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Tribolium castaneum has a long history as a model species in many distinct subject areas, but improved connections among the genetics, genomics, behavioral, ecological, and pest management fields are needed to fully realize this species' potential as a model. Tribolium castaneum was the first beetle whose genome was sequenced, and a new genome assembly and enhanced annotation, combined with readily available genomic research tools, have facilitated its increased use in a wide range of functional genomics research. Research into T. castaneum's sensory systems, response to pheromones and kairomones, and patterns of movement and landscape utilization has improved our understanding of behavioral and ecological processes. Tribolium castaneum has also been a model in the development of pest monitoring and management tactics, including evaluation of insecticide resistance mechanisms. Application of functional genomics approaches to behavioral, ecological, and pest management research is in its infancy but offers a powerful tool that can link mechanism with function and facilitate exploitation of these relationships to better manage this important food pest. Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

In the present work, a series of tests were performed to examine the effect of previously captured adults in floor traps, on the captures of Τrogoderma granarium Everts and T. variabile Ballion, in single species releases. In a first series of tests, a single trap with kairomone oil and dead adults of single or both species was placed in a plastic container, which was used as the release arena. Subsequently, adults of both species were separately released in the arena, and the adult capture was recorded 24 h later. In a second series of trials, two traps were placed in the same arena, containing different numbers of prior seeded adults, and adult capture was similarly recorded. For T. granarium, in all cases, more adults were found inside the trap than under the trap or on the trap walls. In contrast, for T. variabile, most adults were recorded on the trap walls. In general, T. variabile had a stronger response to the traps than T. granarium. This work illustrates that previous captures of either species do not negatively affect captures of new live adults and may tend to enhance captures in some cases. This has important implications for the use of traps for the biosureveillance of these two important dermestid species.

Trogoderma granarium Everts (Coleoptera: Dermestidae) is one of the most important quarantine pests of stored grains. Control of this insect species can be achieved through a gaseous insecticide, phosphine. Many studies focus on the effect of phosphine on different developmental stages of insects, with most of them highlighting eggs as the most tolerant stage. Our data showed that 2-d-old eggs of T. granarium are more susceptible than 1-d-old eggs. Faster hatching was observed in eggs exposed to phosphine for 2 d compared to controls and the result was more pronounced for 1-d-old than 2-d-old eggs. In contrast to the 2-d exposure, hatching rates of eggs exposed to 4 and 6 d were notably reduced, while there was a delay in egg hatching compared to controls. Moreover, larval development from untreated eggs was faster than the larvae from treated eggs, regardless of the exposure time. These dissimilar patters in larval growth may suggest certain delayed effects of phosphine fumigation. The results of the present work can be further utilized for the development of phosphine-based quarantine and pre-shipment treatments for the control of T. granarium.

In this study, we evaluated the susceptibility of four different sorghum varieties to infestation by the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), as compared with wheat, which served as a ‘control’ commodity. In population growth assays, there was preference for population development on wheat compared to the different sorghum varieties. In contrast, there were no significant differences in total population development among the four varieties of sorghum. However, the proportion of immature stages (larvae, pupae) in relation to the adult stage varied significantly among the different varieties. Moreover, significant differences were noted among the commodities tested regarding the final weight decrease, as well as the amount of frass and kernel damage. Our study clearly demonstrates noticeable differences in the susceptibility of the varieties to T. granarium infestation. These results show that this species can develop on different varieties of sorghum, and variety selection should be further considered in a host-plant resistance-based management program for T. granarium.

We evaluated, under controlled laboratory conditions, the insecticidal activity of polydimethylsiloxane (PDMS) for the control of the house mosquito, Culex pipiens. In a first series of bioassays, we tested the residual effect of different PDMS doses to control 3rd instar larvae. The label dose caused high mortality rates (>80%) even after 50 days from the initial application. Mortality levels at half the label dose were significantly higher compared to control, during the entire experimental period following a gradual decrease over time. Similar trends were observed when the 1/4 and the 1/8 of the label dose were applied with a much steeper decrease at long time intervals since the initial application especially for the lowest dose. However, after the 10th day of the bioassays and until the end of the experiments, mortality rates in the case of the label dose were higher compared to all other doses after the initial 10 days post application. Conversely, the insecticidal efficacy of PDMS against pupae was generally lower in comparison with larvae. Indeed, 10 days after the application, mortality was notably reduced, regardless of the dose rate tested. In a second series of bioassays, we assessed the efficacy of short exposures of different instars of larvae and nymphs to registered formulation and label dose. Mortality was well over 95% for 2nd instar larvae at exposure intervals ranging from 1 to 4 days. Significant mortality was recorded to 3rd instar larvae even at 15 min of exposure. Exposures longer than 30 min caused high mortality rates to 3rd instar larvae. Similar results were also recorded in pupae. Finally, in a third series of bioassays, the efficacy of PDMS in egg hatch was tested. Egg hatch was completely suppressed in the treated substrate (all egg rafts were “sinking” at the bottom of the test cups). Moreover, there was no oviposition in the case of the application of the label dose, while some egg rafts were recorded at one-eighth of the label dose. In both cases, it was recorded that PDMS acts as an oviposition deterrent. Τhe results of this study show that PDMS is effective in a wide range of conditions and application scenarios.

Phosphine is the most commonly used gas for fumigation for durable commodities globally, but there is still inadequate information regarding its efficacy in conjunction with proper concentration monitoring. In a series of bioassays, insect mortality after specific exposure intervals to phosphine in selected species was examined, as well as the appearance of the so called "sweet spot". The species that were tested were: Oryzaephilus surinamensis (L.), Tribolium castaneum (Herbst), Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) with populations that had different levels of phosphine resistance. Evaluation was conducted by using the Phosphine Tolerance Test (PTT), with exposure of the adult stage for 15, 30, 60, 90, 150 and 300 min at 3000 ppm. At the end of these intervals (separate bioassays for each time interval), the insects were transferred to Petri dishes, in which recovery was recorded at different time intervals (2 h, 1, 2 and 7 days). The majority of susceptible populations of all species were instantly immobilized even in the shortest exposure period (15 min), in contrast with resistant populations that were active even after 300 min. After exposure to phosphine, populations and exposure time affected mortality of susceptible populations, whereas resistant populations recovered regardless of species and exposure time. Additional bioassays at the concentrations of 500, 1000, 2000 and 3000 ppm for 1, 3, 5, 20, 30 and 40 h showed the presence of the "sweet spot", i.e., decrease of mortality with the increase of concentration. In fact, for most of the tested species, the "sweet spot" appeared in 1000 and 2000 ppm at a 5-h exposure time, regardless of the level of resistance to phosphine. This observation is particularly important both in terms of the assessment of resistance and in the context of non-linear recovery at elevated concentrations, indicating the occurrence of strong hormetic reversals in phosphine efficacy.

A series of tests was performed to examine the development ability of Trogoderma granarium Everts on six different sorghum milling fractions: bran, shorts, coarse grits, fine grits, red dogs, and flour. In the first bioassay, 20 adults and 20 g of each fraction were placed in vials of 60 ml at 30°C and 60% relative humidity for a period of 65 d. In the second part of the experiment, a neonate larva (1-d old) was placed in vials with 1 g of each fraction and exposed at 25, 30, and 32°C until adult emergence. Significantly more live larvae were found in bran compared with flour and to the two grain controls (soft wheat and whole wheat flour), where most dead adults were recorded. The increase in temperature reduced both the time to adult emergence and larval mortality before the appearance of the first adult. Developmental times ranged between 25.5 and 37.5 d, and 23.2 and 29.0 d for 30 and 32°C, respectively. At 25°C, larvae in the milling fractions did not reach 100% adult emergence even after almost 3 mo. However, the first adult appeared in the shorts fraction at all temperatures tested. Our results show that all sorghum milling fractions support the development of T. granarium and that the optimal temperatures for growth and development are 30 and 32°C. These results also have important implications for phytosanitary regulations and international trade, given the quarantine restrictions on this insect.

BACKGROUND Phosphine-susceptible or resistant populations of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) adults were exposed to 0 (control), 1000 and 3000 ppm of phosphine for 15 or 90 min, to estimate behavioral and mobility responses after exposure to phosphine. Knockdown of the exposed individuals after exposure was recorded visually. The total distance moved and velocity of movement were assessed immediately after exposure to phosphine, 2 or 24 h later using a camera coupled with automated video tracking software (i.e. Ethovision®). RESULTS For both species tested, the highest percentage of dead adults was noted at the highest concentration (3000 ppm) for both exposure times. For T. castaneum, total distance moved and velocity decreased as the concentration increased for the susceptible population, whereas there was significant variation among individuals in the resistant population. For R. dominica, the distance moved was reduced at the highest concentrations. Individuals of R. dominica moved less than those of T. castaneum and there were significant differences in mobility between susceptible and resistant populations for both species tested. Recovery was much faster in the case of the resistant populations. CONCLUSIONS Changes in movement parameters can be further exploited in assessing the efficacy of different management tactics, such as trapping and sampling. Automated video tracking systems such as Ethovision® can be used to track and record insect behavioral response, providing a more objective measure of insecticide efficacy than visual categorizations. These data shed light on insect mobility and behavioral responses to fumigation treatments in relation to resistance. © 2020 Society of Chemical Industry.

The Mediterranean basin thrives in native plant species are able to produce numerous derivatives that can be used for insect pest control. This article provides an up-to-date overview of the most important native plant species commonly found in this region that have a certain insecticidal value in vegetable crops. Regarding the insecticidal activity of extracts from selected native species, results from both laboratory and field experiments will be also presented to highlight the potential of the latter as alternatives to synthetic insecticides. Considering the great diversity in ingredients among the various plant species, it is essential to record and describe the chemical composition of these species, in conjunction with their insecticidal activity against the main insect pests of vegetable crops. The review concludes in underlining the critical points for increasing the effectiveness and consequently the practical use of natural insecticides in crop protection. Moreover, emphasis is given in understanding the importance of the production of standardized and stable natural resource-based insecticides through the development of suitable formulations, such as capsule suspension that protects the active ingredients from environmental degradation and improves their residual activity.

Background The insecticidal efficacy of selected mosquito larvicides [teflubenzuron, S-methoprene, diflubenzuron, temephos, Bacillus thuringiensis var. israelensis (Bti) and polydimethylsiloxane (PDMS)], applied alone or in combination, against two Culex pipiens biotypes, Cx. p. pipiens and Cx. p. molestus, was compared under laboratory and semi-field conditions. Registered larvicides were evaluated at the label dose, whereas those not registered for mosquito control were tested at the label dose per area, i.e. as plant protection products. Teflubenzuron and temephos were also evaluated at half the label dose, alone or in combination with a non-ionic surfactant. Larval mortality and adult emergence were assessed after 1, 3, 5, 7, 9, 11, 16 and 20 days of exposure. Results In all cases, PDMS showed complete (100%) larval control after 3 days of exposure against both biotypes. With temephos, all larvae were dead after 1 day of exposure, even at half the label dose. For teflubenzuron, mortality reached 100% at the end of the bioassays and adult emergence was avoided completely, whereas for diflubenzuron, mortality was close to 100% at the end of the trials. By contrast, in S-methoprene-treated water, control was below the 90% mortality threshold for both biotypes. In semi-field trails, in all treatments with Bti, all larvae of both biotypes were dead after 1 day of exposure. Conclusions Based on our data, and with the exception of S-methoprene, the larvicides tested remained below the threshold for effective treatment against larvae of Cx. p. pipiens and Cx. p. molestus for the entire duration of the study. Most of the larvicides tested showed high levels of efficacy against Cx. p. pipiens and Cx. p. molestus larvae in laboratory and semi-field bioassays. © 2020 Society of Chemical Industry.

Insect meal is a new agricultural commodity that will be produced in huge quantities in the near future and will be treated as all traditional agricultural commodities, i.e., insects will be harvested, processed, transported and stored. As most agricultural commodities, insect meals may be prone to insect infestations during their “post-harvest stages.” However, no information is available at the moment on the susceptibility of insect meals to stored-product insect infestations. The objective of the present study was to evaluate the susceptibility of Tenebrio molitor larvae-meal to insect infestations during storage. Specifically, we investigated the population growth of major stored-product insects, i.e., T. molitor, Tribolium confusum, Alphitobius diaperinus and Trogoderma granarium on T. molitor larvae-meal, as well as on T. molitor meal-based substrates with different percentages of wheat bran (0, 25, 50, 75, 90, 95 and 100%). Our results show that T. molitor and T. confusum can infest 100% T. molitor meal and develop significant populations on this substrate. However, the speed of growth of both species in 100% T. molitor meal was considerably lower compared to the substrates that contained also wheat bran. In contrast, A. diaperinus and T. granarium did not grow at all on 100% T. molitor meal and both exhibited poor growth on the substrate containing 75% insect meal. In general, our results show the susceptibility of T. molitor larvae meal, as well as T. molitor meal-based substrates with different percentages of wheat bran, to infestations by major stored-product insects. To our knowledge, this is the first study on the susceptibility of insect meals to insect infestations.

The tetraploid domesticated emmer wheat, Triticum turgidum L. subsp. dicoccon, expresses α-amylase protein inhibitors of varying sizes and assemblies, i.e. dimers and heterotetramers of polypeptide chains of about 12–15 kDa. Although genetic studies have shown the presence of coding sequences for monomeric inhibitors in tetraploid wheat and whole-seeds proteomic studies have indicated their expression, until now there has been no isolation nor characterization of such proteins. In this study, for the first time, an inhibitory protein of human salivary and Tenebrio molitor, Tribolium castaneum, Sitophilus oryzae, and Ephestia kuehniella α-amylase (EC 3.2.1.1), was isolated from whole flour extracts of a tetraploid wheat and its sequence was determined by MS analyses. The inhibitor acts more strongly against coleopteran α-amylases than against those from E. kuheniella and human saliva. The inhibitory characteristics along with the putative sequence determination reported in the present study, allows for further evaluation towards its utilization as a post-harvest protection strategy against insect infestations.

Interspecific competition between agricultural pests may affect the species that can establish, and may also affect food production. Prostephanus truncatus (Horn), the larger grain borer, is endemic to Central America, but invaded Africa with disastrous consequences for maize production. Its main competitor is Sitophilus zeamais Motschulsky, the maize weevil, which is cosmopolitan. These insects co-occur in many regions of the world and both are threats to maize. However, the impact of competition between these two species is not well-understood, nor is its effect on grain quality or potential to limit P. truncatus invasion in new areas. The aims of our study were to evaluate the outcome of interspecific competition between P. truncatus and S. zeamais at four different temperatures on a fixed quantity of grain, and determine effects on progeny production, grain damage, and mold growth. We found that coexistence may be possible at a range of 25–30°C, but mixed colonies experienced a direct competitive cost compared to single-species colonies. Prostephanus truncatus performed better at warmer temperatures, while S. zeamais favored cooler temperatures. The majority of grain damage was the result of P. truncatus activity as opposed to S. zeamais. Finally, mold growth was greater where both species were present, and species of mold that produce aflatoxin were identified. Although there are an increasing number of areas where both of these species occur, our results suggest P. truncatus will be capable of destroying much more maize in a shorter period compared to S. zeamais at temperatures greater than 25°C.

In the present study, we investigated the residual insecticidal efficacy of a commercial cypermethrin formulation applied on grains (wheat, maize) against adults of Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.) and Prostephanus truncatus (Horn) in laboratory bioassays. The insecticide was applied in its label dose on the grains and a bioassay was initiated at the day of application and every month for four consecutive months (5 bioassays in total). In each bioassay, adult mortality levels were determined after exposure for 7, 14 and 21 d. After the final evaluation, all beetles (dead and alive) were removed and the number of offspring was assessed after an additional interval of 65 d. Based on our results, the application of the tested cypermethrin formulation as a grain protectant provided long-term protection against R. dominica and P. truncatus adults, as in most cases complete control was achieved for these two species, even after four months of storage of the treated commodities. In the case of S. oryzae and O. surinamensis, adult mortality did not reach 100% in any of the cases, moreover, a gradual decline of mortality levels was recorded over the 4-month period of storage. Finally, for S. oryzae and P. truncatus progeny production was notably suppressed by cypermethrin. Results show that the cypermethrin formulation tested could be a valuable tool for stored grain protection, however, factors such as the target species and the storage interval should be taken into consideration.

The insecticidal effect of an aerosol formulation that contained a 100: 1 mixture of pyrethrin and methoprene (by volume), was evaluated for control of nymphs of four stored-product psocid species, Liposcelis bostrychophila, L. decolor, L. entomophila and L. paeta. The aerosol was applied at two particle sizes, 2 and 16 μm. The application time of the aerosols was 0 (untreated controls, no aerosol), 5, 10, 20 and 30 min. Nymphs were examined at 5 days post-treatment. The aerosol was effective on all species tested, with mortality of 100% after 5–20 min, depending on the species. There was a strong interaction between the application time and the particle size. In all cases, the application of the aerosol at 16 μm was more effective than 2 μm for all species. Moreover, the application at 16 μm required less time to reach 100% mortality, suggesting that this particle size may provide a more cost-effective application, as it requires less formulation and a considerably shorter application time. Our results provide the first series of data for the application of aerosols at different particle sizes against stored-product psocids and could be used as a guide for improved management of psocids.

Several pyrrole derivatives exhibit insecticidal activity and can be effective as grain protectants. In the present study, we evaluate the insecticidal efficacy of six novel pyrrole derivatives, namely methyl 3-(methylthio)-4,6-dioxo-5-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole-1 carboxylate (compound syn) (2a-syn), methyl 3-(methylthio)-4,6-dioxo-5-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole-1-carboxylate (compound anti) (2a-anti), methyl 3-(benzylthio)-4,6-dioxo-5-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole-1-carboxylate (compound syn) (2f-syn), methyl 3-(benzylthio)-4,6-dioxo-5-phenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrrole-1-carboxylate (compound anti) (2f-anti), methyl 3-(butylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1-carboxylate (3e), and methyl 2-benzyl-3-(methylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-1-carboxylate (0665), against four important species infesting stored products, the rice weevil, Sitophilus oryzae (Coleoptera: Curculionidae), the lesser grain borer, Rhyzopertha dominica (Coleoptera: Bostrychidae), the confused flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae), and the Mediterranean flour moth, Ephestia kuehniella (Lepidoptera: Pyralidae). The six pyrrole derivatives were evaluated on wheat at different doses (0.1, 1, and 10 ppm) and exposure intervals (7, 14, and 21 days). For S. oryzae adults, the highest mortality was recorded at 10 ppm of 2a-syn (36.7%) followed by 2f-syn (32.2%) and 2f-anti (27.8%) after 21 days of exposure. Regarding progeny production, the application of the six pyrrole derivatives significantly reduced offspring emergence if compared with the controls. After 21 days, mortality of R. dominica reached 50% testing 10 ppm of 2f-syn, followed by 2a-syn (46.7%), 2f-anti (41.1%), and 2a-anti (33.3%), while for 3e and 0665, mortality remained low, not exceeding 17.8%. Mortality of T. confusum adults was very low, ranging from 0 to 16.7% after 21 days of exposure. Progeny production was low (

Thaumetopoea pityocampa (Denis and Schiffermüller) is a severe defoliator of various species of Pinus and Cedrus, while the urticanting hairs produced by its larvae cause public health problems for humans and pets. In the present study, we report results of trials (from summer 2015 until winter 2017) of mating disruption for management of T. pityocampa in different areas of Italy and Greece. Overall, the total number of male moths captured in mating disruption-treated plots over each season (70) was significantly lower than the respective number in untreated plots (780). The total number of winter nests was likewise significantly less in the mating disruption plots (13) compared with control plots (147). Our results indicate that mating disruption can be an important tool for judicious, insecticide-free control of T. pityocampa in urban, suburban, and recreational areas, where many alternative control measures are not available.

Stored-product insects can transfer a wide range of serious pathogens involved in human health. The close contact of these insects with the food production chain makes these species extremely dangerous as carriers of severe infections. In addition, pathogenic bacteria, such as members of Enterococcus, are often resistant to antibiotics commonly used for human therapy. Herein we identified, using Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS), Enterococcus and coliform species isolated from 17 strains of different insect species associated with durable stored products. The antibiotic susceptibility of the isolated strains was also evaluated. MALDI-TOF MS revealed mainly the presence of Enterococcus (E. faecium, E. phoeniculicola and E. casseliflavus) and Enterobacter (Eb. cloacae and Eb. asburiae). E. casseliflavus was resistant to all antibiotics tested, while E. faecium and E. phoeniculicola were resistant to sulphonamides. Among E. faecium isolates, approx. 20% were found to be resistant to tetracycline, while Eb. cloacae and Eb. asburiae showed resistance to erythromycin. The current series of data clearly indicates that certain bacteria of the genera Enterococcus and Enterobacter are very common in stored-product insects, and, under certain circumstances, may seriously endanger public health, through potential introduction of antibiotic resistance.

The use of phosphine has been effective against a wide range of stored-product pests in different types of commodities and facilities. However, its continuous and improper use has led to resistance development in -several major insect species. Although phosphine resistance has been reported from many countries across the globe, reports from Europe have been very limited. In the present study, we determined phosphine resistance in insect populations that had been collected from a range of storages across Greece, using two different diagnostic protocols. Apart from the traditional Food and Agriculture Organization (FAO) protocol, a field test kit (known as the Detia Degesch Tolerance Test Kit, DDTTPK) was utilized, for “same day” determination of the resistance status of field collected insects. In total, 53 populations belonging to Rhyzopertha dominica, Sitophilus oryzae, Sitophilus granarius, Cryptolestes ferrugineus, Tribolium confusum, Tribolium castaneum and Oryzaephilus surinamensis were tested. For the majority of the species and populations tested, both FAO and DDPTTK provided similar results, for the susceptibility to phosphine and thus, the quick test could be used with success for an initial same day screening of phosphine resistance. Among the tested species, the populations recorded with the most frequent survival at the FAO testing dose of phosphine was that of R. dominica. The dissimilar evaluation and characterization of resistance to phosphine between diagnostic protocols is particularly important, as it poses risks in the over or underestimation of the resistance status of a given population. Our data indicate that the DDPTTK could be used to determine resistance to phosphine in the field, before the initiation of fumigations to disinfest stored commodities.

The insecticidal potential of two natural zeolite formulations, Zeocem and Mycostop, was tested against the rice weevil Sitophilus oryzae (L.) and the sawtoothed grain beetle Oryzaephilus surinamensis (L.) on wheat, at the dose rates of 0.25, 0.50, 0.75, and 1 g/kg. The bioassays were carried out under laboratory conditions at three temperature levels (20, 25, and 30οC) and two relative humidity (r.h.) levels (55, 75%). Mortality was recorded after 7, 14, and 21 d of exposure and progeny production was recorded 65 d later. Complete (100%) mortality was achieved only for O. surinamensis adults with Zeocem for most temperature and r.h. combinations tested. Progeny production for this species was extremely low. In contrast, mortality for S. oryzae was much lower and did not exceed 87% after 21 days at any of the combinations tested, while progeny production was high. For O. surinamensis exposed to Mycostop, mortality after 21 days did not exceed 97% for all temperature and r.h combinations, while overall progeny production was low. Moreover, S. oryzae mortality was generally low and did not exceed 56%, while progeny production for this species was high for most temperature and r.h. combinations. Despite the fact that some general trends were evident, the effect of temperarature and r.h. in zeolite efficacy was often found inconclusive. The results of the present study illustrated the insecticidal potential of zeolites for the contol of certain stored product insect species, which requires additional investigation.

In this study we evaluated the efficacy of heat treatment on phosphine resistant and susceptible populations of stored product insects at twenty three different commercial facilities in Greece. Heat treatments were carried out by using special equipment, such as Therminate, TempAir and ThermoNox, applied alone or in combination. The overall temperature range was between 33 and 55 °C and the duration of the heat treatments was between 20 and 39 h. Adults of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), and the sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), were used in the experiments. The field populations were collected from different storage facilities in Greece and were characterized as resistant populations by using the Detia Degesch Phosphine Tolerance Test Kit. Insect mortality was measured at the termination of each trial. Then, the vials were kept in incubator chambers at 25 °C and 65% relative humidity and 65 d later the progeny production was measured in the treated substrate. In light of our findings, in the vast majority of the cases, complete control was observed for both resistant and susceptible populations at all facilities. In general, in the few cases where survival and progeny production was recorded, there was no specific trend towards specific species or population. Overall, based on the current results, heat treatment can be used by the industry as an alternative method for the control of phosphine-resistant adults of R. dominica and O. surinamensis.

We investigated the population growth of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on seven groups of commercially available non-grain commodities. Six powdered spices were used in the first group of experiments: black pepper, clove, nutmeg, allspice, cinnamon and turmeric. The second group of the tested commodities included seven animal products: powdered cow milk, powdered pork zelatin, sheeps’ wool, goat’s skin, ducks’ feathers, dry dog food and dry cat food. The third group of commodities was consisted of six herbs: oregano, spearmint, basil, coriander, laurel and marjoram. The fourth group of commodities contained ten pulses: chickpeas, lentil, split peas, black-eyed peas, beans, soybean flour and whole kernels, lima beans, mung bean, and broad beans. The fifth group comprised six dried fruits: Corinthian currants, sultanas, banana chips, melons, apricots and figs. The sixth group was consisted of five non-grain commodities: cottonseed cake, tobacco, black tea, Turk kahvesi and potato flour. The seventh group included seven nuts: sunflower seeds, pumpkin seeds, pistachios, roasted chickpeas (yellow), almonds, hazelnuts and walnuts. Finally, six cracked containment categories (0% cracked kernels, 5% cracked kernels and 95% intact kernels, 10% cracked kernels and 90% intact kernels, 25% cracked kernels and 75% intact kernels, 50% cracked kernels and 50% intact kernels and 100% cracked kernels) from five pulses were tested: chickpeas, black-eyed peas, mung bean, soybean and split peas. The highest progeny production (3.01 individuals per vial) was recorded on powdered cow milk. On pistachios, split peas, sunflower seeds, soybean flour, pumpkin seeds, walnuts, almonds and coriander, T. granarium built high population densities rapidly, while on roasted chickpeas, cottonseed cake, hazelnuts, chickpeas, dog food and lentils, its population growth was much less. Broad beans, melons, figs, lima beans, beans, Corinthian currants, pork zelatin and potato flour were less suitable diets for the development of this species. On black pepper, clove, nutmeg, allspice, cinnamon, turmeric, sheeps’ wool, goat’s skin, ducks’ feathers, cat food, sultanas, banana chips, apricots, tobacco, black tea, Turk kahvesi, oregano, spearmint, basil, laurel and marjoram, no progeny production was recorded. The proportion of 100% cracked black-eyed peas or mung beans was more suitable for the population growth of T. granarium. Also, the percentages of 50% cracked chickpeas or 10% cracked soybeans enhanced the development of the species, in comparison with the whole kernels of each pulse. Our study indicated that several non-grain commodities are beneficial for the population growth of T. granarium, a fact that should be seriously taken into account in international trade, as this pest may utilize them as “vehicles” of expansion.

In the present study, Carifend® an alpha-cypermethrin-coated net, was evaluated for the control of Lasioderma serricorne and Ephestia elutella in semi-field and field tests in two storage facilities. In the semi-field tests, three Carifend® Multi-Cubicles (CMCs), within which one carton box filled with tobacco was placed, were suspended in three separate rooms. Two MoBe traps were placed, one inside and one outside of each CMC. Three additional tobacco quantities in similar carton boxes, with a MoBe trap on them, were placed in three separate adjacent rooms and served as controls. In each room, 50 L. serricorne and 50 E. elutella adults were released outside of each tobacco quantity and the traps were inspected at weekly intervals for 3 weeks. A similar approach was followed in the field test conducted in a commercial tobacco storage facility. However, no insects were released and the test was based on the naturally-occurring immigrations of populations of E. elutella and L. serricorne from outside the facility or from unprotected tobacco. In semi-field tests, significantly more adults were captured in the first week in the control traps compared to counts from CMCs, either inside or outside. However, differences were significant only in the case of E. elutella. Only one single L. serricorne individual was found in the traps that had been placed inside CMCs, whereas no adult E. elutella were detected inside CMCs. In the field-test, traps that had been placed inside the CMCs captured only 3 and 1 adults of E. elutella and L. serricorne, respectively, during the entire survey period. Results of this study show that Carifend® is highly effective for the control of both species on stored tobacco, and could be further successfully utilized as an alternative method over the use of traditional insecticidal treatments (such as repeated fumigations of phosphine gas) on tobacco.

Simple Summary Reservoir plants are crucial for overwintering pests and their biological control agents. A long-term survey revealed that Capsella bursa-pastoris is a significant host plant, especially for aphids as well as their parasitoids and hyperparasitoids. Twenty-five aphids and eleven parasitoid species were identified on this weed. Myzus persicae and Aphis gossypii were the most commonly recorded aphid species, and Binodoxys angelicae the most frequent parasitoid. Additionally, the monthly distribution of the aphids, parasitoids, and hyperparasitoids showed that C. bursa pastoris fills the host plant gap in the absence of crops. Trophic relations within the community and the importance of C. bursa pastoris were also analyzed in this study. Abstract The reproduction of aphids depends to a great extent on their host plants, an integration that impacts on the successful expansion of overwintering populations. Therefore, a survey was conducted to evaluate the globally distributed Capsella bursa-pastoris as an overwintering host of economically important aphid species, their parasitoids and hyperparasitoids in the southern and western regions of Turkey from November to March in 2006 to 2013. During this survey, 395 samples of C. bursa-pastoris were collected with 25 aphid species recorded. Among aphids that feed on this host, Myzus persicae, Aphis gossypii, Rhopalosiphum padi, Aphis fabae, Aphis craccivora, Lipaphis erysimi, and Brevicoryne brassicae were the most frequently recorded. In total, 10,761 individual parasitoids were identified. Binodoxys angelicae, Aphidius colemani, Aphidius matricariae, Diaeretiella rapae, Ephedrus persicae, and Lysiphlebus confusus were the most abundant aphidiines that emerged from the aphids collected from C. bursa-pastoris. Alloxysta spp. (Hymenoptera: Cynipoidea), Chalcidoidea (unidentified at genus level), and Dendrocerus spp. (Hymenoptera: Ceraphronoidea) were identified as hyperparasitoids on the parasitoids. These findings indicate that C. bursa-pastoris is a key non-agricultural plant that significantly contributes to the overwintering of numerous aphids and their parasitoids, which should be given serious consideration when biological control strategies are designed.

The exploitation of agricultural byproducts and organic side-streams as insect feeding substrates is advantageous for insect farming both from an economic and a sustainability perspective. In this context, in the present study we evaluated the suitability of ten byproducts of the cereal and legume seed cleaning process for the rearing of larvae of the yellow mealworm, Tenebrio molitor, and the lesser mealworm, Alphitobius diaperinus. Byproducts were offered singly to 20 T. molitor and 50 A. diaperinus larvae with provision of carrots as moisture source. After four weeks of undisturbed development, larval weight and survival was evaluated biweekly until pupation. Feed utilization and economic feasibility parameters were determined for each byproduct at the end of the bioassays. Our results show the suitability of several of the byproducts tested for the rearing of T. molitor and A. diaperinus larvae. The best results though among the byproducts tested in terms of larval growth and survival, development time and feed utilization were obtained with larvae fed with lupin and triticale byproducts, which efficiently supported complete larval development. The results of our study aim to boost the integration of circular economy strategies with insect farming practices.

The objective of this special issue is to highlight the current state of research in the field of insects as food and feed, but also other aspects on the exploitation of insect farming. In this editorial, we make a short introduction of the topic of the special issue, briefly present the contributions that are collected in it and offer some thoughts on the future research priorities and challenges that should be addressed. Regarding insect farming, there are additional applications, such as fertilizer, health-promoting products, and cosmetics, that can be produced and utilized, that go far beyond food and feed production.

The aim of this review is to compile up-to-date information on the superworm, Zophobas morio (F.), regarding its biology and ecology, but also its further potential for use as a nutrient source for food and feed. We illustrate certain basic characteristics of the morphology and bio-ecology of this species, which is marginally considered as a ‘pest’ in durable amylaceous commodities. More recent data show that Z. morio can be a valuable nutrient and antimicrobial source that could be utilized further in insect-based feed and food production. The inclusion of this species in aquafeed has provided promising results in a wide range of feeding trials, both in terms of fish development and health. Additional data illustrate its potential for use in poultry, indicating that this species provides comparable results with those of other insect species that are used in feed. Moreover, Z. morio can be a viable waste management agent. This review aims to summarize the available data and underline data gaps for future research, toward the potential of the utilization of Z. morio for human food and animal feed. Based on the data presented, Z. morio appears to be a well-promising insect-based protein source, which potential still remains to be unfold.

The egg parasitoidTrichogramma evanescensWestwood is considered as an efficient biological control agent for managing several lepidopteran pests and it is widely distributed throughout the world. Mass rearing protocols of parasitoids that are currently in use in biocontrol programs require a meticulous quality control plan, in order to optimize their efficacy, but also their progeny production capacity. In this paper, the effect of different factors on the quality control in mass rearing ofT.evenescens, usingPlodia interpunctella(Hübner) andGalleria mellonellaL. as host species, were investigated. The impact of egg agewas significant in the rates of parasitism, for both host species tested. Significantly highest percent of parasitoid emergence was noticed in two day-old eggs for both host species, while one day-old eggs day exhibited the maximum emergence when both species were used togetherin the same trials. Age-dependent storage egg preservation at either 4 or 9°C significantly influenced the parasitism percentages on both species. The highest parasitism percentage was recorded in two day-oldG.mellonellaeggs that are kept for 15 days at 9°C while the lower in one day-oldP.interpunctellaeggs for 60 d storage. Moreover, the highest parasitoid mortality was recorded inT.evanescensreared either onP.interpunctellaorG.mellonellaat 20°C. Rearing of the parasitoid on a mixture of eggs of both host species resulted in higher parasitism, but not always in higher rates of parasitoid emergence. The results of the present work provide useful information that can be further utilized in rearing protocols ofT.evanescens.

Knockdown and mortality of adults of the red flour beetle, Tribolium castaneum (Herbst) and the confused flour beetle, Tribolium confusum Jacquelin du Val, were assessed after exposure to two contact insecticides, chlorfenapyr and cyfluthrin, on a concrete surface. Individuals were rated on a scale for knockdown of exposed adults according to their mobility from 1, representing immobilized adults to 5, representing normally moving (similar to the controls). Only cyfluthrin gave immediate knockdown. Adults were rated at 1, 3 and 7 days post-exposure. After the final assessment, adults were discarded and the same procedure was repeated for 5 consecutive weeks with new adults exposed on the same treated surfaces. Despite initial knockdown, many individuals did not eventually die after exposure to cyfluthrin. In contrast, adults exposed to chlorfenapyr were not initially knocked down after exposure but most died after 7 days. These trends were similar during the entire 5-week residual testing period. The storage of the treated dishes in illuminated or non-illuminated conditions did not affect the insecticidal effect of either insecticide. The results of the present study can be further implemented towards the design of a “lethality index” that can serve as a quick indicator of knockdown and mortality rates caused after exposure to insecticides.

Background The lesser grain borer, Rhyzopertha dominica is a serious pest of stored grains. Fumigation and contact insecticides play a major role in managing this pest globally. While insects are developing genetic resistance to chemicals, hormonal analogues such as s-methoprene play a key role in reducing general pest pressure as well as managing pest populations that are resistant to fumigants and neurotoxic contact insecticides. However, resistance to s-methoprene has been reported in R. dominica with some reports showing a remarkable high resistance, questioning the use of this compound and other related analogues in grain protection. The current study attempts to identify possible molecular mechanisms that contribute in resistance to s-methoprene in R. dominica. Results Transcriptome analysis of resistant and susceptible strains of this pest species identified a set of differentially expressed genes related to cytochrome P450s, indicating their potential role in resistance to s-methoprene. Laboratory bioassays were performed with s-methoprene treated wheat grains in presence and absence of piperonyl butoxide (PBO), a cytochrome P450 inhibitor. The results indicate that PBO, when applied alone, at least at the concentration tested here, had no effect on R. dominica adult emergence, but has a clear synergistic effect to s-methoprene. The number of produced progeny decreased in presence of the inhibitor, especially in the resistant strain. In addition, we also identified CYP complement (CYPome) of R. dominica, annotated and analysed phylogenetically, to understand the evolutionary relationships with other species. Conclusions The information generated in current study suggest that PBO can effectively be used to break resistance to s-methoprene in R. dominica.

Wheat is one of the major crops throughout the Balkan peninsula of Europe. Specific harvest and binning dates can vary depending on the specific geographic region. Grain aeration, wherein ambient air is used at low-volume airflow rates to cool a grain mass to levels that will suppress insect population development, is an under-utilized component of pest management plans for stored wheat. The successful use of aeration can potentially reduce fumigation of stored wheat, which will contribute to the amelioration of increasingly prevalent phosphine resistance. Historical weather data were used from 19 sites in the Balkan region to predict how quickly grains could be cooled through the use of aeration, using a web-based aeration model, and three different starting dates, including 1, 15, and 30 July. The model was used to predict population growth and development of Sitophilus oryzae, the rice weevil, with and without the use of aeration. Results show that, in the northern regions of the Balkans, aeration implemented at the start of binning reduced insect populations far below pest levels in unaerated wheat, and may potentially eliminate the need for fumigations. In more southerly regions, additional chemical inputs, such as fumigation or grain protectants, may be necessary in conjunction with aeration. Results provide guidelines for the increased potential of using aeration for the management of wheat produced and stored in the Balkan peninsula.

In this study, we evaluated nitrogen treatment on phosphine-resistant field and -susceptible laboratory populations of different stored product beetles. Nine trials were conducted in commercial nitrogen chambers with the O2 level set at 1.0%. Two different temperatures&mdash, i.e., 28 and 40 &deg, C&mdash, and three exposure intervals&mdash, i.e., 2.5, 3 and 9 d&mdash, were used in our tests. Adults of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), and the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) were used in the trials. The insects were placed in vials with different commodities per species and population, and their mortality was measured after the termination of each trial. Then, the vials were kept in incubator chambers at 25 &deg, C and 65% relative humidity for 65 d to measure progeny production. Complete parental mortality was observed in all cases for O. surinamensis and S. oryzae, but there was some survival for T. castaneum at 28 &deg, C and 3 d of exposure. In general, progeny production was completely (100%) suppressed, with some exceptions for all species and populations. The results indicate that low oxygen is effective for all species tested, regardless of their resistance status to phosphine, and can be further adopted as an alternative method to mitigate resistance in stored product beetles.

Laboratory bioassays were conducted to evaluate the insecticidal efficacy of a diatomaceous earth deposit from Greece, for a wide range of stored product insects. In this context, populations of five different insect species, Tribolium confusum Jacquelin DuVal, the confused flour beetle, Sitophilus oryzae (L.), the rice weevil, Rhyzopertha dominica (F.), the lesser grain borer, Oryzaephilus surinamensis (L.), the sawtoothed grain beetle, Cryptolestes ferrugineus (Stephens), the rusty grain beetle, which cover a major spectrum of insects species of stored products worldwide, were used in the bioassays. The different treatment of diatomaceous earth (DE) rocks (grinding, diatomaceous enrichment, powder granulometry) led to the creation of five types of formulations (namely DE1, DE2, DE3, DE5 and DE6) that exhibited significant fluctuations in their insecticidal efficacy when applied on wheat. In general, some of the modified formulations were found to be very effective against species such as R. dominica and T. confusum that may be difficult to control at the current labeled doses of commercial DE formulations. Overall, our data clearly indicate that this specific Greek deposit has considerable insecticidal properties, which can be further utilized in designing commercial formulations for insect control at the postharvest stages of durable agricultural commodities, provided that the deposit will be modified at specific enrichment and granulometry levels.

We evaluated different monitoring protocols for phosphine resistance in adults of three populations of the cigarette beetle, Lasioderma serricorne (F.), termed LB, 2KT, and E1. The protocols evaluated were as follows: 1) the Food and Agriculture Organization (FAO) bioassay, i.e., the exposure at 30 ppm of phosphine for 20 h, 2) the dose response, based on the exposure at 50–1,000 ppm of phosphine for 3 d, 3) the Cooperation Center for Scientific Research Relative to Tobacco (CORESTA) bioassay, which is based on exposures of 4 d at 200 ppm, and, if there are surviving individuals, of 10 d at 700 ppm, and 4) Detia Degesch Phosphine Tolerance Test Kit (DDPTTK), based on the evaluation of the exposed insects for short intervals of exposure (in our case 90 min) at 3,000 ppm. From the populations tested, E1 indicated the highest survival in the FAO bioassay. Moreover, adults of this population were able to survive at 200 ppm, in the dose response, in contrast with the other populations. However, both 2KT and E1 gave similar results in DDPTTK, but only E1 had survivors after 7 d postexposure. Finally, only adults of E1 survived the CORESTA bioassay for 200 ppm and 4 d, but not for 700 ppm and 10 d. Our results show that, at least in the range of the populations tested here, there are some trends that are comparable among the different diagnostics for L. serricorne, which can be utilized further in designing a widely adopted standardized protocol.

Diapause concerns the fascinating phenomenon in the biology of insect development which allows better understanding the local adaptation and phenotypic plasticity to seasonal variations in environment. There is lot of reasons to carry out the research on diapause both for fundamental and applied sciences. Photoperiod is one of the main environmental cues followed by insects to predict the forthcoming seasonal changes and to adapt these changes in their life-history traits. Thus, the effect of different photoperiod regimes on development and diapause induction of larvae of the Indian meal moth Plodia interpunctella (Hübner) was evaluated at a constant temperature of 17 °C. Development was significantly faster at a photoperiod of 12:12 light:darkness (L:D) than at 8:16, 10:14, 14:10 and 16:8 L:D. A photoperiod of 12:12 (L:D) induced most larvae (≥ 71%) to enter diapause, while this percentage was slightly lower (60%) at both shorter(8 h) and longer (16 h) day lengths (50%). The different photoperiod regimes did not affect the percentage of adult emergence. Fat and protein composition of the diapausing larvae differed significantly among treatments as well as between diapausing and non-diapausing larvae. Larvae developing from 8:16 (L:D) contained the maximum amount of protein (36.8%) compared to other regimes, while the minimum amount (21.0%) was noted in larvae that developed at 16:8 (L:D). Six types of fatty acids were detected in the larvae: myristic acid (methyl tetradecenoate), palmitoleic acid (9-hexadecenoic acid, methyl ester), palmitic acid (hexadecenoic acid, methyl ester), linoleic acid (9, 12-Octadecadienoic acid (Z, Z), methyl ester), oleic acid [9-octadecenoic acid, methyl ester (E)] and stearic acid (octadecanoic acid, methyl ester). The results also reveal that the percent of fatty acids detected in the diapausing larvae varies significantly and the same trends imply in the interaction of fatty acid and photoperiod regimes. Moreover, three quarters of the total variance was accounted for by the Principal Component Analysis (PCA) of the fatty acids. Different proportions of fatty acids were noted among treatments, suggesting that photoperiod influences a number of key biological traits in P. interpunctella, much more than the percentage of the diapausing larvae per se.

Bioassays were conducted to evaluate the effectiveness of thiamethoxam in different surfaces, against six stored-grain insects, Sitophilus granarius (L.) (Coleoptera: Curculionidae), Sitophilus oryzae (L.) (Coleoptera: Curculionidae), Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae), and Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae). Six different surfaces (concrete, plywood, galvanized steel, linen, plastic, and ceramic tile) treated with thiamethoxam at 0.05 and 0.1 mg/cm2 were used as substrate for adult exposure. Knockdown was recorded after 1, 3, and 7 d of exposure to the treated surface, in order to calculate a Standardized Lethality Index (SLI). Knockdown counts were ranked from ‘0’ to ‘4’, with ‘0’ representing adult insects ‘moved generally’ and ‘4’ representing dead insects. Based on the results, insect knockdown seems leading to mortality than to recovery and the SLI ranking of the target species according to their susceptibility to thiamethoxam showed that S. granarius being more susceptible and decreasing susceptibility in an order of S. oryzae > T. castaneum ≥ O. surinamenis ≥ C. ferrugineus ≥ T. confusum. In general, among the surfaces, thiamethoxam efficacy was lower on linen, wooden, and concrete surfaces, as compared to metallic and plastic surfaces. Nevertheless, at the end of 7-d exposure, all surfaces equally affected thiamethoxam toxicity.

In the present study, we evaluated the insecticidal efficacy of diatomaceous earth (DE) and pirimiphos-methyl for the control of phosphine-susceptible and phosphine-resistant populations of Tribolium castaneum (Herbst) and Sitophilus oryzae (L.). Insecticides were applied on wheat or rice at two doses: DE was applied at 1000 and 2000 ppm and pirimiphos-methyl at 1 and 5 ppm. Adult mortality was measured after 7, 14, and 21 days of exposure, and progeny production capacity on the treated substrates was evaluated 65 days later. For T. castaneum, we found that DE, at 2000 ppm, was able to provide 100% control of two of the three populations tested, while for the third population mortality reached only 84%. Similarly, there were differences in mortality levels after exposure to DE-treated grains between the two S. oryzae populations tested. At 1 ppm, pirimiphos-methyl was not effective for any of the T. castaneum populations tested, but complete mortality was recorded for all populations at 5 ppm. In general, populations of S. oryzae were more susceptible than those of T. castaneum, for both commodities. Our data indicate that both insecticides can be used with success in phosphine resistance management programs, but there are populations of a given species that may be less susceptible, which constitutes a preliminary screening essential.

In the present study, we investigated the insecticidal efficacy of a commercial binary combination of two pyrethroids, cyphenothrin and prallethrin, as structural treatment against adults of Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.), Tribolium confusum Jacquelin du Val and Prostephanus truncatus (Horn) in laboratory bioassays. In a first series of bioassays, the insecticide was applied at its label dose on concrete and metal surfaces, whereas mortality and knockdown levels were recorded after 1, 3, 7 and 14 d of exposure. In a second series of bioassays, the residual efficacy of the insecticide was evaluated on concrete for a period of four months, stored either in continuous darkness or exposed to light. In these bioassays, mortality and knockdown of the exposed insects was measured after 3, 7 and 14 d of exposure. Finally, in a third series of bioassays, we investigated the immediate and delayed effect of the tested formulation on adults of the four insect species after exposure for 1, 3 and 7 d. Based on our results, the application of the tested insecticide as surface treatment can provide efficient control against adults of all four species tested. The surface type did not significantly affect the insecticidal efficacy of the tested formulation, at least for the surfaces tested. Moreover, exposure to light negatively affected the residual activity of the insecticide, as for all insect species tested, mortality was significantly lower on dishes exposed to light than on the ones stored in the dark for storage intervals equal or longer than two months. Finally, reduced delayed mortality was observed for all exposure intervals, as knocked down individuals remained, in most cases, knocked down even 7 d after their removal from the treated dishes.

In the present work we evaluated the effect of alpha-cypermethrin, pirimiphos-methyl and spinetoram on field and laboratory strains of Sitophilus oryzae (L.) and Oryzaephilus surinamensis (L.) with different susceptibility levels to phosphine. The field populations were collected from storage facilities in Greece and were characterized as resistant by using the Food and Agriculture Organization (FAO) protocol, based on the same protocol, populations were characterized as susceptible to phosphine. The insecticides were applied at three dose rates (0.1, 1 and 10 ppm) on wheat and adult mortality was measured after 7, 14 and 21 days of exposure, while progeny production was assessed 65 days later. For S. oryzae populations, complete control was noted at the highest dose on pirimiphos-methyl and spinetoram, while mortality caused by alpha-cypermethrin was 62 and 100% for the field and laboratory populations, respectively. For O. surinamensis, complete control was recorded at the highest dose only on alpha-cypermethrin for the laboratory population, in contrast with the field population, where mortality was only 32% after 21 days of exposure. In general, the variations among populations were negligible for spinetoram, probably due to the fact that the populations tested were not previously exposed to this active ingredient. In contrast, the lowest susceptibility of the field populations to the other two insecticides can be attributed to the fact that these populations might have been exposed to these active ingredients, while any hypothesis for cross-resistance with phosphine has to be examined more thoroughly.

The mould mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) and the flour mite, Acarus siro L. (Sarcoptiformes: Acaridae) are very common stored-product mites found in a wide spectrum of commodities of both plant and animal origin. In this study, we evaluated three zeolite formulations as stored-wheat protectants regarding the management of larvae, nymphs and adults of T. putrescentiae and A. siro at different exposure intervals, i.e., 1, 2, and 5 days (d), and doses, i.e., 200, 500, and 1000 ppm. We found that the zeolite formulations tested here can be effective for the control of both stored-product mite species. Mortality of all stages of T. putrescentiae and A. siro was considerably affected by dose and exposure intervals, i.e. the higher the dose and the longer the exposure time, the greater the mortality. Nevertheless, 100% mortality was not recorded on any of the life stages and formulations tested, even in the case of the highest dose and the longest exposure interval. All zeolite formulations provided the same efficacy level, which was similar for immature stages and adults of both mite species. The results of the present study suggest that longer exposures of the evaluated zeolite formulations are required to increase the efficacy on the control of T. putrescentiae and A. siro.

The insecticidal effect of low temperatures for the control of all life stages of two stored-product insects, Plodia interpunctella and Liposcelis bostrychophila, was evaluated under laboratory conditions. The temperatures tested were 0, − 5, − 10 and − 15 °C, and, at these temperatures, the insects were exposed for 2, 4 and 8 h and also for 1, 2, 3 and 7 days. Regarding P. interpunctella, the most cold-tolerant life stage was larvae, given that 2 days of exposure were needed for complete (100%) mortality at − 10 °C. Moreover, all larvae were dead at − 15 °C even after 2 h of exposure. Eggs of P. interpunctella were susceptible to cold, as mortality was complete after 7, 1 day, 2 and 2 h at 0, − 5, − 10 and − 15 °C, respectively. L. bostrychophila was by far less susceptible than P. interpunctella. For this species, adults were still alive even after 7 days at − 10 °C, while complete mortality was achieved only after 1 day at − 15 °C. Eggs of L. bostrychophila were the most cold-tolerant life stage, as survival was observed even after 3 days at − 15 °C. The results of the present study provide the first data set on which all life stages of P. interpunctella and L. bostrychophila are evaluated for their susceptibility to cold treatments in a standardized series of exposures and temperatures. These results are expected to further encourage the “real world” application of cold treatments for the disinfestation of durable stored-products.

Tobacco beetle, Lasioderma serricorne (F.) (Coleoptera: Anobiidae), is one of the most serious insect pests of stored tobacco, and traps baited with the female-produced sex pheromone, serricornin, are used for monitoring the pest. In two trapping experiments carried out in tobacco warehouses in Greece, two commercially available trap and lure systems for L. serricorne were found to be equally effective in terms of the numbers of beetles trapped. In contrast to previous reports, anhydroserricornin was unattractive and lures containing serricornin and anhydroserricornin were less attractive than lures containing serricornin only. The sex pheromone of the other main insect pest of tobacco, Ephestia elutella (Hubner) (Lepidoptera: Pyralidae), could be added to the lures without affecting the attractiveness of either pheromone to their respective species. Lures remained attractive for at least 4 weeks under field conditions, and, in laboratory tests, release of pheromone could still be detected after 30 days at 27 °C. The stereoisomeric composition of the serricornin in the two commercial lures was similar with high proportions of the attractive (4S,6S,7S)-isomer. The proportion of the (4S,6S,7R)-isomer was low, and this is known to reduce the attractiveness.

Laboratory tests were carried out to examine the efficacy of different exposure intervals (2 h, 4 h, 8 h, 1 d, 2 d, 3 d, and 7 d) on different life stages (adults, pupae, larvae, and eggs) of Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), the confused flour beetle, and Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), the saw-toothed grain beetle (adults, larvae, and eggs) to 0, -5, -10, and -15°C. Larvae and pupae of T. confusum were more cold-tolerant than eggs or adults. Exposure to temperatures of -10°C for 1 d will kill nearly 100% of all life stages of T. confusum. O. surinamensis was more cold-tolerant than T. confusum. Adults of O. surinamensis were not killed when exposed for 1 d at -5°C, but egg hatch was drastically reduced after 2 h of exposure at the same temperature. Eggs and adults of O. surinamensis were more cold-tolerant than larvae. Our study indicates that target insect species and life stage, temperature, and exposure interval should all be considered when cold treatment is selected as a control strategy against T. confusum and O. surinamensis. Facility managers can use these data in planning cold treatments.

The persistence and residual efficacy of two pirimiphos-methyl formulations [emulsifiable concentrate (EC) and capsule suspension (CS)] on wheat were evaluated in laboratory bioassays against adults of Sitophilus granarius, Rhyzopertha dominica and Tribolium confusum. Pirimiphos-methyl was applied at two doses, 2 and 4 mg kg−1, on wheat and a bioassay was initiated at the day of application and every 4 weeks for 7 consecutive months (8 bioassays). In each bioassay, insect mortality was assessed after 7, 14 and 21 d of exposure, whereas after the final mortality count, all individuals were removed and progeny production was evaluated after an additional period of 65 d. Moreover, samples of the treated wheat were taken at the beginning of each bioassay to study the fate of pirimiphos-methyl during the storage period of 7 months by measuring insecticide residues by high performance liquid chromatography (HPLC). Both pirimiphos-methyl formulations provided long-term protection against S. granarius adults. In most cases, complete (100%) mortality was noted, while mortality exceeded 95% after 21 d of exposure even 7 months after application for both doses and formulations. Tribolium confusum mortality did not reach 100% for any of the combinations tested, while a gradual decline of mortality levels was recorded over the 7-month period of storage. Rhyzopertha dominica was the least susceptible species to pirimiphos-methyl with very low mortality levels already after 1 month of storage. The residue analysis results show that pirimiphos-methyl is persistent under the conditions tested, as more than 50% of the initial concentration was still present on the wheat grains after the 7-month period of storage, for both doses and formulations. From the residue analysis results CS was shown to be slightly more persistent than EC, however this was not expressed as a significantly higher insecticidal efficacy of CS over time compared to EC.

In the present work, we evaluated the residual efficacy of spinetoram on grains (wheat and maize) against two stored product insect species, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) and Sitophilus oryzae (L.) (Coleoptera: Curculionidae). All bioassays were conducted with spinetoram at different dose rates, 0.1, 1 and 10 ppm. The treated grains were kept in controlled conditions 25 °C and 65%, five months, in order to investigate the insecticidal effect of spinetoram. Spinetoram residues were measured at 1 ppm right after the application and during the last month. For both tested species, adult mortality was evaluated in the treated grains after 7 and 14 days of exposure. After the termination of the exposure, progeny production (65 d later) was counted. The most susceptible species was R. dominica for both tested commodities, given that mortality was reached 100% even after 7 days of exposure at the lowest dose rate of 0.1 ppm. Regarding progeny production numbers of R. dominica were suppressed, in contrast with S. oryzae, in which survival was high even at 10 ppm. Based on our results, spinetoran was quite effective on maize (86.6%) than on wheat (80.0%); however, the insecticidal efficacy remained stable for 5 months after the treatment at the tested conditions. Hence, the formulation remained stable for the whole storage period.

The use of insecticide-treated nets has lately attracted scientific interest for the management of mosquitoes and related species, as well as for crop pest control and the protection of stored agricultural commodities. In our study, the effect of Carifend®, an alpha-cypermethrin-coated polyester net, on adults of the two most important stored-tobacco insect pests, Lasioderma serricorne and Ephestia elutella, was evaluated in laboratory bioassays. Carifend® was applied to the bottom of plastic Petri dishes, whereas an additional series of dishes with net material without insecticide was also prepared and served as control. Twenty beetles or moths of mixed sex were placed in each dish. Insects were exposed to the substrates for 1, 5, 15, 30, 60, 90, 120 and 240 min and for 12 and 24 h. Immediate mortality and knockdown effect were measured after each exposure. Afterward, all surviving individuals were placed in untreated plastic dishes and delayed mortality, as well as percentage of knocked down insects, were counted after 1, 3, 5 and 7 days. Immediate mortality was very low for both species tested, even after 24 h of exposure. In contrast, immediate knockdown was high, especially for exposure intervals longer than 60 min. After insect removal from dishes with Carifend®, the high knockdown percentages were gradually transformed in most cases to delayed mortality. Based on our results, Carifend® can provide a satisfactory level of protection for stored tobacco against these two major tobacco insect pests, at least at the conditions tested here.

Laboratory bioassays were conducted to evaluate the efficacy of two insecticides, spinetoram and thiamethoxam, applied alone or in combination to wheat against adults of Sitophilus granarius, S. oryzae, Oryzaephilus surinamensis, Tribolium castaneum and Cryptolestes ferrugineus, as well as adults and larvae of T. confusum. Spinetoram was applied at two (0.25 and 0.5 ppm) and thiamethoxam at three (1, 2 and 5 ppm) dose rates, whereas all binary combinations of the insecticide concentrations were also tested. Insect mortality was determined after 1, 2, 7, 14 and 21 d of exposure, while 65 d later progeny production was evaluated. In the case of T. confusum larvae, adult emergence was estimated 4 weeks after the initiation of the bioassays. Among the species examined, S. granarius and S. oryzae were the most susceptible to spinetoram in terms of parental mortality, however progeny production was significantly suppressed only in the case of S. granarius. In contrast, O. surinamensis, T. confusum and T. castaneum were the least susceptible to the specific dose rates of spinetoram tested. Thiamethoxam was effective against all species tested providing high levels of parental mortality and progeny production suppression. However, the combined application of thiamethoxam and spinetoram at the specific dose rates tested did not exhibit any additive or synergistic effect against the stored-product beetle species examined. Still, the combined application of these active ingredients did not exhibit any antagonistic effect.

Bioassays were carried out in order to assess the insecticidal value of the neonicotinoid thiamethoxam in different concentrations against seven important beetle species that are major pests of stored grains. These species were Prostephanus truncatus (Horn), Rhyzopertha dominica (F.), Sitophilus oryzae (L.), Sitophilus granarius (L.), Oryzaephilus surinamensis (L.), Tribolium confusum Jacquelin du Val, and Cryptolestes ferrugineus (Stephens). Adults of these species were exposed to grains treated with thiamethoxam at dose rates of 0 (control), 0.01, 0.1, 0.5, 1, 2, 5 or 10 ppm. Our results indicate that with the increase of the insecticide concentration, there was also an increased adult mortality and a reduction in progeny production. To illustrate the relative sensitivity to thiamethoxam of the seven insects, starting with the most susceptible, we can classify them as P. truncatus > R. dominica = S. granarius = S. oryzae > T. confusum = O. surinamensis > C. ferrugineus. The findings of the present research show that thiamethoxam can be recommended for its efficacy at a rate of 10 ppm and duration of 14 days that could be used to control all insects and their progeny.

In the present study, the residual efficacy of an alpha-cypermethrin-coated net (Carifend®, BASF AG, Ludwigshafen, Germany) was evaluated in laboratory studies against four species of stored product insects. The insecticide-treated net was fitted into the bottom of plastic petri dishes, whereas two other sets of dishes (without net, with net without insecticide) served as controls. The insects used in the bioassays were Sitophilus oryzae, Tribolium confusum, Oryzaephilus surinamensis and Prostephanus truncatus. Adults of these species were exposed every 30 d for a total of 90 consecutive days in total. Based on the results, the insecticidal effect of the net remained at high levels during the entire experimental period, indicating its high residual effect. Among the species tested, T. confusum was the least susceptible. Carifend® can be a valuable tool for the protection of stored products against storage insects, and its use can be further examined towards this direction.