Sitophilus Granarius Research Articles

Chemical Composition, Quality Parameters, Exopeptidase and Oxidoreductase Activity Changes During Temporal Development of Wheat Grain Infestation by Sitophilus granarius

Changes in chemical composition, grain quality parameters, oxidoreductase and exopeptidase activities of wheat grains infested by Sitophilus granarius were monitored during 1 year of storage. Significant increase in flour titratable acidity of infested grains occurred by day 90. Subsequently, infestation was followed by decrease of grain hectoliter weight on day 180, decrease of carboxypeptidase activity on day 240, polyphenol oxidase and catalase activities increased and total starch decreased on day 270, while significant changes of total protein content, extractable protein concentration, phenylalanyl-aminopeptidase and Zeleny sedimentation occurred between 300 and 360 days of storage. The data indicate that S. granarius infestation influenced chemical composition, quality parameters, as well as oxidoreductase and exopeptidase activity in wheat grains, but the extent of these changes was mostly detectable at higher levels of grain infestation. Among the examined parameters, flour titratable acidity and carboxypeptidase activity showed potential to be used as early indicators of grain infestation. Practical Applications Granary weevil, S. granarius, is one of the major grain-damaging insects. This primary infester feeds on grains as adult, or on grain endosperm as larvae causing significant economic losses, due to unsuitability of damaged grains for human food production. Although various methods of S. granarius detection in stored grains have been applied worldwide, there is still a need for cheap indicative methods for detecting insect infestation. This study investigating changes in chemical composition, quality parameters, oxidoreductase and exopeptidase activities during temporal development of infestation by S. granarius shows that flour titratable acidity and carboxypeptidase activity could be used as early indicators of wheat grain infestation.

Threshold temperature and heat unit requirements for the development of the granary weevil, Sitophilus granarius (L.)

The objective of the present investigation was to determine the effects of temperature on the granary weevil, Sitophilus granarius L., in the laboratory so that forecasting models based on heat accumulation units could be developed for the pest. Development of S. granarius reared on wheat grains was studied at three constant temperatures (15, 20 and 25 °C) and relative humidity of 70 ± 5%. The developmental time was significantly decreased with the increase in temperature. The developmental threshold temperatures estimated for egg, larva, pupa and from egg to adult were 7.79, 7.31, 14.08 and 9.97 °C, respectively. Based on these thresholds, the developmental stages, respectively, needed 92.75, 393.78, 45.04 and 562.36 day degrees to complete their development. Also, about nine generations were calculated for the pest per year under Assiut prevailing conditions. It seems that temperature of 25 °C is the most favourable developmental temperature.

Lactones 43. New biologically active lactones: β -cyclocitral derivatives

In our previous studies bicyclic γ-lactones with cyclohexane ring exhibited high antifeedant activity against storage pests. The activity was correlated with the type and number of substituents in the cyclohexane ring. One of the most potent group of antifeedant agents was δ-iodo-γ-lactones. We present the synthesis of new bicyclic γ-lactones with the cyclohexane ring containing different halogen atoms. To determine the impact of halogen type on biological activity the lactone without halogen atom was also synthesized. The lactones were tested for their antifeedant activity toward the granary weevil beetle (Sitophilus granarius L.), the khapra beetle (Trogoderma granarium Everts) and the confused flour beetle (Tribolium confusum Du Val.). The results of the tests proved that the highest activity was observed for chlorolactone (7) towards larvae and adults of Tribolium confusum. Antibacterial activity of new lactones was also evaluated. Lactone without halogen atom (8) was active against Staphylococcus aureus and Listeria monocytogenes. Studies on the biological activity of synthesised lactones revealed high selectivity towards insect pests as well as bacterial strains. Only the halolactones exhibited significant antifeedant activity. In contrast, antibacterial activity was shown only by the lactone (8) without halogen.

Effect of gaseous ozone for control of stored product pests at low and high temperature

Gaseous ozone (O3) has shown potential for control of insects in stored grain. A previous laboratory study determined doses of ozone necessary to control freely exposed and internal stages of eleven stored product pest species at 20 °C. In this study the impact of temperature on the effect of ozone was tested on two species of stored product pests: Sitophilus granarius and Plodia interpunctella. Insects were exposed to continuous flows of ozone in doses of approximately 33 ppm for 6 d or approximately 131 ppm for 8 d at low temperatures between 7.3 and 7.9 °C and high temperatures between 29.6 and 31.6 °C, respectively. Results from the previous study conducted at 20 °C were used in the data analysis.The result of the treatments was unaffected by the temperatures used in the study. Treatment with a high dose of ozone for 8 d led to full mortality in all stages of S. granarius and all stages of P. interpunctella except eggs at the high temperature. At the low dose for 6 d some survival was found in both species at all three temperatures. Thus, in the temperature range studied, we could not confirm that the effect of ozone on S. granarius and P. interpunctella is related to temperature.

Effect of Storage and Insect Infestation on the Mineral and Vitamin Contents of Wheat Grain and Flour

The objective of this study was to evaluate how storage and Sitophilus granarius L. infestation affects mineral and vitamin (thiamin and riboflavin) contents of wheat grain and flour obtained from the wheat. Wheat samples were infested with nonsexed S. granarius at a rate of two adults per kilogram, and stored for 6 mo at 30 +/- 1 degrees C and 70 +/- 5% relative humidity. Every 30 d, samples of wheat were collected and evaluated for insect population, mineral, thiamin, and riboflavin contents. Flour milled from these wheat samples was also evaluated for mineral, thiamin, and riboflavin contents. None of the analyses performed on the uninfested wheat and flour samples showed any noticeable change during the storage period. The insect population of the infested wheat samples increased during the storage period. The ratio of the mineral contents to dry matter significantly increased in the infested wheat and flour samples during the infestation period, whereas thiamin and riboflavin contents considerably decreased. The feeding habits of S. granarius and the distribution of minerals and vitamins in the wheat grain caused the changes observed in the levels of these compounds. The effects of infestation were greatest in the latter stages, during which the insect population increased greatly.

Synthesis and antifeedant activity of novel alpha-asarone derivatives against stored-product pests

Alpha-asarone (2,4,5-trimethoxypropenylbenzene) derivatives represent a new series of compounds that possess good antifeedant activity against different stored-product pests. A total of 23 novel alpha-asarone derivatives were synthesised and identified by (1) H NMR, (13) C NMR and IR, and their feeding deterrent activities were tested against Sitophilus granarius L., Trogoderma granarium Ev. and Tribolium confusum Duv. Ten compounds showed strong antifeedant activities. Some of the title compounds displayed very good and broad-spectrum activities against adult and larval Coleoptera. The results indicate that the presence of a double bond in the side chain and three methoxy groups is important for antifeedant activity.

Low-pressure treatment to control food-infesting pests (Tribolium castaneum, Sitophilus granarius) using a vacuum packing machine

Since recently, the food industry has been faced with serious problems regarding pest-infested food commodities and deregistration of many chemical biocides by the EU Biocide Directive. These conditions have created an urgent need for a physical method of protecting food against pests. Therefore, a vacuum packing machine was used for laboratory testing of the effectiveness of vacuum packaging on the mortality of the red flour beetle (Tribolium castaneum) and granary weevil (Sitophilus granarius) at different temperatures and exposure times. There were significant differences in the susceptibility to low pressure (vacuum) between the adult insects of both tested species: T. castaneum was approximately 10 times more susceptible to low pressure than S. granarius. A higher temperature significantly shortens the vacuum exposure time necessary to reach 100% mortality in the tested beetles under a constant low-pressure value (1 kPa). The lethal times (LT<sub>99</sub>) foradult T. castaneum were 15.1 h at 25°C and 30.8 h at 15°C. The lethal times (LT<sub>99</sub>) for adult S. granarius were 160.1 hours at 25°C and 274 h at 15°C.  

Evaluation of susceptibility of Rhyzopertha dominica (F.), Sitophilus granarius (L.) and Cryptolestes ferrugineus (Stephens) to spinosad

In this research, we evaluated the toxicity of different concentrations of spinosad to one-day-old adult of Rhyzopertha dominica (F.), Sitophilus granarius (L.) and Cryptolestes ferrugineus (Stephens). The exposure times were 24, 48 and 72 h in all experiments. In contact tests for R. dominica, the maximum mortality rate was achieved with 500 ppm of spinosad after 72 h exposure. The application of 400 ppm of spinosad after 72 h caused maximum mortality in S. granarius. For contact treatment, the complete control of C. ferrugineus was obtained with 500 ppm spinosad at 72 h exposure time. It is possible to recommend 500 ppm of spinosad for complete control of the tested insects through contact application. Estimated LC50 values of spinosad in 72 h after exposure for adults of R. dominica, S. granarius and C. ferrugineus were 1287, 279 and 53.17 ppm, respectively. The results show that C. ferrugineus is the most susceptible insect to spinosad in these experiments.

Ionic liquids based stored product insect antifeedants

Ionic liquids are effective stored product insect antifeedants. Their activity depends on the type of cation and anion. A group of ionic liquids with inorganic (nitrate, nitrite, hydrogen sulphite, dihydrogen phosphate, thiocyanate, phosphate and tripolyphosphate) and organic (propionate, citrate, sorbate, undecylate, dodecylbenzenesulfonate, acesulfamate and saccharinate) anions was synthesized. Their physicochemical properties, microbial and deterrent activity against Tribolium confusum (larvae and beetles), Sitophilus granarius (beetles) and Trogoderma granarium (larvae) were determined. Ionic liquids with a didecyldimethylammonium cation demonstrated deterrent activity, exceeding the activity of the standard, azadirachtin. The compounds proved to be very effective against pathogenic bacteria and fungi. The appropriate selection of the cation and anion allows the design of economic and effective insect antifeedants. Ionic liquids based insect antifeedants provide novel examples of promising management tools in biorational approaches to stored product pest control.

Możliwość zastosowania zymogramów do detekcji α-amylaz wołka zbożowego (Sitophilus granarius L.) pozostałych na ziarnie po żerowaniu owadów

50 wheat grains of Korweta variety were infested with ten or twenty males of granary weevil and exposed for five or ten days. After that time the beetles were removed, and the extracts from grains were prepared and zymograms were done. Clearing zones observed on zymograms, showed the presence of granary weevil α-amylase in all grain extracts obtained after insects feeding. The obtained revealed that both, hidden grain infestation by the pest, as well as grain contamination with the pest metabolism products were possible to detect using the native electrophoresis with zymograms. Although the intensity of clearing zones was larger when the extracts were obtained from the grain with a greater number of insects feeding for a long time, the relationship between the number of insects, time feeding and α-amylase activity was not clearly shown. The amount of granary weevil α-amylases left on grain by feeding males was related to the time of feeding as well as individual activity of enzyme secreted by the salivary gland. Do 50 ziarniaków pszenicy odmiany Korweta wprowadzano po 10 i 20 samców wołka zbożowego i pozostawiono przez okres 5 i 10 dni. Po tym czasie usuwano owady, a z ziarna przygotowywano ekstrakty i sporządzono zymogramy. Na uzyskanych obrazach stwierdzono przejaśnienia świadczące o obecności α-amylaz wołka zbożowego we wszystkich ekstraktach ziarna, na którym żerował owad. Uzyskane wyniki wykazały, że elektoroforeza natywna z zymogramami, pozwala na wykrycie ukrytego porażenia ziarna, ale również na wskazanie ziarna, w którym nie ma już owadów, jednak pozostają produkty przemiany materii. Zasadniczo intensywność przejaśnień była większa wówczas, gdy ekstrakty były otrzymywane z ziarna, na którym większa ilość owadów żerowała przez dłuższy czas, jednak nie można jednoznacznie wykazać zależności pomiędzy liczbą owadów, czasem żerowania a aktywnością pozostawionej α-amylazy. Ilość α-amylaz pozostawionych na ziarnie przez żerujące samce jest związana zarówno z czasem żerowania owadów, jak i z osobniczą aktywnością enzymu w wydzielinie gruczołów ślinowych.

The Hohenheimer Box – A new way to rear and release Lariophagus distinguendus to control stored product pest insects

To improve the biological control of stored product pests, the present paper reports on the development of a rearing box for parasitoids of pest insects. The box contains breeding substrate and populations of hosts and parasitoids and is placed in storage sites, where parasitoids are released continuously over several months. The box was developed to rear Lariophagus distinguendus (Förster) (Hymenoptera: Pteromalidae) to control the granary weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae). Due to sanitary reasons, the bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae) was chosen as an alternative host. Rearing experiments revealed that the cowpea Vigna unguiculata unguiculata (L.) Walp. is most suitable as host substrate. For the outlet of the rearing device, a wire gauze mesh size of 0.8–1.0mm was found suitable to release wasps while holding back the bean weevils. The size of the starting populations of hosts and parasitoids was determined experimentally in a storage building. An amount of 5ml weevils plus 21–60 adult parasitoids on 2kg of cowpeas produced an average of 56 and 62 wasps per week respectively, from June to September. Wasps reared in the boxes had the same number of offspring on granary weevils as wasps from regular lab-cultures. This study demonstrates the feasibility of a rearing box for parasitoids of stored product pests that releases large numbers of wasps over several months. We consider our study as a guideline for the development of similar rearing boxes also for other parasitoid-pest systems in stored products protection throughout the world.

EFFECTS OF PHOTOPERIOD ON THE BIOLOGY OF THE GRANARY WEEVIL, SITOPHILUS GRANARIUS L. IN THE LABORATORY

The present study investigated the effects of photoperiod on the development of immature stages, oviposition periods and adult longevity of the granary weevil, Sitophilus granarius L. at constant temperature of 27±2C° and 70±5°% R.H. in the laboratory. Statistical analysis proved considerable effect of 16 and 24 hr. photophase on the incubation period of eggs. At complete darkness the shortest larval duration (19.6 days) was observed while the longest one (25.3 days) was shown at 24 hr. photophase. Pupal exposed to continuous light showed the lowest mean pupal period (4.7 days) as compared with 5.4 days for the pupal exposed to 16 hr. light. In addition, the period from egg to adult was markedly influenced by the tested photoperiods. The longest developmental period (40.9 days) was observed under continuous light while the shortest one was recorded at complete darkness. The oviposition periods of adult females decreased by increasing the photophase periods. Adult females kept in complete darkness recorded the longest oviposition period (89.4 days). Meanwhile, the shortest period (84.6 days) was reported for females lived under continuous light. Also, adults exposed to complete darkness lived longer than those lived under continuous illumination, however both sexes lived nearly equal periods at any tested photoperiodic regimes

‘Well, Sextus, what can we do with this?’ The disposal and use of insect-infested grain in Roman Britain

Beetle (Coleoptera) pests of stored products such as the granary weevil may have entered the archaeological record by various routes, including: (1) deliberate dumping, and usually burial, of spoilt grain with the aim of preventing further infestation of grain in storage; (2) the use of infested grain as human and animal food; (3) the incorporation of infested grain and living or dead grain pests into deposits by accident and by reworking. It is suggested that these routes, although outlined specifically for beetle grain pests, can stand as a model for the way other insects and biological remains became incorporated into the archaeological record. It also is suggested that the identification of these different depositional routes depends strongly on taking a multi-proxy (‘indicator group’ or ‘indicator package’) approach to the archaeological and biological record of urban sites.

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 June 2012–31 July 2012

This article documents the addition of 96 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Clarias batrachus, Marmota himalayana, Schizothorax richardsonii, Sitophilus zeamais and Syagrus romanzoffiana. These loci were cross-tested on the following species: Clarias dussumeri, Clarias gariepinus, Heteropneustus fossilis, Sitophilus granarius and Sitophilus oryzae.

Insecticidal effect of spinetoram against six major stored grain insect species

Spinetoram is a novel insecticide that belongs to the spinosyn class of insecticidal chemicals. The efficacy of spinetoram against numerous insect pest species in a variety of field crops has been well demonstrated. However, there are no data available for the effectiveness of spinetoram against stored grain insects. In the present study, we evaluated spinetoram as a grain protectant, against six stored-product Coleoptera. The species tested were: the rice weevil, Sitophilus oryzae, the lesser grain borer, Rhyzopertha dominica, the larger grain borer, Prostephanus truncatus, the confused flour beetle, Tribolium confusum, the granary weevil, Sitophilus granarius and the sawtoothed grain beetle, Oryzaephilus surinamensis. All species were tested at the adult stage, on wheat (or maize in the case of P. truncatus) treated to achieve spinetoram concentrations of 0.01, 0.1, 0.5, 1, 2, 5 and 10 ppm. Mortality was recorded after 1, 2, 7, 14 and 21 d of exposure, and 65 d later the wheat and maize were examined for offspring emergence. Among the species examined, P. truncatus and R. dominica were by far the most susceptible, given that mortality was close to 100% after 7 d on wheat treated or maize with 0.1 ppm of spinetoram. At this concentration, progeny production of P. truncatus and R. dominica was negligible. On the other hand, T. confusum was the least susceptible; mortality reached 95% only at 10 ppm, and only after 14 d of exposure. Similarly, O. surinamensis was of limited susceptibility to spinetoram; mortality reached 95% only after 14 d of exposure on wheat treated with 5 ppm. Nevertheless, offspring emergence of these species was extremely low. For S. granarius and S. oryzae, complete (100%) mortality was recorded after 14 d of exposure, at 0.5 and 1 ppm, respectively. At these concentrations or higher, progeny production was notably reduced. The results of the present study demonstrate that spinetoram is effective as a grain protectant, but its efficacy varies according to the target species, concentration and exposure interval.

Chemical composition and insecticidal properties of Lantana camara L. leaf essential oils from Algeria

Essential oils extracted from Lantana camara were tested for fumigant activity against Sitophilus granarius adults. Composition of L. camara essential oil included large amounts of sesquiterpene hydrocarbons, mainly β-caryophyllene. The bioactivity of the essential oil extracted by hydrodistillation from leaves of L. camara was assessed under laboratory conditions. With fumigation bioassays, essential oils showed different activities on S. granarius. April essential oil, after 24 hours of exposure, exerted the highest activity. Similar results were obtained for February and June essential oils after 48 hours of exposure, although December essential oil showed good fumigant activity after 96 hours of exposure. The persistence of the insecticidal efficiency of the essential oil (remanence tests) against S. granarius adults confirmed that June essential oil was efficient for 2 weeks. Even if laboratory bioassays are only the first step towards the use of essential oils in practical applications, these substances represent a possible alternative to chemical insecticides in some market places.

Insecticidal activity of Hypnum cupressiforme (Bryophyta) against Sitophilus granarius (Coleoptera: Curculionidae)

The moss Hypnum cupressiforme Hedw. is cosmopolitan throughout the world and is one of the most common moss species in Turkey. In the autumn of 2011, moss samples were collected from Şadıman Hill located in Ilgaz Mountain National Park in Turkey. After drying the collected samples at room temperature, the green gametophytes and brownish rhizoid parts of the plant were separated from other contents and ground up before extraction procedure. The contact toxicities of 14 column fractions and 11 flash fractions of H. cupressiforme were evaluated against granary weevil (Sitophilus granarius) adults. The fractions C-10 (70.62%) obtained from column chromatography and F-11 (64.48%) obtained from flash chromatography showed the highest activity. As a result of dose dependent studies carried out on C-10 and F-11, LC50 values were calculated as 44.8 μg/μl and 45.3 μg/μl, respectively. Two other fractions C-3 (29.9%) and F-2 (32.1%) were determined to have an active substance different from fractions C-10 and F-11. The LC50 values of fractions C-3 and F-2 were determined as 81.3 μg/μl and 124.6 μg/μl, respectively.

Efficacy of four essential oils against Sitophilus granarius (L.) adults after short-term exposure

A trial was conducted to assess the fumigant toxicity of the essential oils from Rosmarinus officinalis L., Salvia officinalis L., Lavandula angustifolia Mill. and Mentha balsamea Willd. against the adults of Sitophilus granarius (L.). The relationships between the time after treatment (1, 2, and 3 days), temperature (20, 25, 30, 35, and 40°C), concentrati on of essential oils (2.4 and 7.4 ml/L air) and mortality were investigated. In the experiment, the efficacy of the essential oils at 40°C was 95%, whereas thei r efficacy was considerably lower at lower temperatures (from 12 to 36%). Throughout the experiment, the essential oil of rosemary proved to be the most effective fumigant, causing more than 60% mortality of the granary weevil adults. When applying the essential oil of rosemary, more than 50% mortality in the adults of granary weevil was attained at 35°C ( 89%) and 40°C (99%). A satisfactory efficacy of the other essential oils, common lavender (90%), peppermint (97%) and common sage (94%), was attained only at the highest temperature. The activities of the essential oils were better at higher concentrations (36%) than at lower concentrations (32%). When assessing the effect of the concentration on the adult mortality, we achieved more than 50% efficacy only with rosemary (2.4 ml/L of air, 58%; 7.4 ml/L of air, 63%). The data for the other essential oils ranged between 19% (peppermint, 2.4 ml/L of air) and 34% (common sage, 7.4 ml/L of air). The calculated values for the LC 50 and LC 90 showed that only rosemary produced satisfactory fumigant activity on the adult granary weevils, especially in relation to the temperature. However, the positive efficacy identified in our laboratory experiments needs to be validated under conditions similar to those of the applied conditions, that is, warehouses.

Spectrofluorimetric, spectrophotometric and chemometric analysis of wheat grains infested by Sitophilus granarius

Invisible infestation of wheat grains by Sitophilus granarius during postharvest handling is one of the main problems particularly for small enterprises and farm grain storage facilities due to the lack of cheap and fast methods for early detection of infestation, especially when only a small proportion of grain is infested by larvae. In order to determine whether the spectrofluorimetric, spectrophotometric or chemometric analysis of various extracts of wheat grains infested by S. granarius larvae could be used for detection of infested grain, four different types of extracts: 50 mmol dm−3 Tris–HCl pH 8.9, aqueous iso-propanol (φ = 0.55), methanol, and aqueous trichloroacetic acid (γ = 0.2 mg cm−3), of non-infested and infested wheat grains have been examined for fluorescence properties and UV/VIS spectral characteristics, while the chemometric analysis included determination of protein, reactive amino groups, polyphenols and soluble sugar content. Analysis of extracts revealed significant differences in UV/VIS spectral characteristics, level of reactive amino groups and polyphenol content between infested and non-infested grains. The results obtained indicate that instrumental analysis of spectral characteristics of grain extracts could be used as a method for determination of grain infestation.

Some like it hot, some not: influence of extreme temperatures on Lariophagus distinguendus and Anisopteromalus calandrae

AbstractThe parasitic wasp species Lariophagus distinguendus (Förster) (Hymenoptera: Pteromalidae) and Anisopteromalus calandrae (Howard) (Pteromalidae) are used for inoculation biological control of the granary weevil Sitophilus granarius (L.) (Coleoptera: Curculionidae) in grain stores in Europe. To assess their suitability for biological control under extreme temperatures in winter and summer, we studied the influence of temperatures on their parasitization behaviour under natural fluctuating temperature conditions in the field and under constant temperature conditions in the laboratory. At low temperatures (≤20°C), L. distinguendus showed a higher parasitization rate than A. calandrae. At high temperatures (≥25°C), A. calandrae performed better than L. distinguendus that was negatively affected already at temperatures above 30°C. These findings suggest a temperature‐dependent release of either L. distinguendus or A. calandrae to allow a more efficient application of the wasps in biological control.