Sitophilus Granarius Research Articles

Persistence and residual toxicity of two pirimiphos-methyl formulations on wheat against three stored-product pests

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.

Comparison of insecticidal efficacy of four natural substances against granary weevil (Sitophilus granarius [L.]) adults: does the combined use of the substances improve their efficacy?

Laboratory tests were carried out to evaluate the insecticidal efficacy of different natural inert dusts (diatomaceous earth, wood ash, quartz sand) and the leaf powder of Azadirachta indica A. Juss. against granary weevil (Sitophilus granarius [L.]) adults. The efficacy of the substances was tested individually and in combination with each other. The substances were applied at different concentrations, and bioassays were carried out at four different temperatures (20, 25, 30 and 35°C) and two different relative humidity (RH) levels (55% and 75%). The adult mortality was recorded after the 7th, 14th and 21st days of exposure. The progeny production of individuals exposed to different combinations was also assessed. Wood ash proved to be the most efficient inert dust in our research. We detected 100% mortality in the treatment exposed to a higher concentration (5 w%) of wood ash at 35°C and 55% RH after 7 days of exposure. A lower RH level had also a negative impact on the progeny production. We can conclude that wood ash can be efficient in controlling granary weevil adults as a single substance or in combination with other substances. Further surveys should focus on the impact of the wood ash dose rates. Due to the high percentage of area covered with forest in some European countries, the main ingredient is present locally, but additional surveys are needed to help improve the practical use of wood ash.

Chemical composition and insecticidal activity of edible garland (Chrysanthemum coronarium L.) essential oil against the granary pest Sitophilus granarius L. (Coleoptera)

The essential oil composition and biological activities of Chrysanthemum coronarium L. from three locations in Cyprus were investigated. A total of 35 components were identified in the oils representing 86.2 ± 0.7%–93.8 ± 0.0% (n = 3) of the oils. Camphor 25.2 ± 0.1%–9.1 ± 0.3%, santolinatriene 21.7 ± 0.1%–3.6 ± 0.1%, yomogi alcohol 12.6 ± 0.1%–3.6 ± 0.1%, cis-chrysanthenyl acetate 10.7 ± 0.1%–6.8 ± 0.1% and bornyl acetate 11.0 ± 0.5%–5.7 ± 0.0% were identified as the main components. Highest DPPH scavenging and PRAP activity was observed for the Lefkoşe sample (49.59 ± 0.19% (n = 5) and 812.77 ± 4.34 AU (n = 5)). Highest phytotoxic activity against Lemna minor L. was observed for the Salamis sample (100.0%). Lefkoşe sample showed the highest insecticidal activity (97.82 ± 1.79% mortality, S. granarius). Bornyl acetate/cis-chrysanthenyl acetate/hexadecanoic acid and camphor/santolinatriene/ yomogi alcohol chemotypes of C. coronarium are proposed from Cyprus samples according to cluster analysis of the oils together with the literature data.

Insecticidal effect of spinetoram and thiamethoxam applied alone or in combination for the control of major stored-product beetle species

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.

Acute and persistence effects of oil of Hippophae rhamnoides and Calendula officinalis on Sitophilus granarius (Coleoptera: Curculionidae) in stored maize

Herbal oil vapours from Hippophae rhamnoides L. (Elaeagnaceae), and Calendula officinalis L. (Asteraceae) were tested for their toxicity against the adults of Sitophilus granarius L.. According to our hypothesis the mentioned oils can become potential bioagents against stored product pests. The results revealed that both studied essential oils exerted strongly toxic effect on S. granarius, but C. officinalis triggered higher mortality. The efficacy (94.62±2.63%) was reached after a 48-h exposure to H. rhamnoides oil at 2 ml kg–1 while the application of 2 ml kg–1 of C. officinalis oil for 24 h produced 98.94±1.00% mortality rate. Insect mortality was hyperbolically-featured, and increased with the duration of the exposure to the examined oils. Mortality was 100% at 5 ml kg–1 of H. rhamnoides after 24-h duration of its application, while with C. officinalis the same value could be reached after a 12-h exposure to the oil. The progeny pronouncedly recovered from the treatment of both essential oils applied.

Bioefficacy of enhanced diatomaceous earth and botanical powders on the mortality and progeny production of Acanthoscelides obtectus (Coleoptera: Chrysomelidae), Sitophilus granarius (Coleoptera: Dryophthoridae) and Tribolium castaneum (Coleoptera: Tenebrionidae) in stored grain cereals

Abstract Food losses caused by insects during postharvest storage are of paramount economic importance worldwide, especially in Africa. Laboratory bioassays were conducted in stored grains to determine the toxicity of powders of Eugenia aromatica and Moringa oleifera alone or combined with enhanced diatomaceous earth (Probe-A® DE, 89.0% SiO2 and 5% silica aerogel) to adult Sitophilus granarius, Tribolium castaneum and Acanthoscelides obtectus. Adult mortality was observed up to 7 days, while progeny production was recorded at 6–10 weeks. LD50 and LT50 values for adult test insects exposed to plant powders and DE, showed that A. obtectus was the most susceptible towards the botanicals (LD50 0.179% and 0.088% wt/wt for E. aromatica and M. oleifera, respectively), followed by S. granarius. Tribolium castaneum was most tolerant (LD50 1.42% wt/wt and 1.40% wt/wt for E. aromatica and M. oleifera, respectively). The combined mixture of plant powders and DE controlled the beetles faster compared to the plant powders alone. LT50 ranged from 55.7 h to 62.5 h for T. castaneum exposed to 1.0% M. oleifera and 1.0% DE, and 0.5% E. aromatica and 1.0% DE, respectively. Botanicals caused significant reduction of F1 adults compared to the control. Combined action of botanical insecticides with DE as a grain protectant in an integrated pest management approach is discussed.

Larval cannibalism and fitness in the stored grain weevils Sitophilus granarius and Sitophilus zeamais

Resource limitation is an important determinant of life history and behavior while mediating competition and reproduction among organisms. Discreet and closed systems such as grain kernels and seeds impose drastic restrictions to grain beetles that spend their immature stages within a single kernel selected by their mother. This is the case of internally feeding stored grain beetles, such as the grain weevils. Female egg-laying decisions and larval competition largely determine resource limitation for such insects where clustered egg distribution and contest competition with larval interference and cannibalism take place. As the clustered eggs within a grain lead to larval competition and conspecific weevil larvae face each other off during development allowing the emergence of one or two larvae per kernel, we hypothesized that such competition and consequent cannibalism will have fitness consequences for the competing individuals and their offspring. Thus, larvae of the granary weevil (Sitophilus granarius L.) and the maize weevil (Sitophilus zeamais Motsch.) were subjected to larval competition with cannibalism, and lack of it, to assess the potential fitness consequence of cannibalism on these non-carnivorous pest species of stored grains. Larval cannibalism reduced developmental time of maize weevil, but not of granary weevil. However, such condition led to heavier adult weevils of both species exhibiting higher reproductive output generating more and better quality progeny than non-cannibal weevils. These findings indicate direct nutritional benefits of cannibalism to grain weevils favoring their status of key pest species of stored cereal grains.

Insect frass in stored cereal products as a potential source of Lactobacillus sanfranciscensis for sourdough ecosystem.

Insect frass samples were collected from Drosophila melanogaster, Plodia interpunctella, Rhyzopertha dominica, Sitophilus granarius, Sitophilus oryzae, Sitophilus zeamais, Tribolium confusum and Tribolium castaneum to elucidate if they can be the origin of Type I sourdough micro-organisms (Lactobacillus sanfranciscensis and Candida milleri). Selective enrichments were carried out to isolate lactic acid bacteria (LBA) and yeast. A metagenetic analysis, targeted on bacterial 16S rRNA gene and fungal ITS region, was performed by using Illumina MiSeq protocol. In cultivation conditions, Lactococcus garvieae and Rhodotorula mucilaginosa were the most frequently species among LAB and yeasts respectively. The Next Generation Sequencing approach revealed that Enterobacteriaceae, Pseudomonadacae and Bacillaceae were the dominating taxa, accounting for 61% of the bacterial community. Lactobacillus genus showed a relative abundance of only 0·36%, but L. sanfranciscensis proved to be the species most frequent between lactobacilli and predominant in faecal samples of T. castaneum and T. confusum larvae. The core fungal microbiota was constituted by Saccharomycetales, Pleosporaceae and Nectriaceae that attained the 51% of recognized OTUs. While the most abundant yeast genus was Candida (17·1%), sequences belonging to C. milleri were not found. Frass released by the insects of stored cereal products can be the natural reservoir of L. sanfranciscensis. Insect dejections are potential sources of novel strains for controlled bakery productions.

Detection and identification of five common internal grain insect pests by multiplex PCR

Consumer demands for better quality food have led to research on new tools aimed at early detection of insect pests in agro food industries. In these industries, internal grain feeders are the most concerning pests because of being the first colonizers of stored grain and transmitting harmful micro-organisms, such as fungi and bacteria, which affect both food quality and human health. The immature stages of these cosmopolitan pests develop and feed inside the grain kernels, easily evading visual analysis in food industries. To avoid the consequent underestimation of contamination by internal pest species, a multiplex PCR approach for the detection and identification of the five most concerning primary pests that develop and feed hidden inside the grain kernels (Rhyzopertha dominica, Sitophilus granarius, S. oryzae, S. zeamais and Sitotroga cerealella) has been developed. Results have demonstrated that the designed protocol can be used for the diagnosis of grain contamination with high sensitivity (0.1 pupa/kilo of rice, except for R. dominica 10 pupae/kilo). This tool proved to be specific when 46 other species potentially present in grain commodities were tested, and to detect all developmental stages of S. zeamais in different kinds of grain (barley, maize, oat, spelt, rice and wheat) and pasta (macaroni). Detection was even possible when grain was treated with CO2. Finally, in order to confirm its applicability in food industries, this method has also been tested in real commercial grain samples from a pasta mill. The multiplex PCR method presented here could be of great help when making commercial decisions aimed at satisfying the current market demands.

Early invaders: farmers, the granary weevil and other uninvited guests in the Neolithic

The Neolithic and the spread of agriculture saw several introductions of insect species associated with the environments and activities of the first farmers. Fossil insect research from the Neolithic lake settlement of Dispilio in Macedonia, northern Greece, provides evidence for the early European introduction of a flightless weevil, the granary weevil, Sitophilus granarius, which has since become cosmopolitan and one of the most important pests of stored cereals. The records of the granary weevil from the middle Neolithic in northern Greece illuminate the significance of surplus storage for the spread of agriculture. The granary weevil and the house fly, Musca domestica were also introduced in the Neolithic of central Europe, with the expansion of Linear Band Keramik (LBK) culture groups. This paper reviews Neolithic insect introductions in Europe, including storage pests, discusses their distribution during different periods and the reasons behind the trends observed. Storage farming may be differentiated from pastoral farming on the basis of insect introductions arriving with incoming agricultural groups.

Toxicity and protectant potential of Piper guineense (Piperaceae) and Senna siamea (Fabaceae) mixed with diatomaceous earth for the management of three major stored product beetle pests

ABSTRACTThere is a dearth of knowledge on the available sources of botanical products for smallholder farmers in Africa and their bioactivity against stored-product pests. Many locally available plants across Africa exhibit both promising insecticidal, medicinal activity and are nutrient rich yet remain underutilized. Laboratory studies on toxicity of powders of Senna siamea and Piper guineense alone or combined with diatomaceous earth (DE) to adult Sitophilus granarius, Tribolium castaneum and Acanthoscelides obtectus were conducted in stored grains. Adult mortality was observed up to 7 d while progeny production was recorded 6–10 weeks. Adult A. obtectus were most susceptible (LD50 0.0084% and 0.0696% wt/wt for S. siamea and P. guineense, respectively), followed by S. granarius. T. castaneum was most tolerant (LD50 0.6589% and 0.6829% wt/wt for S. siamea and P. guineense, respectively). Combination of plant powders and DE controlled the beetles faster compared to the plant powders alone. LT50 ranged from 20 h to 101 h for T. castaneum exposed to 1.0% S. siamea and 1.0% DE, and 0.5% P. guineense and 1.0% DE, respectively. Botanicals caused significant reduction of F1 adults compared to the control. The potential of using botanicals combined with DE to control stored-product insects is discussed.

Nanoemulsion of Camphor (Eucalyptus globulus) Essential Oil, Formulation, Characterization and Insecticidal Activity against Wheat Weevil, Sitophilus granarius

Nanoemulsion of Camphor (Eucalyptus globulus) Essential Oil, Formulation, Characterization and Insecticidal Activity against Wheat Weevil, Sitophilus granarius

EFFECT OF HARVEST DATE, TRANSPORTATION MEANS, AND STORAGE METHOD, ON THE INFEST OF WHEAT AND MAIZE WITH STORE INSECTS

This research was conducted at special farms in Shebin Elkom locality during the period from November, 2012 till October, 2016 to study the effect of planting wheat at different times on the infestation of the granary (wheat) weevil, Sitophilus granarius (L.), (Coleoptera: Curculionidae, along one year of storing at five tools (Metal silos, Mud silos, Polyethylene bags, Jute bags, Plastic fiber bags). Wheat and maize grain samples (100 g) of each store model of stored grains were examined by eye and with the aid of handle lens (6 x) to calculate the average number of weevil insects per 100 g. Treatments were replicated three times. Statistical analysis of the obtained results indicated that there were significant differences in the annual weevil numbers among the planting times, the best planting time for wheat grains is 13 November because it has the lowest infestation numbers of weevil insects recording 740 weevil / 100 g wheat grains, while the highest weevil numbers was recorded with the planting time 10 November giving 15796 weevil / 100 g wheat grains, the best planting time for maize grain is 15 May because it has the lowest infestation numbers of weevil insects recording 220 weevil / 100 g maize grains, while the highest weevil numbers was recorded with the planting time 15 May giving 1480 weevil / 100 g wheat grains. Regarding to the storing tools with wheat grains, results indicated that there were significant differences in the annual weevil numbers between plastic fiber bags and all other tools recording the lowest numbers of granary weevil insect 2913 individual / 100 g. The highest annual numbers of granary weevil recorded in mud silos and polyethylene bags (3793- 6856 weevil / 100 g) respectively, with maize grains results indicated that there were significant differences in the annual weevil numbers between jute bags and all other tools recording the lowest numbers of granary weevil insect 1031 individual / 100 g. The highest annual numbers of granary weevil recorded in metal silos and plastic fiber bags (1513- 1720 weevil / 100 g) respectively. From the obtained results it could be concluded that the suitable planting time to cultivate wheat is 13 November which resulted the lowest numbers of weevil insects, as well as the suitable tool for wheat grain storing is plastic fiber bags in comparison with other tools and the suitable planting time to cultivate maize is 15 May which resulted the lowest numbers of weevil insects, as well as the suitable tool for maize grain storing is Jute bags in comparison with other tools.

Field efficacy of brief exposure of adults of six storage pests to nitrogen-controlled atmospheres

The efficacy of a brief exposure (1, 7, and 10 days) to a nitrogen-controlled atmosphere (N-CA) for major storage<br />pests in a field validation study in the Czech Republic is reported. The main goal was to estimate how quickly the<br />mobile adult stages of six species of storage beetles (Oryzaephilus surinamensis, Cryptolestes ferrugineus, Tribolium<br />confusum, Tribolium castaneum, Sitophilus granarius, and Sitophilus oryzae) are killed after introduction of the<br />infested commodity to prevent their further spread to the surrounding storage bins. The trials were conducted in a<br />metal bin containing 25 t of seeds using the system of continual top-down nitrogen filling to replace the oxygen. The<br />composition of N-CA in the silo was measured continually. The target N-CA concentration (i.e., ≤ 1% O<sub>2</sub> and 99% N<sub>2</sub>)<br />was reached at the bottom of the silo after 12 h of the purging phase of nitrogen silo filling. A one-day exposure to<br />N-CA corresponds to top-down filling, which initially gives higher concentrations of N2 in the upper than in the lower<br />part of the silo: low efficacy was reached at the silo bottom (0–33.3%), while higher efficacy (16.7–100%) was reached<br />at the top of the silo bin. The mortality variation at both locations was species dependent: the most sensitive was O.<br />surinamensis, and the least sensitive were S. granarius and S. oryzae. Seven days of N-CA exposure led to 100% mortality<br />of all tested species except for S. granarius (96.7% mortality at the bottom), while 10 days of N-CA exposure led<br />to 100% mortality of all adults located at both the bottom and the top of the silo. This experiment showed that one<br />day of exposure to N-CA caused significant mortality to reduce the spread of insects from the top of the silo but not<br />from the silo bottom, and 10 days of exposure completely prevent the adult mobile pest stages of all tested species<br />from spreading from the treated silo and causing cross-infestation in the storage facility.

Insecticidal effects of extracts of Humulus lupulus (hops) L. cones and its principal component, xanthohumol.

Insecticidal effects of the dichloromethane, ethyl acetate, acetone, ethanol and methanol extracts of Humulus lupulus (hops) L. cones and its principal components, xanthohumol was investigated on five stored pests, Sitophilus granarius (L.), Sitophilus oryzae (L.), Acanthoscelides obtectus (Say.), Tribolium castaneum (Herbst) and Lasioderma serricorne (F.). The mortality of adults of the insects treated with 2, 5, 5, 10 and 20 mg ml̠-1 concentrations of the extracts and xanthuhumol was counted after 24, 48, 72, 96 and 120 h. In order to determine the toxic effects of the substances tested against all tested insects, durations for 50% mortality of the adults, and LD50 values were also determined in the first 48 h by probit analysis. Our results also showed that xanthohumol was more toxic against the pests in comparison with the extracts applications. LD50 values for xanthohumol were found to be low dose as compared with the extracts. Xanthohumol was more toxic against S. granarius (L.) with 6.8 µg of LD50 value. Among the extracts, methanol extract was less effective than other extracts against all tested insects. The ethyl acetate extract of H. lupulus cones was the most effective extract against the tested pests. The quantitative amounts of xanthohumol in the extracts were determined using a high-performance liquid chromatography. The quantitative data indicated that amount of xanthohumol in the extracts increased with increase of polarity of the solvents used from methanol to dichloromethane. The methanol extract contained the high amount of xanthohumol with 5.74 g/100 g extract (0.46 g/100 g plant sample).

Competition of three species of Sitophilus on rice and maize.

Laboratory tests were carried out in order to examine competition among three congeneric species on rice and maize: the granary weevil, Sitophilus granarius, the rice weevil, Sitophilus oryzae and the maize weevil, Sitophilus zeamais. For this purpose, a total of 30 adults were placed in vials that contained 50 g or either rice or maize: 30 adults of S. granarius, 30 adults of S. oryzae, 30 adults of S. zeamais, 15 adults of S. granarius+15 adults of S. oryzae, 15 adults of S. granarius+15 adults of S. zeamais, 15 adults of S. oryzae +15 adults of S. zeamais, and 10 adults of S. granarius+10 adults of S. oryzae+10 adults of S. zeamais. After 62 days at 30°C and 65% relative humidity the number of individuals of each species were counted. Insect damaged kernels (IDK), weight of frass and grain weight were measured. When each species was alone, S. granarius had the lowest numbers of adults in both grains, which did not exceed 34 adults/vial, and S. oryzae numbers were always higher than other species. For S. oryzae and S. zeamais, the numbers of adults were considerably higher on rice than on maize. On rice, S. oryzae numbers ranged between 281 and 563 adults per vial, while for S. zeamais between 137 and 372 adults per vial. At the same time, for both species on maize, adult numbers did not exceed 54 adults per vial. The number of S. oryzae adults were constantly higher than the other species in all combinations tested. Moreover, for rice, IDK in the vials that contained S. oryzae, either alone or in combination with other species, was higher than all the other combinations. Similarly, grain weight was lower in the vials that contained S. oryzae compared to the other species combinations. In general, for S. oryzae and S. zeamais progeny production was increased with the increase of the number of the initial adults that had been placed inside the vials. At the same time, progeny production of all three species was not affected by the presence of another species inside the vial. Given that the coexistence of congeneric species in the same stored product ecosystem is often reported, our results highlight some of the inferences that are necessary in order to predict the potential outcome of competition patterns. Apart from its ecological significance, the prediction of the superior species in mixed species communities, can guide and time any control measures, on a more species-targeted basis.

Walking Responses of Tribolium castaneum (Coleoptera: Tenebrionidae) to Its Aggregation Pheromone and Odors of Wheat Infestations.

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is a worldwide pest of stored grains. Using "Y"-tube olfactometry we studied the response of T. castaneum to odors from simulated wheat infestations containing conspecifics, and infestations containing the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), and the granary weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae). Tribolium castaneum larvae were significantly attracted to odors from all three test species. Tribolium castaneum adults were attracted to grains infested by R. dominica and flour infested by T. castaneum but repelled from grains infested by S. granarius. Further behavioral analysis with pheromones showed that T. castaneum were significantly attracted to their aggregation pheromone, dimethyldecanal (DMD), but not to the R. dominica aggregation pheromone, a mixture of dominicalure 1 and 2. Female T. castaneum adults were attracted to ∼50-fold less DMD than larvae and 100-fold less than male adults, suggesting they are more sensitive to DMD. This study improves our understanding of T. castaneum behaviors to infested grain volatile compounds and pheromones, and may help develop new control methods for grain pest species.

Delivering Beauveria bassiana with electrostatic powder for the control of stored-product beetles.

The efficacy of a Beauveria bassiana-based formulation (Bb38) with Entostat, an electrostatically charged powder, was investigated as a surface treatment against Cryptolestes ferrugineus, Oryzaephilus surinamensis and Sitophilus granarius adults. In lab bioassays, the efficacy of Bb38 against the aforementioned species was examined on concrete, plywood, steel and ceramic, whereas its residual efficacy against the same species was assessed on concrete and steel in the presence or absence of illumination. Finally, the efficacy of Bb38 against O. surinamensis and S. granarius adults was assessed in a commercial grain storage facility under realistic field conditions. In the lab trials, O. surinamensis and C. ferrugineus were much more susceptible to Bb38 than S. granarius on all types of surfaces. Moreover, Bb38 was, at least for O. surinamensis and C. ferrugineus, as effective as the chemical standard (deltamethrin) for at least 2 months after the application, regardless of the presence or absence of illumination. Finally, in the field trial Bb38 provided a satisfactory level of control against O. surinamensis. Bb38 is an effective surface treatment, but its efficacy varies according to the target species, the type of surface and the time post-application. This is the first published report that examines the efficacy of Bb38 as a surface treatment for wider uses in empty warehouses and related storage facilities. © 2017 Society of Chemical Industry.

Preservation of bread-made museum collections by coating technology

Abstract Bread-made artifacts are the products of an ancient creative tradition in some parts of Sardinia. While early objects were intended for pagan events (e.g., grain harvest), later artworks were specifically made for Catholic celebrations, such as Christmas and Easter. Unfortunately, the cultural heritage linked to these objects is endangered by Sitophilus granarius (L.), a tiny insect that causes irreparable damage, such as ruptures and galleries through an intense boring action. In this work, we have evaluated the potential for the coating technology to protect bread-made artifacts from entomatic attack. Within this scope, a nanocomposite coating and an active coating were prepared, and the coated objects were characterized in terms of optical, mechanical, and insect-resistant properties. Overall, the deposition of the coating did not negatively impact the appearance of the objects, although some differences were detected instrumentally in terms of color and gloss. In addition, both coating formulations decreased the Young's modulus of the samples subjected to a flexural test, which was attributed to the plasticizing effect of the poly-methyl methacrylate and deltamethrin. The entomatic tests revealed that the nanocomposite coating was the most effective for preventing the wheat weevil attack, with no damages detected on the samples and high mortality of the insects due to hunger. The approach proposed here could be successfully extended to other art objects (e.g., museum collections) susceptible to insect attacks.

Effect of some botanical oils on the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae)

Six botanical oils of clove, Tugenia aromatica, anise, Pimpinella anisum, chamomile, Matricaria recutita, cumin, Cuminum cyminum, basil, Ocimum basilicum and lupine, Lupinus albus were tested to determine their insecticidal properties against Sitophilus granarius on wheat grains. Considering the percentage of mortality, the toxicity of oils increased gradually with increasing concentrations. Anise oil had the lowest LC50 followed by clove ˂ basil ˂ chamomile ˂ cumin ˂ lupine. Mortality rates of adult weevils was high at the initial time up to 6 weeks post exposure to grains pre-treated with the tested botanical oils at LC50 Level. Thereafter, the activity gradually decreased over time. Both LC50 and LC99 of anise oil prevented weevilsÂ’ oviposition on treated wheat grains. At both LC50 and LC99 values, no adults emerged from eggs laid on grains pretreated with clove and chamomile. At LC50, very few adults emerged from eggs laid on grains pretreated with cumin, lupine and basil in comparison with the control. In addition, the effects of these oils on water absorption and seed germination of treated wheat grains stored for up to 18 weeks was studied. In general, either LC50 or LC99 values of tested oils showed negligible reduction in water swelling capacity (WSC) of treated wheat seeds at the initial time or even after long time of storage. The results also showed negligible decrease in germination of wheat grains treated with tested oils at LC50 and LC99 levels even 18 weeks post-treatment. This study suggests that the use of these botanical oils, especially anise oil, may be effective to protect wheat seeds from stored grain pests in storage.