An insecticide containing the neonicotinoid thiamethoxam + the diamide chlorantraniliprole was evaluated against adults of Rhyzopertha dominica, Tribolium castaneum, Trogoderma granarium, and Sitophilus oryzae under laboratory bioassays both on freshly treated grain as well as on treated grain stored over 90 days for its persistence in efficacy. In laboratory bioassays, the insecticide was applied on wheat, maize, or rice at four doses, while in persistence bioassays on wheat at the same doses. Mortality and progeny were assessed in both laboratory and persistence bioassays. After 14 days of exposure, S. oryzae exhibited 100% mortality on all three commodities at the highest dose, while R. dominica showed complete mortality on wheat or rice and T. castaneum on wheat. For a period of 90 days, S. oryzae exhibited 42.69% mortality, followed by R. dominica (35.26%), T. castaneum (27.08%), and T. granarium (18.63%) at the highest dose. Progeny was successfully suppressed in all cases of complete mortality in laboratory bioassays and for S. oryzae for 90 days in persistence bioassays. Laboratory trials were also performed on plywood, concrete, ceramic tile, and steel at one dose. The highest mortality was observed on steel, followed by concrete, ceramic tile, and plywood for all insect species tested. This study demonstrates that thiamethoxam + chlorantraniliprole is effective against the tested species depending on exposure, storage period, surface, commodity, and dose. Full article

Cheyletus malaccensis Oudemans and Cheyletus eruditus (Schrank) are predators of stored-grain pests in China. The psocid Liposcelis bostrychophila Badonnel is prone to outbreaks in depots. To assess the potential of large-scale breeding with Acarus siro Linnaeus and the biological control potential of C. malaccensis and C. eruditus against L. bostrychophila, we determined the development times of different stages at 16, 20, 24, and 28 °C and 75% relative humidity (RH) while feeding on A. siro, as well as the functional responses of both species’ protonymphs and females to L. bostrychophila eggs at 28 °C and 75% RH. Cheyletus malaccensis had a shorter development time and longer adult survival time than C. eruditus at 28 °C and 75% RH and could establish populations faster than C. eruditus while preying on A. siro. The protonymphs of both species showed a type II functional response, while the females showed a type III functional response. Cheyletus malaccensis showed a higher predation ability than C. eruditus, and the females of both species had a higher predation ability than the protonymphs. Based on the observed development times, adult survival times, and predation efficiency, Cheyletus malaccensis has much greater biocontrol potential than C. eruditus. Full article

Tenebrio molitor L. (Coleoptera: Tenebrionidae), Prostephanus truncatus (Horn), and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) are noxious insect pests of grains in storages. Pirimiphos-methyl is widely used to protect grains at the post-harvest stage. However, the sub-lethal impact of this active ingredient on the offspring of all three coleopterans remains unknown. Thus, mated females of each species were exposed separately to pirimiphos-methyl at short exposures (30 min, 3, 5, 8, 16, 24, and 36 h), where the elytra and hindwings of the adult progeny were analyzed with the geometric morphometrics method. Males and females of all species were incorporated into the analysis. The results revealed variability among species. Tenebrio molitor was the most sensitive among three species, displaying significant deformations in the elytra and hindwings. Males had more conspicuous morphological changes than females. Prostephanus truncatus hindwings exhibited deformities after 36 h of exposure to pirimiphos-methyl. In contrast, R. dominica offspring were not affected by pirimiphos-methyl. In light of our findings, organophosphorus insecticides may cause variable sub-lethal effects to stored-product insects. This issue may lead to different insecticidal treatments according to the targeted stored-product species. Full article

Ethiopian subsistence farmers traditionally store their grain harvests, leaving them open to storage pests and fungi that can cause contamination of major staple crops. Applying the most effective strategy requires a precise understanding of the insect species, infestation rates, storage losses, and storage conditions in the various types of farmers’ grain stores. This study did a complete literature analysis on post-harvest pest and management measures with a focus on Ethiopia. The most frequent insect pests of stored cereals in this study were weevils (Sitophilus spp.), the lesser grain borer (Rhyzopertha dominica), rust-red flour beetle (Tribolium sp.), sawtoothed grain beetle (Oryzaephilus sp.), grain beetle (Cryptolestes spp.), Indian meal moth (Plodia interpunctella), and Angoumois grain moth (Sitotroga cerealella). Flour beetles (Tribolium spp.), sawtoothed beetles (Oryzaephilus sp.), flat grain beetles (Cryptolestes pusillus), and some moths have been identified as common stored product pests of stored oil seed, while bruchid beetles (Callosobruchus chinensis) and the moths were reported for pulses. Additionally, the storage pests in Ethiopia under varied conditions caused storage losses of 9–64.5%, 13–95%, 36.9–51.9%, and 2–94.7% in maize, sorghum, chickpeas, and sesame, respectively. To reduce the losses incurred, preventative measures can be taken before infestations or as soon as infestations are discovered. A variety of pest population monitoring systems for harvested products and retailers have been developed and recommended. In this context, reducing post-harvest grain losses is an urgent concern for improving food accessibility and availability for many smallholder farmers in Ethiopia and ensuring the nation’s long-term food security. Full article

The rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae), is a serious secondary pest of stored and processed food commodities. In the present study, we investigated the lateralization of males during courtship and mating, attempting to understand if it can be linked with a high likelihood of successful copulation. Most males exhibited left-biased (41%) approaches towards females, and turned 180° to their left, with 37% mating success. Right-biased males (i.e., approaching from the right and then turning 180°) were fewer than left-biased ones; 26% out of 34% managed to copulate with females. Only 9% out of 13% and 7% out of 11% of the back side- and front side-approaching males succeeded in mating, respectively. Directional asymmetries in approaching a potential mate, as well as the laterality of side-biased turning 180°, significantly affected male copulation success, with left-biased males achieving higher mating success if compared to right-biased males. Copula duration was significantly lower for left-biased-approaching males (1668.0 s) over the others (i.e., 1808.1, 1767.9 and 1746.9 for right-biased, front and back side-males, respectively). Left-biased males performed shorter copulation attempts and copula compared to right-biased males. Overall, our study adds basic knowledge to the lateralized behavioral displays during courtship and copula of C. ferrugineus. Full article

The lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) is an important stored-product pest for the poultry industry as it is a vector of dangerous pathogens for humans. In the present study, we evaluated the short- and long-term mortalities of small and large larvae of A. diaperinus when they were exposed to concrete-covered Petri dishes treated with etofenprox, deltamethrin, and the combination of piperonyl butoxide+acetamiprid+d-tetramethrin. Small and large larvae were exposed to each insecticide applied on concrete surfaces with or without food. The short-term mortality was recorded after 1 day, 3 days, 5 days, and 7 days, while the long-term mortality was recorded 7 days after the transport of the larvae alive to pesticide-free concrete-covered dishes. Regarding short-term mortality levels, 97.8% and 80.0% of the small and large larvae, that were exposed to etofenprox without food, died after 7 days of exposure, respectively. Concerning deltamethrin, all tested small larvae were killed after 3 days (without food) and 5 days (with food) of exposure. For large larvae, deltamethrin caused 98.9% (with food) and 100.0% (without food) mortality levels after 5 days of exposure. The combination of piperonyl butoxide+acetamiprid+d-tetramethrin caused high mortality levels to small larvae, i.e., 84.4% and 100.0% on dishes with and without food, respectively, but low to moderate mortality levels to large larvae that did not exceed 67.8% after 7 days of exposure. Long-term mortality varied vastly among the tested insecticides. Etofenprox killed 100.0% of the small larvae on concrete without food, but 24.0% of the large larvae exposed to concrete containing food. Deltamethrin did not provide long-term mortality to large larvae when food was present. Piperonyl butoxide+acetamiprid+d-tetramethrin caused mortality rates that overall varied from 33.5% (large larvae on concrete with food) to 85.0% (small larvae on concrete with food). In conclusion, deltamethrin killed almost all exposed larvae at exposures of ≤5 days, regardless of their size and the presence of food on the concrete. Full article

Odorant-degrading enzymes (ODEs) play an important role in rapidly degrading and inactivating odorant molecules that have completed information transmission, as well as in maintaining the stability and sensitivity of insect olfactory sensing systems. Glutathione S-transferases (GSTs), as a group of ODEs, supposedly bear the ability to catalyze the conjugation of glutathione (GSH) and xenobiotic odorant molecules in the degrading process. However, there are few reports regarding the role of the GST genes of Sitophilus zeamais in the degrading process. Thus, we characterized 13 full-length genes encoding GST sequences from S. zeamais, of which only SzeaGSTd1 contained a high abundance in the antennae. Ligand-binding assays implied that SzeaGSTd1 was able to catalyze the conjugation of GSH with 2, 4-dinitrochlorobenzene (CDNB). We investigated whether recombinant SzeaGSTd1 bears the ability to degrade the volatile molecules of the host; among the host volatiles, and found capryl alcohol to be a suitable substrate for SzeaGSTd1. These results strongly suggest that SzeaGSTd1 probably plays a role in auxiliary host location by degrading the host volatiles of capryl alcohol and exhibits a potential biological function in the olfactory sensing system of S. zeamais. Knowledge of the potential functions of SzeaGSTd1 will provide new ideas for biological control strategies for S. zeamais. Full article

The selective application of insecticides is one of the cornerstones of integrated pest management (IPM) and management strategies for pest resistance to insecticides. The present work provides a comprehensive overview of the traditional and new methods for the application of gas, liquid, gel, and solid physical insecticide formulations to control stored-product and food industry urban pests from the taxa Acarina, Blattodea, Coleoptera, Diptera, Hymenoptera, Lepidoptera, Psocoptera, and Zygentoma. Various definitions and concepts historically and currently used for various pesticide application formulations and methods are also described. This review demonstrates that new technological advances have sparked renewed research interest in the optimization of conventional methods such as insecticide aerosols, sprays, fumigants, and inert gases. Insect growth regulators/disruptors (IGRs/IGDs) are increasingly employed in baits, aerosols, residual treatments, and as spray-residual protectants for long-term stored-grain protection. Insecticide-impregnated hypoxic multilayer bags have been proven to be one of the most promising low-cost and safe methods for hermetic grain storage in developing countries. Insecticide-impregnated netting and food baits were originally developed for the control of urban/medical pests and have been recognized as an innovative technology for the protection of stored commodities. New biodegradable acaricide gel coatings and nets have been suggested for the protection of ham meat. Tablets and satchels represent a new approach for the application of botanicals. Many emerging technologies can be found in the form of impregnated protective packaging (insect growth regulators/disruptors (IGRs/IGDs), natural repellents), pheromone-based attracticides, electrostatic dust or sprays, nanoparticles, edible artificial sweeteners, hydrogels, inert baits with synthetic attractants, biodegradable encapsulations of active ingredients, and cyanogenic protective grain coatings. Smart pest control technologies based on RNA-based gene silencing compounds incorporated into food baits stand at the forefront of current strategic research. Inert gases and dust (diatomaceous earth) are positive examples of alternatives to synthetic pesticide products, for which methods of application and their integration with other methods have been proposed and implemented in practice. Although many promising laboratory studies have been conducted on the biological activity of natural botanical insecticides, published studies demonstrating their effective industrial field usage in grain stores and food production facilities are scarce. This review shows that the current problems associated with the application of some natural botanical insecticides (e.g., sorption, stability, field efficacy, and smell) to some extent echo problems that were frequently encountered and addressed almost 100 years ago during the transition from ancient to modern classical chemical pest control methods. Full article

Microbes are ubiquitous and play important ecological roles in a variety of habitats. While research has been largely focused on arthropods and microbes separately in the post-harvest supply chain, less attention has been paid to their interactions with each other. Up to this point, there has been no attempt to systematically describe the patterns of behavioral responses by stored-product insects to microbially produced volatile organic compounds (MVOCs). Thus, our aims were to evaluate whether stored-product arthropods were primarily and significantly attracted, repelled, or had a net neutral effect (e.g., unaffected or mixed) by MVOCs presented as (1) complex headspace blends or (2) single constituents and known mixtures. In total, we found 43 articles that contained 384 sets of tests with different combinations of methodology and/or qualitative findings, describing the behavioral responses of 24 stored-product arthropod species from two classes, four orders, and 14 families to 58 individual microbial compounds and the complex headspace blends from at least 78 microbial taxa. A total of five and four stored-product arthropod species were significantly attracted and repelled by MVOCs across odor sources, respectively, while 13 were unaffected or exhibited mixed effects. We summarize the biases in the literature, including that the majority of tests have occurred in the laboratory with a limited subset of methodology and has largely only assessed the preference of adult arthropods. Finally, we identify foundational hypotheses for the roles that MVOCs play for stored-product arthropods as well as gaps in research and future directions, while highlighting that the behavioral responses to MVOCs are complex, context-, and taxon-dependent, which warrants further investigation. Full article

The control of insect pests often relies on the recurrent application of insecticides. This is the case for the lesser mealworm, Alphitobius diaperinus, an invasive beetle infesting poultry farms. There is evidence that A. diaperinus can develop resistance to several insecticides. Evaluation of such resistance has never been conducted in France, despite the beetle’s presence since the 1970s. We assess insecticide susceptibility in 10 populations from French poultry farms and compare patterns with two susceptible populations. Adults are subjected to short-term exposures (4 h) to four commercial insecticides and their recovery is assessed. Temporal survival also is scored during constant exposures for seven days. Clear-cut differences among the farm populations are found. Except for three populations that have patterns similar to those of the two susceptible populations, all the other farm populations have a much greater capacity to recover and survive insecticide exposures, especially to pyrethroid-based formulations. Three populations in particular even exhibit clear signs of resistance to pyrethroids, with median lethal times more than 10-fold superior to values of the susceptible population. No insect in any population recovers from the pirimiphos-methyl exposure, and all beetles are apparently dead after 15 h. Our results demonstrate the existence of resistant populations to pyrethroids in Brittany France. Full article

In Pakistan, the control of stored-product insect pests mainly relies on the use of phosphine gas along with other control tactics. The aim of this study was to determine the level of phosphine resistance among ten differently located populations of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae), the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae). Laboratory-susceptible populations of all insect species were also considered in the experiments. Concentration–response bioassays were conducted for each species. All of the tested populations (10 out of 10) of each species were found to be resistant to phosphine, but varied in their level of resistance. Probit analysis estimated LC₅₀ at 2.85, 1.90, 2.54 and 2.01 ppm for laboratory-susceptible populations of R. dominica, S. granarius, T. castaneum and T. granarium, respectively. Against R. dominica, the highest and lowest resistance levels were observed in the Rahim Yar Khan (LC₅₀ at 360.90 ppm) and Rawalpindi (LC₅₀ at 210.98 ppm) populations, respectively. These resistant populations were 126.67- and 74.02-fold more resistant than the laboratory population. The Multan and Lahore populations of S. granarius exhibited the maximum (LC₅₀ at 122.81 ppm) and minimum (LC₅₀ at 45.96 ppm) resistance levels, respectively, i.e., they were 64.63- and 24.18-fold more resistant than the laboratory population. The Layyah population of T. castaneum showed the maximum resistance level (LC₅₀ at 305.89 ppm) while the lowest was observed in the Lahore population (LC₅₀ at 186.52 ppm), corresponding to 120.42- and 73.43-fold more resistant than the laboratory population, respectively. Regarding T. granarium, the Layyah population showed the maximum resistance level (LC₅₀ at 169.99 ppm) while the Lahore population showed the minimum resistance (LC₅₀ at 74.50 ppm), i.e., they were 84.57- and 37.06-fold more resistant than the laboratory population, respectively. Overall, R. dominica presented the highest resistance level, followed by T. castaneum, T. granarium and S. granarius. The current study suggests that the application of phosphine may not be an adequate control strategy for the management of the above tested insect pests in Pakistan. Full article

The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) is one of the most destructive insect pests of stored maize and dried tubers of cassava, and a wood-boring species. In the present study, we examined two chlorantraniliprole formulations, WG (wettable granule) with 350 g/kg active ingredient (a.i.) and SC (suspension concentrate) with 200 g/L a.i., as maize protectants against P. truncatus adults. Chlorantraniliprole formulations were applied as solutions at 0.01, 0.1, 1 and 10 ppm, and tested at 20, 25 and 30 °C. Both formulations performed similarly. After 7 days of exposure, the overall mortality provided by both formulations was very low (<17%). Seven days later, mortality was remarkably increased on maize treated with 1 and 10 ppm at 25 and 30 °C for both formulations. The highest mortality was noted in chlorantraniliprole WG, at 10 ppm and 30 °C (98.9%), followed by chlorantraniliprole SC (96.1%), at the same dose and temperature. WG formulation was more effective at 10 ppm and 25 °C (92.8%) than SC formulation (89.4%). No progeny production was noted on maize treated with the WG formulation at 20 and 30 °C. The SC formulation caused complete offspring suppression at 10 ppm at all three tested temperatures. The results of the present work indicate that chlorantraniliprole is an effective compound with a high insecticidal activity against T. truncatus on stored maize that depends on temperature, dose and exposure interval. The fact that chlorantraniliprole is a broad-spectrum insecticide, exhibiting low toxicity to mammals and beneficial arthropods, could be a valuable management tool in storage facilities. Full article

The Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) are worldwide spread and notorious organisms of numerous stored-products. Both species are dangerous for bagged commodities as penetrators and invaders. The aim of the current study was to examine the efficacy of thiamethoxam, pirimiphos-methyl, alpha-cypermethrin, and deltamethrin, against E. kuehniella and T. confusum larvae, on different types of storage bag materials, i.e., woven propylene, biaxially oriented polypropylene and kraft paper through a (quasi)-binomial modeling approach. The type of the tested storage bag material did not affect the mortality rates of both species when treated with the tested insecticides. Thiamethoxam and pirimiphos-methyl showed statistically significant higher mortality rates on E. kuehniella and T. confusum (beta coefficient = 0.141; p-value < 0.05) compared to alpha-cypermethrin and deltamethrin. In addition, T. confusum exhibited significantly higher mortality rate in comparison to E. kuehniella. Our results also showed that the tested doses and surface treatments had a significant effect on the mortality E. kuehniella and T. confusum larvae. Significantly higher mortality rates were recorded when larvae were exposed on bag materials having both surfaces treated or on the single treated surface than when they were exposed on the untreated surface. Our findings can be useful towards an effective management strategy against stored-product insect pests. Full article

This paper reports beetle pests common to flourmills targeted during a series of trapping studies over a two-year period in flourmill 1 and a one year period in flourmill 2. Objectives were (1) use pheromone-baited traps to detect T. castaneum (Herbst) and other pest species present for their distribution over space and time, (2) monitor T. castaneum activity before and after fumigations to assess efficacy of the treatment, and (3) correlate counts of T. castaneum via trap capture against direct T. castaneum counts from samples of the milled flour to assess the value of trap data to estimate relative size of the pest population. Traps were deployed in two different flourmills over two consecutive years. T. castaneum was the most commonly trapped beetle during both years in mill 1. In mill 2, Typhaea stercorea (L.) and Cryptolestes ferrugineus (Stephens) were both captured in higher numbers than T. castaneum. In mill 1, trap capture was higher overall during Year 2 for most of the species compared with capture during Year 1, likely due to a dust cover modification made for the pitfall trap used in Year 2. Trap capture was also evaluated by location within the mills and a significant difference was found in the capture of T. stercorea during both years in mill 1. T. castaneum captures were significantly reduced following most fumigations, which used methyl bromide in milling areas and phosphine in bulk-stored finished flour. However, in most cases trap catches showed that beetle populations were not eliminated. Trap captures after fumigation suggest either that the fumigations were not entirely effective, or that full grown adult beetles were entering the mill soon after fumigation. When captures of T. castaneum from traps in two spaces of mill 1 during Year 2 were compared with counts of beetles from samples of siftings collected in the finished flour, the correlation coefficients were nearly significant for both sets of traps. Full article

At a time when there is much talk of reducing pesticide use and the implementation of integrated pest management, mainly in fields and glass-houses, it is appropriate to consider how cereals in storage are handled and what measures are taken to protect them against insects and other pests. For decades, the use of various synthetic pesticides has been the basis for the proper and long-term storage of cereals, primarily free of insects and mites, but also fungi and their mycotoxins and rodents. However, due to the registered negative effects of synthetic pesticides, such as dichloro-diphenyl-trihloroethane (DDT) or methyl bromide, on human health and the environment, and the appearance of resistance to, e.g., malathion, researchers have been looking for new acceptable control measures. Due to the proven and published non-acceptable data regarding synthetic pesticide effects, a combination of physical, mechanical, and biological measures with the minimal use of synthetic pesticides, under the name of integrated pest management, have been promoted. These combinations include high and low temperatures; the removal of dockages; and the application of pheromones, diatomaceous earth, and natural compounds from various plants, as well as inert gases, predators, and parasites. A ban of any synthetic pesticide usage is currently being considered, which emphasizes the fact that protection should only be performed by measures that do not leave harmful residues. However, the facts show that the application of physical, mechanical, and/or biological measures, besides the fact that they are not necessarily efficient, is very demanding because more knowledge and experience is required, as well as better equipment, greater financial investment, and awareness raising not only for agricultural producers and storage keepers, but also for consumers. In order to use these measures, which are less hazardous to humans and the environment, it is necessary to adapt regulations not only to speed up the registration protocols of low-risk pesticides, but also to prescribe criteria for placing agricultural products on the market, as well as quality standards, i.e., the permitted number of present insects, in addition to their parts in certain types of food. Additionally, we should be aware of control measures for protecting novel food and other non-traditional foods. It is important to continue to combine different protection measures, namely integrated pest management, until all of the other new procedures that must be carried out during the period of storing cereals and other products are clear, in order to ensure the best quality of final products for consumers. Full article

Mating disruption of Cadra cautella (Walk.) (Lepidoptera: Pyralidae) using its sex pheromone components, (Z, E)-9,12-tetradecadienyl acetate (ZETA) and (Z)-9-tetradecadien-1-yl acetate (ZTA), is successful in its population management. In addition, botanical oils have extensively been investigated in stored product pest management, but the effect of synthetic sex pheromones on the mating of C. cautella in the presence of plant volatiles is still unknown. Spinosad is used in food facilities as a contact insecticide but, if C. cautella larvae burrow into food, they may escape from spinosad. Importantly, the impact of spinosad on burrowing ability of C. cautella remains unknown. Therefore, the objectives of this study were to determine the effects of sex pheromone components ZETA and ZTA in the presence of botanical oils on the mating of C. cautella and the burrowing ability of C. cautella larvae in different types of flour treated with spinosad. In the first study, male and female moths were introduced into the cubicle having botanical oils and pheromone components. The mating status of female moths and male moth attraction to the trap was determined. The control experiments had only the botanical oils or pheromones. In the second study, burrowing ability of C. cautella larvae through different flour types was evaluated over 10 d. The flour was sprayed with spinosad (treatments) or water (controls). The mating success was higher with botanical oils alone but declined with exposure to pheromone either alone or combined with botanical oils. No differences in male attraction to traps were observed in botanical only, pheromone only or pheromone + botanical oil treatments. The burrowing of C. cautella larvae differed with flour type and spinosad altered burrowing ability. Thus, we conclude that the mating and burrowing of C. cautella is influenced by its pheromone and by exposure to botanicals and spinosad. Full article

The red flour beetle, Tribolium castaneum, is an important pest of stored products. We compared an existing standard commercial trap with five experimental trap designs differing from the status quo in shape, surface texture, and in forced air capability provided by fans. We tested the five new traps and a commercial trap with T. castaneum adults with the presence/absence of air flow and the availability of either the pheromone only or both the pheromone and kairomone. Without using the fans and baited with pheromone only, these new trap designs capture beetles three to five times as efficiently as the status quo trap. Use of both pheromone and kairomone doubled the capture efficiency of the status quo trap but did not significantly affect the capture efficiency of the new trap designs, all of which captured significantly more effectively than the status quo trap. Turning on fans for forced ventilation significantly improved trap efficiency of the more effective of the newer traps compared to monitoring with both pheromone and kairomone but no fan. This study provides new insights into factors affecting trap efficiency for monitoring of T. castaneum in grain storage facilities, and suggests ways in which existing traps might be improved. Full article

A series of laboratory and field experiments were performed to assess the responses of Tribolium castaneum (Herbst) and other stored-product beetles to pheromone-baited traps and trap components. A commercial Tribolium pitfall trap called the Flit-Trak M², the predecessor to the Dome trap, was superior in both laboratory and field experiments over the other floor trap designs assessed at capturing walking T. castaneum. In field experiments, Typhaea stercorea (L.) and Ahasverus advena (Stephens) both preferred a sticky trap to the pitfall trap. Although the covered trap is effective at capturing several other species of stored product beetles, the synthetic Tribolium aggregation pheromone lure is critical for the pitfall trap’s efficacy for T. castaneum. Although the food-based trapping oil used in the pitfall trap was not found to be attractive to T. castaneum when assayed alone, it had value as an enhancer of the pheromone bait when the two were used together in the trap. A dust cover modification made to go over the pitfall trap was effective in protecting the trap from dust, although the trap was still vulnerable to dust contamination from sanitation techniques that used compressed air to blow down the mill floors. Capture of T. castaneum in the modified trap performed as well as the standard trap design in a non-dusty area of a flour mill, and was significantly superior over the standard trap in a dusty area. T. castaneum responded in flight outside a flourmill preferentially to multiple funnel traps with pheromone lures compared to traps without pheromone. Full article

The lesser grain borer, Rhyzopertha dominica, and the rust red flour beetle, Tribolium castaneum, are two major beetle pests commonly found infesting stored products worldwide. Both species can cause severe economic damage and their management is complicated by their potential to develop resistance to several of the limited chemical options available. However, pest management strategies can be improved by understanding the ecology of the pest insect. To determine the spatiotemporal activity of R. dominica and T. castaneum, we conducted a trapping study over two years in a temperate region of south-eastern Australia, with traps located near grain storages and fields. We captured higher numbers of R. dominica than T. castaneum, and both species were more prevalent in traps located close to grain storages. Similar and consistent seasonal patterns were displayed by both species with activity ceasing during the winter (June–August) months. We found linear correlations between maximum daily temperatures and trap catches, and minimum threshold temperatures for flight activity were 14.5 °C and 15.6 °C for R. dominica and T. castaneum, respectively. The results are discussed in relation to the ecology of these pests along with their implications for pest management. Full article

The Indian meal moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is controlled by commercial mating disruption dispensers using passive release to emit high concentrations (relative to females or monitoring lures) of their principal sex pheromone component, (9Z,12E)-tetradecadienyl acetate. Since P. interpunctella is sexually active throughout the scotophase, an assay system was developed to determine the importance of direct interaction of the male with the dispenser, and whether exposure to mating disruption early in the night is sufficient to suppress mating throughout the night. Exposure to mating disruption dispensers in the mating assay chamber for the first two hours of a 10-h scotophase significantly reduced mating when females were introduced four hours later. Mating was also reduced to a lesser degree in a concentration-dependent manner based solely on re-emission of pheromone, and when males were exposed outside the mating assay chamber. These results indicate that the commercial mating disruption dispensers can suppress mating throughout the night based on interaction with the dispenser early in the night. Desensitization resulting from attraction to a high-concentration pheromone source is important to this suppression, but other factors such as re-emission from the environment may also have a role. These observations imply a non-competitive mechanism for P. interpunctella with the product studied, and suggest that effectiveness of the mating disruption dispenser might be augmented by using them in conjunction with another formulation such as an aerosol or micro-encapsulated product. Full article

Necrobia rufipes (De Geer) (Coleoptera: Cleridae), also known as the red-legged ham beetle, is a newly emerging pest of pet food stores, causing apprehension among producers worldwide. Concerns about this pest are exacerbated by the lack of information about infestation modalities in pet food, while specific monitoring tools are missing. Considering that adequate pet food packaging could limit N. rufipes infestations, information about the penetration modalities in commonly used pet food packaging is needed. Moreover, the development of appropriate monitoring instruments is urgent to detect pest presence early and to reduce chemical treatments for its control. In this paper, the adults’ and larvae’s ability to enter into pet food packaging was evaluated. Furthermore, to develop monitoring traps, behavioral bioassays were done: (1) testing two different commercial adhesive surfaces, one generally used in mouse glue traps (MG), and the other used in cockroach glue traps (CG), to evaluate their different abilities in avoiding insects’ escape; (2) screening different molecules, typical of the substrates attacked by N. rufipes, as candidate food attractants for this pest: methyl cyclopentenolone (MCP), squalene (SQ), and stearic acid (SA). The results show that N. rufipes adults and larvae enter into packaging through the air vent valves on the bottom, suggesting that a way to improve the packaging to prevent insect infestation would be to modify these points of weakness. Laboratory tests show that the different bioassayed glues have strong differences in the ability to retain the caught insects, with MG being more effective than CG. The behavioral bioassay indicated that MCP and SQ attract N. rufipes adults in olfactometer. Finally, the results of dual-choice arena bioassays show that among the candidate attractant tested, a mixture of pet food (PF) and MCP elicited the strongest attraction in N. rufipes adults. These results encourage further experiments with the use of an MG adhesive trap loaded with a mixture of PF+MCP to test the effectiveness of such a tool for monitoring N.rufipes in pet food industries and warehouses. Full article

Diatomaceous earth (DE) has long been known as a potential protectant for stored cereals against various stored product insects. Despite favorable effect for the environment and human health, DE has some negative side effects on the treated commodity. In order to minimize negative response and to improve its efficacy, this paper represents a study of developed natural formulation based on DE SilicoSec^® enhanced with botanicals (essential oil lavender, corn oil, and bay leaves dust) and silica gel. The activity of formulation (labeled as N Form) was tested against Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Tribolium castaneum (Herbst) in seed wheat and barley under controlled conditions. As a reference comparative value, DE SilicoSec^® was used. N Form showed higher efficacy than DE, especially in barley at the lowest concentration, inducing higher mortality of all three insect species. The highest average progeny inhibition was recorded in R. dominica population both in seed wheat and barley with 94.9% and 96.3% of inhibition, respectively, followed with S. oryzae and T. castaneum inhibition of 90.6% and 86.1%, respectively, in wheat and 94.9% and 89.7%, respectively, in barley. Results indicate that the developed natural formulation N Form enhanced the activity of DE SilicoSec^® using lower amount of DE dust and that it could be successfully implemented for storage of cereals as alternatives to chemical pesticides for stored product insect control. Full article

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is an important pest of stored products. Insecticidal treatment is a common practice for the control of this notorious insect pest. Most studies are focused on the immediate and/or delayed mortality effects, while there are no data on the effects of insecticides on the population fitness. This study deals with the effect of chlorfenapyr on T. castaneum, investigating the cost of exposure of different developmental stages on population performance, by using life table statistics and a survival analysis method. For this purpose, eggs, larvae, and parental adult females of T. castaneum were exposed to chlorfenapyr and birth or death rates were calculated daily. The exposure of eggs and larvae to chlorfenapyr was detrimental for T. castaneum and they did not complete development. When parental females were exposed to chlorfenapyr, the progeny survival curve, biological features, as well as the life table parameters did not differ significantly compared to the control treatment. Thus, egg hatching, larval and pupal developmental periods, female and male longevities for the control treatment, and the progeny of the females that were exposed to chlorfenapyr were 4.66 and 4.76 days, 25.85 and 25.71 days, 5.00 and 5.26 days, 87.33 and 104.22 days, and 76.87 and 91.87 days, respectively. In addition, the mean values of the net reproductive rate, the intrinsic rate of increase, the mean generation time and the doubling time for the control treatment and the progeny of the parental females which were exposed to chlorfenapyr were 14.3 and 9.3 females/female, 0.038 and 0.028 females/female/day, 1.039 and 1.029, 70.0 and 76.9 days, and 18.5 and 24.9 days, respectively. We expect these results to have bearing on the management of T. castaneum, since the repeatedly insecticidal applications could be reduced in storage facilities. Full article

This study explores the influence of rosemary, Rosmarinus officinalis (L.) essential oil (EO) on the biochemical (acetylcholinesterase, catalase, and glutathione S-transferase), physiological (oxygen consumption), and behavioral (open field test, repellency) parameters of an important stored product insect: cowpea weevil, Callosobruchus maculatus (F.). R. officinalis EO exhibited effective insecticidal action against C. maculatus even at relatively low concentrations. LC₅₀ = 15.69 μL/L air, and was highly repellent at concentrations equal to or above LC₂₅. Statistically significant inhibition in locomotor activity occurred only after the acute exposure to the EO at LC_12.5 and LC₂₅. The oxygen consumption test showed metabolism increase only at LC₅₀. An increase in activity was observed in the case of all three enzymes examined. The presented data provides a potentially valuable resource in designing more environmentally friendly and safer insecticide agents. Full article

The granary weevil, Sitophilus granarius Linnaeus 1875, is a primary pest of stored grains worldwide. Feeding damage and progeny production of S. granarius was estimated to identify the levels of resistance of the insect on different durum wheat cultivars. Insect attack on four different durum wheat cultivars was investigated over a period of 20 weeks. Durum wheats were artificially infected with 20 individuals of S. granarius. Every two weeks the sample weight, hectoliter weight, moisture and the number of live weevils, including their number of progenies, were recorded. Overall findings revealed different levels of resistance of different durum wheat cultivars to S. granarius infestation. The Primadur cultivar had the highest resistance, followed by the Marco Aurelio and Cesare cultivars followed finally by the Tito Flavio cultivar which was highly susceptible to S. granarius. For all cultivars, apart from Primadur, S. granarius metabolism increased humidity and temperature, leading to grain degradation and resulting in the potential complete loss of market value if under field conditions. Evidently, durum wheat characteristics affect the life cycle of S. granarius, primarily their progeny, and thus the damage they undertake to the wheat itself. These findings are important because they enable the strategic selection of wheat cultivars that can be stored for a longer time period, while more sensitive wheat cultivars can be selected for shorter storage time and thus faster delivery to market. Full article

This study investigated the effects of diallyl trisulfide (DAT), an active substance from garlic essential oil, on the metabolism of the main energy substances of pre- and postmating males of Sitotroga cerealella. Males at 12 h postemergence were fumigated with DAT at a concentration (LC₁₀ = 0.010 µL/L) in a glass jar for 7 h. The main energy metabolites from pre- and postmating males were determined, including protein, triglyceride, glycogen, total soluble sugar, trehalose, and trehalase. The contents of total protein and total soluble sugar and the trehalase activity of premating males were significantly increased following DAT treatment, whereas the contents of protein from the accessory gland, triglyceride, glycogen, and trehalose were significantly decreased after treatment. Additionally, after mating, the total protein and soluble sugar contents were significantly increased and the glycogen content was significantly decreased in the treatment group relative to the levels in controls, but there was no significant difference observed in triglyceride, accessory gland proteins, trehalose content, or trehalase activity between the treatment and control groups. Furthermore, the changes in the main energy substances between pre- and postmating in males after the DAT treatment (∆DAT) were smaller than those in the control group (∆CK). This result indicated that DAT can accelerate the rate of metabolism in males at LC₁₀, leading to the accumulation of greater levels of total soluble sugar to support life activities and to the increased synthesis of proteins to resist an adverse environment. Full article

The khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is one of the most destructive insect species of stored food worldwide and is subjected to strict phytosanitary legislations. In the present study, we evaluated the egg hatching and larval mortality of T. granarium on concrete surfaces treated with six insecticides (i.e., α-cypermethrin, chlorfenapyr, deltamethrin, pirimiphos-methyl, pyriproxyfen, and s-methoprene) that are registered in Greece for surface treatment and exhibit a broad spectrum of different modes of action. Furthermore, we investigated the influence of the presence of food on egg hatching and larval mortality. Egg hatchability on treated concrete was higher in tests with the presence of food for all tested insecticides, with the exception of s-methoprene. In contrast, larval mortality was lower in treatments where there was nourishment for all insecticides. No egg hatching was recorded on concrete treated with pirimiphos-methyl where there was no food, while with the addition of food, the egg hatching did not exceeded 26.7% after 6 days of exposure. The highest percentage of hatched eggs was recorded on concrete treated with chlorfenapyr (87.7% with food vs. 76.7% without food), followed by deltamethrin (76.7% with food vs. 63.3% without food), pyriproxyfen (50.0% with food vs. 42.2% without food), and α-cypermethrin (28.9% with food vs. 6.7% without food). In the case of s-methoprene, more eggs were hatched in the absence of food (91.1%) in contrast to in the presence of food (86.7%). Regarding mortality, all larvae were dead after 5 days of exposure on pirimiphos-methyl-treated concrete with food. Furthermore, larvae died faster in treatments without food. For α-cypermethrin, 100% mortality was recorded after 4 days of exposure, while with presence of food, all larvae died after 6 days. Chlorfenapyr caused complete mortality of larvae after 5 days of exposure on concrete without food and after 8 days with food. In the case of deltamethrin, 100% mortality was recorded after 7 days in the absence of food and 8 days in the presence of food. Regarding pyriproxyfen, complete mortality was not recorded when food was present, reaching 94.1% 14 days postexposure. However, after 12 days, all larvae died in treatments without food. Although egg hatching was higher in the case of s-methoprene on concrete without food, larval mortality was 100% after 8 days of exposure. Nevertheless, when there was food, 87.3% of the exposed larvae died after 13 days. Therefore, it becomes evident that sanitation of storage facilities before the application of contact insecticides is a key factor for the successful control of T. granarium in the egg stage. Full article

The red flour beetle Tribolium castaneum is a known pest of various grains and stored-products such as wheat flours; however, T. castaneum feeds on and infests soybean and soy products. For more than 60 years, soy flour has been suggested to be unstable food for Tribolium spp. because it causes larval development failure. However, it remains unknown whether soy flour affects adult beetles. The objective of the present study was to examine the effects of soy flour and its related isoflavones against T. castaneum using an artificial dietary intake assay. Beetles were fed gypsum (a non-digestible compound) mixed with either water (control) or soy flour. Significantly fewer beetles survived after being fed the soy flour treatment. Although the soy isoflavone genistein, a defensive agent and secondary metabolite, decreased the T. castaneum adult survival, it required a long time to have a lethal effect. Therefore, the cytotoxic effects of soy flour, i.e., the rapid biological responses following isoflavone addition, were also examined using a cultured cell line derived from T. castaneum. Both genistin and genistein significantly affected the survival of the cultured cells, although genistein had a stronger lethal effect. This study demonstrated the toxicity of genistein found in soybean against T. castaneum cultured cells within 24 h period. Genistein may be used as an oral toxin biopesticide against T. castaneum. Full article

A study of the biological features and the potential population growth between two laboratory strains of the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) from Greece and Serbia is conducted on cracked barley and cracked white rice. The results show that, at a species level, T. confusum is able to complete development on cracked barley but not on cracked white rice. Therefore, cracked white rice proves to be an unsuitable commodity for T. confusum. Larval development on cracked barley is significantly shorter for the Serbian compared to the Greek strain (37.7 and 49.7 days, respectively), but pupal development does not differ between the two strains (6.2 days for both strains). Additionally, male longevity does not differ between the Greek and Serbian strains (144.4 and 151.4 days, respectively), while female longevity is significantly shorter for the Serbian (151.7 days) compared to the Greek strain (186.6 days). Fecundity does not differ between the two strains (11.3 and 17.7 eggs/female for the Greek and the Serbian strain, respectively), whilst survival is higher for the Serbian strain on both tested commodities. The values of the net reproductive rate, the intrinsic rate of increase and the finite rate of increase on cracked barley are significantly higher for the Serbian (7.27 females/female, 0.025 female/female/day and 1.026, respectively) compared to the Greek strain (2.91 females/female, 0.014 females/female/day and 1.014, respectively). It therefore is expected that different strains of T. confusum may exhibit variable phenology as well as potential population growth. Additionally, we expect our results to have bearing on the management of this species. Full article

Insect survival after exposure to 0 °C for 7 days was examined in laboratory bioassays for control of adults of six major stored-product beetle species, Oryzaephilus surinamensis (L.), the sawtoothed grain beetle, Cryptolestes ferrugineus, (Stephens), the rusty grain beetle, Dermestes maculatus DeGeer, the hide beetle, Sitophilus oryzae (L.), the rice weevil, Tribolium castaneum (Herbst), the red flour beetle, and T. confusum Jacquelin DuVal, the confused flour beetle In this test there were four different acclimation treatments, insects that had been subjected to a pre-acclimation period to 0 °C, a post-acclimation period, both a pre and post-acclimation period, and adults that were not acclimated. Insect survival for all species except S. oryzae was not affected by the exposure to 0 °C, regardless of the acclimation scenario. In contrast, exposure to 0 °C drastically reduced survival of S. oryzae. Moreover, adults that were exposed to the post-acclimation only and un-acclimated adults had lower survival rates than those that had either exposure to pre-acclimation, or to both pre- and post-acclimation. Results of this experiment show that acclimation played a limited role in adult survival of five of the six tested species, and that exposure of adults to 0 °C for 7 d had no effect in survival of these species as well. Full article

In the current study it was investigated the suitability of semolina, cracked wheat and cracked maize as feeding commodities for the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). The pest completed its development on all tested commodities. The developmental time of larvae was lower on cracked wheat (59.6 days) and cracked maize (54.6 days) compared to semolina (72.8 days). The developmental time of pupae did not differ significantly among tested commodities, ranging from 6.2 to 6.6 days. Female and male longevities were 70.9 and 77.1 days, 92.2 and 77.9 days and 177.0 and 183.7 days, when T. castaneum was fed on semolina, cracked wheat and cracked maize, respectively. The highest fecundity (28.7 eggs/female) was recorded when T. castaneum was fed on semolina, followed by cracked wheat (2.7 eggs/female) and cracked maize (1.2 eggs/female). The prolonged adult longevity, which was observed on cracked maize, may be attributed to the absence of the cost of reproduction, due to low fecundity on this commodity. The values of the intrinsic rate of increase were 0.014 and −0.021 females/female/day when it was fed on semolina and cracked wheat, respectively, while no demographic analysis was carried out for cracked maize due to high early larval mortality and low fecundity on this commodity. The net reproductive rate and mean generation time were 6.19 females/female and 127.5 days and 0.16 females/female and 91.9 days, when it was fed on semolina and cracked wheat, respectively. Based on demographic analysis, T. castaneum population growth is favored only on semolina. We expect semolina to act as a suitable commodity for T. castaneum, while cracked wheat and cracked maize allow only its survival by acting as alternative commodities. The estimated demographic parameters of T. castaneum on the tested commodities could be used as a useful tool to predict its population outcome in storage facilities. Full article

Farmers in developing nations encounter high postharvest losses mainly attributable to the lack of modern techniques for threshing, cleaning, grading, and grain storage. Mechanized handling of grain in developing countries is rare, although the technology is effective against insects and pest infestations. The objective was to evaluate the cost-effectiveness of five grain handling techniques that have the ability to reduce postharvest losses from insect infestation. The five methods were metal silo plus all accessories (m. silo + acc.), metal silo only (m. silo), woven polypropylene plus phosphine (w. PP. + Phos.), woven polypropylene only (w. PP.), and Purdue Improved Crop Storage bags only (PICS). The functional unit used was handling 1 kg of maize grain. The cost analysis of each technique was calculated based on equations using a spreadsheet. The annual capital and operational costs of handling using m. silo + acc. or m. silo were very high, unlike the PICS, w. PP. + Phos., or w. PP. The annual capital and operational costs decreased as production scale increased. Food security (due to reduced insects and pest infestations) and financial prospects of farmers can improve when the grain is mechanically handled with m. silo + acc. or m. silo. Full article

Carpophilus dimidiatus (Fabricius, 1792) and Carpophilus pilosellus Motschulsky are two sibling species and economically important storage pests worldwide. The first complete mitochondrial (mt) genomes of both were sequenced using next-generation sequencing. The mt genomes of C. dimidiatus and C. pilosellus are circular, with total lengths of 15,717 bp and 15,686 bp, respectively. Gene order and content for both species are similar to what has been observed in ancestral insects and consist of 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a control region. Comparing the mt genome data of C. dimidiatus and C. pilosellus, they are similar in organization, arrangement patterns, GC contents, transfer RNA (tRNA) secondary structures, and codon usage patterns. Small differences were noted with regards to the nucleotide similarity of coding regions and the control region. This is the first publication of the complete mitochondrial genomes of two sibling species. The mt genome sequences can supplement the nuclear markers of the Carpophilus genus in research species identification, system evolution, and population genetic structure, and also will be valuable molecular marker for further genetic studies. Full article

The Angoumois grain moth, Sitotroga cerealella (Olivier, 1789) (Lepidoptera: Gelechiidae), is primarily a pest of stored products, that feeds inside the grain as larvae inducing significant economic loss in various stored commodities. Our previous studies proved that garlic essential oil and its active substances inhibit oviposition in moths. To further explore the effect on reproductive behavior and accurately interpret the results in terms of effective control of the moth population, moths were treated with diallyl trisulfide (DATS), an active substance of garlic essential oil, at a dose of 0.015 µL/L in air (LC₂₀, sub-lethal concentration). The results showed that fecundity and the proportion of viable eggs significantly decreased when the moths were treated with LC₂₀ DATS. Furthermore, female circadian mating rhythms and calling periodicity changed significantly after treatment. Compared with controls, the peak in mating occurred approximately 1 h earlier on the first day after DATS treatment, while it was significantly later on days 2 and 3. Moreover, mating frequency declined in presence of DATS compared with the controls. The percentage of females engaging in calling behavior decreased significantly with time, to less than 50%, 2 days after treatment, while a high calling percentage (>80%) was recorded for control moths on all 4 days. In addition, DATS had an inhibitory effect on the mating duration of S. cerealella. Moreover, a significant reduction was observed in the amount of sex pheromones extracted 8 h and 9 h after treatment. Our findings suggested that DATS has the potential to manipulate the moth population at LC₂₀ and would be an efficient alternative to synthetic insecticides for the control of pests having low toxicity to non-target organisms and ecosystems. Full article