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Simple Summary: Natural insecticides are currently given high priority in Integrated Pest Management (IPM) protocols. To this end, diatomaceous earth (DE) has gained a lot of attention as an environmentally friendly alternative to conventional insecticides that can successfully repel and control a diverse variety of the most important stored-product insect pests, such as the species Sitophilus, Rhyzopertha, Tribolium, and others. However, most published research about the DEs' insecticidal efficacy has been conducted in simplistic short-term laboratory experiments, excluding the evaluation of the persistence of such ingredients in grain applications. In this study, we evaluated two different DE formulations derived from a single deposit from Greece, when applied in wheat and maize against two primary stored-product insect pests, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). Based on the results, the DE application was effective and persistent as a grain protectant against major stored-product insects for a storage period of six months. This study provides more evidence for the successful utilization of these natural insecticides for long-term protection of stored products from insect infestations, as an alternative to residual insecticides and fumigants that are commonly used in stored-grain protection systems or as part of integrated pest management (IPM) strategies. We evaluated the persistence and efficacy of two different, in granulometry and content of diatoms, diatomaceous earth (DE) formulations (i.e., DE5 and DE6), against two major beetle species of stored products, i.e., Sitophilus oryzae (L.) (Coleoptera: Curculionidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). The formulations were applied as powders in soft wheat and maize in two doses of 500 and 1000 mg kg−1 (ppm). Samples of the treated grains were taken on the day of application and every 30 days until completion of the six-month period of storage. Adults of S. oryzae and R. dominica were exposed to the treated grains at 25 °C and 55% relative humidity, and the mortality was measured after 7, 14, and 21 days of exposure. Rhyzopertha dominica survival was not affected by any combination of DE formulation, dose, and commodity. Contrariwise, the DEs caused significant adult mortality of S. oryzae, in most of the cases tested. We observed that DE6 was equally effective in both wheat and maize, and no considerable variations were observed in S. oryzae mortality during the 6-month experimental period. Furthermore, DE6 was more effective against S. oryzae than DE5, a difference that could have potentially contributed to the variations in the diatom granulometry between these two DEs. Thus, a DE treatment of 1000 ppm was shown to provide long-term protection of wheat and maize against S. oryzae, but this is strongly dependent on the DE formulation, commodity, and insect species. Overall, such natural resource-based inert silicaceous deposits could be used with success in stored-product protection with only some minor modifications, such as sieving and drying of the raw deposit. [ABSTRACT FROM AUTHOR]

Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), commonly known as the lesser mealworm, is a significant pest that infests stored grains and other amylaceous commodities. In addition, the species has also been recognized as a viable and environmentally friendly protein source. However, there is still a lack of comprehensive research on the developmental response of this species across various temperature and moisture conditions. This study investigates the impact of temperature and moisture content of the commodity on the population growth of the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae). In the first series of bioassays, the progeny production of A. diaperinus adults was recorded after 50 days of incubation under a range of temperatures from 25 to 40 °C in cracked soft wheat with 11.3% moisture content, while in the second series, the moisture content of the wheat was adjusted to 5, 10, 15, and 20%, at 30 °C. Our results show that temperature largely influences parental adult mortality of A. diaperinus. The most suitable temperatures for optimal larval development and adult survival were found to be within the spectrum of 25 to 32 °C. Moreover, we found that the moisture content of the wheat that served as rearing media was also a factor of significance, since a gradual decrease in the larval numbers was observed with an increase in the moisture content. The findings of this study provide data to further enhance the pest control strategies of A. diaperinus in poultry farms but also to establish mass rearing standards and facilitate the production of the species for efficient use as food and feed. [ABSTRACT FROM AUTHOR]

Certain lures are marketed toward particular pests or classes of pests, while others might be multi-species lures. Investigative aims for this study included both which trap was most sensitive and whether different combinations of traps and attractants were delivering novel information about the stored product insect community. Comparisons were made for all combinations of 3 commercial traps and 4 different attractants plus an untreated control on the capture of stored-product insects for 2 consecutive years in 3 food processing facilities in Central Greece. The traps used in the experiments were Dome Trap (Trécé Inc., USA), Wall Trap (Trécé) and Box Trap (Insects Limited, Ltd., USA). The attractants that were evaluated were 0.13 g of (i) PantryPatrol gel (Insects Limited), (ii) Storgard kairomone food attractant oil (Trécé), (iii) wheat germ (Honeyville, USA), and (iv) Dermestid tablet attractant (Insects Limited). The traps were inspected approximately every 15 days and rotated. A total of 34,000+ individuals were captured belonging to 26 families and at least 48 species. The results indicated that Indian meal moth, Plodia interpunctella (Hübner), red flour beetle, Tribolium castaneum (Herbst), and cigarette beetle, Lasioderma serricorne (F.) were the most abundant. Although there were noticeable differences among the different traps and attractants for specific species, all combinations provided similar information on population dynamics. Generally, Dome traps baited with either the oil or the gel, were found to be the most sensitive. The results of the present study demonstrate the importance of long-term trapping protocols, as a keystone in IPM-based control strategies in food processing facilities. Graphical Abstract [ABSTRACT FROM AUTHOR]

Simple Summary: Insecticides are currently the most effective method to control stored product insect pests worldwide. However, insecticide resistance poses a continuous threat to the viability of these management tools and thus, on food availability. Since there is very limited information available on the existence of resistant/tolerant insect populations in Greece, the objective of our study was to investigate the tolerance status of insect populations sampled from Greek warehouses and silos to a wide range of insecticides. According to our data, all field-collected insect populations indicated different patterns of tolerance, suggesting the occurrence of possible resistance to widely used insecticides. Our findings can be used for the reduction of the cases of control failures by revising the current pest management practices followed by Greek farmers and operators in stored product protection. The protection of stored products from insect pests is mainly based on suppressive methods by using contact and gaseous insecticides, globally. Following their continuous and improper use, insecticide resistance has been observed in several major insect species and pose a continuous threat to the sustainability of a wide range of active ingredients that are currently in use in stored product protection. In the present work, on-site samplings of insect populations were carried out in local warehouses containing different types of cereals. The collected insects, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) and Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae), were reared under laboratory conditions to determine tolerance/resistance to widely used insecticides, using different diagnostic protocols. Laboratory populations of the same species were also examined for comparative purposes. Adult knock down and mortality of all populations indicated different patterns of tolerance to phosphine, deltamethrin, cypermethrin, and pirimiphos-methyl. In many cases, the recommended label doses were not able to completely control some of these populations, regardless of their origin, i.e., field-collected or laboratory. The results of the present work underline the importance of population on the efficacy of insecticides that are currently in use in stored product protection. [ABSTRACT FROM AUTHOR]

We evaluated the relative population growth of two stored-product insect species in the genus Trogoderma, the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), and the warehouse beetle, Trogoderma variabile Ballion (Coleoptera: Dermestidae). Ten adults of each species were placed in vials containing wheat or paddy rice. These tests were performed at 27 and 32°C and the number of adults in the vials were counted after 35 and 70 days. For all the time intervals and temperatures of both species on wheat, the resulting larval abundances were similar, with the exception of 27°C at 70 days where more T. variabile larvae developed. At the higher temperature, both species had similar population growth on rice. However, the success was mixed at 27°C with T. granarium having a greater abundance after 35 days, while T. variabile dominated after 70 days. Frass production in both commodities was usually similar for the two species, but greater frass production occurred by T. variabile on wheat after 70 days at 27°C, while T. granarium produced more frass on rice after 35 days at 32°C. Both species nearly always caused equivalent commodity damage. Our research suggests that under ideal conditions these two closely, but very differently treated species in commerce from the genus Trogoderma have comparable population growth, and cause similar damage on wheat and rice. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The population growth of different strains of the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae), a key pest of stored maize, was evaluated at a range of temperatures. Three different strains of P. truncatus with different geographic origins (USA, Mexico and Tanzania) were left for 45 or 70 d to develop and reproduce under six temperatures (25, 30, 32, 35, 38 and 40 °C). Progeny production and maize-infestation indicators (frass, damaged maize kernels) were examined to estimate possible differences between the strains in terms of development performance and optimal thermal requirements. Population growth of the species appeared to be affected by the combination of temperature and/or developmental period. The optimum temperature range for fast development and serious infestations was found to be 25–32 °C, which resulted in newly-emerged adults after 45 days. Differences were observed between the strains, both in terms of their growth rate and the damage they caused on the kernels over time. The present study aims to highlight how the strain is a factor of significance for P. truncatus based on the different thermal responses. These data can support more accurate prediction or elimination of future infestations, targeting immediate and early detection of the pest in areas where it is likely to establish. • Prostephanus truncatus thrived at 25–32 °C while growth decreased above 35 °C. • Population growth rate differed among the strains of P. truncatus at optimal temperatures. • Prostephanus truncatus completed one generation within 45 days at optimal temperatures. • Prostephanus truncatus infested over 50% of maize within 45 days of incubation. • Insect infestation led to damaged maize at >37 °C, but without progeny production. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of temperature and relative humidity (RH) on the insecticidal effect of diatomaceous earth (DE) at two concentrations, 500 and 1000 ppm, on wheat, for the control of Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae), Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae). These bioassays were carried out in all combinations of four temperature levels (15, 20, 25, and 30 °C), and two relative humidity levels (55 and 75%). Cryptolestes ferrugineus and O. surinamensis were found to be much more susceptible to the DE-treated wheat than T. confusum, but the increase of the DE dose increased the mortality level for all three species. Although the increase of temperature and the decrease of RH increased insect mortality in some of the combinations tested, the reverse was observed in some treatments, suggesting that there are considerable differential effects of these factors in DE efficacy. The increase of insect exposure from 1 to 21 days notably increased insect mortality, suggesting that exposure is a critical factor that may alleviate possible differential effects of certain abiotic conditions. The results of the present work provide data that illustrate the viability of the utilization of DE in stored product protection, as alternatives to chemical control methods. [ABSTRACT FROM AUTHOR]