuringiensis and parasporal crystal production yield were achieved following low-frequency ultrasonic (LFU) treatment applied during the logarithmic growth phase (18 h of cultivation) under optimized parameters: a frequency of 40 kHz, a power output of 176 W, and an irradiation duration of 45 min. Under optimal conditions, LFU significantly increased the cell membrane permeability and secretory inositol, favoring cell growth and parasporal crystal production. FESEM/CLSM and TEM analyses visually displayed the changes in cell morphology. In addition, the germination rate of spores was increased after LFU treatment, which further confirmed the positive effect of LFU on the growth of B. thuringiensis. Compared to the control, parasporal crystals harvested under LFU exhibited significant modifications in their physicochemical characteristics; the particle size increased, the surface electronegativity intensified, and there was a morphological transition from spherical to cubic geometry. Importantly, the parasporal crystals exhibited strong insecticidal activity against S. zeamais adults, a typical stored-product insect pest, with an LC₅₀ of 10.795 mg/g on day 14 and a Kt₅₀ of 4.855 days at a concentration of 30 mg/g. These findings will provide new insights into the product development and application of B. thuringiensis in the future. Full article

Stored product pests are controlled primarily through applying pyrethroid and organophosphate insecticides or through fumigation with phosphine (PH₃). However, several populations of weevils are resistant to these insecticides. Essential oils appear to be safe alternatives for both humans and the environment. The objective was to investigate the toxicity of Piper aduncum essential oil (PAEO) to Sitophilus zeamais and evaluate its effects on corn grain quality during the four-month storage period. This study was conducted in two stages. In the first stage, the toxicity of PAEO at concentrations lethal to 50 and 95% of insects (LC₅₀ and LC₉₅) was estimated. The second step evaluated the degree of infestation, water content, apparent specific mass, loss of mass, electrical conductivity, and percentage of germination of grains at 0, 30, 60, 90, and 120 days after exposure to PAEO, deltamethrin (pyrethroid), and the control treatment. PAEO presents toxicity to S. zeamais. The LC₅₀ and LC₉₅ values are 298.50 µL kg⁻¹ and 585.20 µL kg⁻¹, respectively. The increases in infestation degree, water content, electric conductivity, and mass loss, as well as reductions in apparent specific mass and germination, show the loss of corn quality during the 120-day storage period, being more significant when no product is applied. PAEO delays the loss of quality of the grains, presenting a greater capacity to preserve the grains for a longer period. Full article

Araecerus fasciculatus (De Geer, 1775) is an important stored-product pest worldwide. In this study, the development time, survival rate, oviposition, and digestive enzyme (α-amylase, cellulase, pepsin, and lipase) activities of A. fasciculatus fed on five commodities (coffee, jujube, maize, wheat, and kansui) were investigated. Our results showed that the developmental duration of A. fasciculatus from egg to adult was shortest on coffee beans (51.41 days) and longest on kansui (69.65 days). The survival rate of A. fasciculatus adults was lowest on kansui (42.22%) and highest on coffee beans (63.33%). Significant differences in fecundity were also observed, with the greatest number on coffee beans (80.78 eggs/female) and the lowest on kansui (50.43 eggs/female). Araecerus fasciculatus showed the greatest intrinsic rate of natural increase (r_m) on coffee beans (0.141), followed by jujube (0.129), maize (0.117), wheat (0.105), and kansui (0.097). The net productive rate (R₀) showed a similar trend to r_m, with values of 48.42, 42.53, 35.39, 27.53, and 21.47, respectively, on these stored products. Although no significant differences were observed in the lipase activities when A. fasciculatus was fed on different stored products, activities of α-amylase, pepsin, and cellulase were highest on coffee beans and lowest on kansui. The variation in the population development of A. fasciculatus associated with different foods may be related to its digestive enzyme performance. These results indicated that coffee beans were the most suitable host food, while kansui was the least suitable for the development of A. fasciculatus. Full article

Diatomaceous earth (DE) consists of fossilized remnants of diatoms, which are marine or freshwater unicellular algae. Most DEs originate from fossilized sedimentary layers of diatoms deposited in water bodies during the Eocene and Miocene periods, much more than 20 million years ago. Processed DE, a soft, chalky powder, is widely used as an insecticide due to the highly absorptive and abrasive nature of its particles. As an insecticide, DE removes the wax coating of the insect epicuticle, the primary barrier against water loss. This results in water evaporation, leading to desiccation and death of the targeted insects. This review emphasizes the co-treatment of DEs with biological agents that have insecticidal properties (e.g., essential oils, plant powders, silica gel, and species/isolates of fungi), reducing the quantities used in single-application treatments and suggesting paths for the sustainable management of insects damaging stored products. Full article

With over 1000 species of pests causing losses in both the quantity and quality of stored food, insect contamination poses significant challenges. The present study assesses the efficacy of the combination of λ-cyhalothrin and chlorantraniliprole against four key storage pests—Trogoderma granarium, Sitophilus oryzae, Rhyzopertha dominica, and Tribolium castaneum. Laboratory bioassays demonstrated species-dependent mortality, with S. oryzae and R. dominica suffering 100% mortality in several tested scenarios. A 90-day persistence trial revealed decreased efficacy over time, especially for T. granarium (32.0–71.4% at 0 days and 0.0–7.5% at 90 days) and T. castaneum (38.8–82.7% at 0 days and 0.0–12.7% at 90 days) vs. S. oryzae and R. dominica. Progeny production of S. oryzae and R. dominica was almost suppressed in persistence trials (0.4 individuals per vial and 1 individual per vial, respectively) after 30 days of storage at the dose of 5 mg/kg wheat. The results highlight the variability in insecticidal performance based on species, dose, exposure, and commodity type, emphasizing the need for tailored pest management strategies in the storage environment. Full article

Biological control by releasing a large number of parasitoids has been an effective strategy for coping with stored-product pest insects. Habrobracon hebetor (Say) (Hymenoptera: Braconidae) has strong control capabilities over Lepidoptera pests. Exploring the optimum storage temperature, life stage, and cold storage period of H. hebetor is of great importance for the utilization of parasitoids. In this context, the survival, parasitism, and fecundity of H. hebetor were evaluated after 10, 20, 30, 40, 50, and 60 d of exposure at −5, 0, 5, 10, and 15 °C for H. hebetor eggs, larvae, pupae, and adults, and the survival, parasitism, and fecundity of H. hebetor individuals that had been maintained at normal rearing condition were taken as a control. The cold exposure duration dramatically affected the development and survival of eggs, larvae, and pupae of H. hebetor, regardless of the temperatures tested. Habrobracon hebetor eggs, larvae, and pupae failed to develop into the next life stage at −5, 0, and 5 °C. Habrobracon hebetor eggs, larvae, pupae, and adults failed to survive after 10 d exposure at −5 and 0 °C. The parasitism rate, fecundity and oviposition duration of H. hebetor adults that originated from eggs, larvae, pupae, and adults after different cold storage durations markedly decreased with increasing cold storage duration. The highest parasitism rate of adults was 34.12% after exposure at 5 °C for 10 d, which was not significantly different from the control (31.86%). The maximum level of egg production of H. hebetor adults developed from initial larvae exposed at 15 °C for 10 d and 20 d were 344.67 and 340.67 eggs/female, respectively, which were not significantly different from the control (392.00 eggs/female). When H. hebetor larvae were stored at 15 °C for 10 and 60 d, the oviposition duration of newly emerged adults reached the maximum and minimum levels recorded, with 17.00 and 0.83 d, respectively. These results provide empirical support for the large-scale production and storage of H. hebetor. Full article

Endosymbiotic bacteria are key factors that regulate the biological traits of Liposcelis bostrychophila. This study employed metagenomic methods to analyze the dominant species of symbiotic microorganisms associated with L. bostrychophila. By controlling the environmental temperature, we were able to manipulate the abundance of endosymbionts and establish populations with high, medium, and low levels of these bacteria. This allowed us to examine the fitness parameters of L. bostrychophila under different levels of endosymbiont abundance. The experimental results revealed that L. bostrychophila hosts 51 genera of symbiotic microorganisms, with Rickettsia being the dominant genus, accounting for 84.11% to 98.16% of the total share. Environmental temperature significantly affected the abundance of Rickettsia, with notable differences observed during the adult stage of L. bostrychophila. A temperature gradient of 28 °C, 35 °C, and 37 °C was established, allowing for the classification of populations based on Rickettsia abundance into three categories: high-abundance populations (LBhp), medium-abundance populations (LBmp), and low-abundance populations (LBlp). The abundance of Rickettsia had a significant impact on the fitness of L. bostrychophila. Specifically, a high abundance of Rickettsia contributed positively to population fitness by increasing egg production, prolonging egg hatching time, enhancing lifespan, and improving both survival and reproductive rates. Therefore, the endosymbiont Rickettsia plays a crucial role in the growth and development of L. bostrychophila. In the future, our research will help further uncover the interactions between Rickettsia and its host, providing new perspectives for pest control and offering a better understanding of insect biology and ecology. Full article