Sitophilus Granarius Research Articles

Composition of cuticular lipids in the pteromalid wasp Lariophagus distinguendus is host dependent

The insect cuticle is covered by a thin layer of hydrocarbons not only preventing desiccation but also playing an important role in the sexual communication of several species. In the pteromalid wasp Lariophagus distinguendus, a parasitoid of grain infesting beetles, female cuticular hydrocarbons (CHCs) elicit male courtship behaviour. We analyzed the CHC profiles of male and female L. distinguendus wasps reared on different beetle hosts by coupled gas chromatography- mass spectrometry (GC-MS). Statistical analysis of the data revealed significant differences between strains reared on different hosts, while spatially isolated strains reared on the same host produced similar profiles. CHC profiles of parasitoids reared on Stegobium paniceum were statistically distinguishable from those of wasps reared on all other hosts. A host shift from Sitophilus granarius to S. paniceum resulted in distinguishable CHC profiles of L. distinguendus females after only one generation. Considering the role of CHCs as contact sex pheromones, our data suggest that host shifts in parasitic wasps might lead to reproductive isolation of host races due to the modification of the cuticular semiochemistry.

Efficacy of some plants as a post-harvest protectant against some major stored pests

The toxicity of vapours of the essential oil of Ferula gummosa, Elettaria cardamomum and Salvia officinalis on the adults and larvae of some stored product pests was investigated. The bioassays were carried out in 70 mL vials containing 10 individuals of each insect. The LC50 values of fumigant bioassay after 24 h were calculated. Results indicated that the effect of the essential oil of F.gummosa was stronger than E. cardamomum, S. officinalis on stored pests. Also fumigant toxicity of S. officinalis on Sitophilus oryzae was similar to that of Sitophilus granarius adults. On the other hand, R. officinalis had a good effect on adults of Tribolium castaneum and larvae of Ephestia kuehniella. According to our results and good effect of these compounds, they will be a safe replace for chemical compounds in the future.

The effect of the diatomaceous earth formulation DiatoSec on mortality of granary weevil Sitophilus granarius (Coleoptera: Curculionidae) in grains

The insecticidal efficacy of the diatomaceous earth formulation DiatoSec® (Ediafilt Diatomite Mining and Processing Ltd., Hungary) against the granary weevil, Sitophilus granarius (Coleoptera: Curculionidae), was evaluated on maize and barley grain in laboratory tests. The diatomaceous earth formulation was applied at three doses of 1, 2 and 4 g kg-1of both grain types. Mortality of S. granarius adults was estimated after 24 and 48 h and 7, 14 and 21 d of exposure on treated grain. After the 21 d counts, all the exposed adults were removed and progeny production on treated grains was assessed 45 days later.

Electrophysiological and behavioral activity of (E)-2-hexenal in the granary weevil and its application in food packaging.

The purpose of this work was to develop a biodegradable carrier material to control insect pests in cereal products. To this aim, (E)-2-hexenal was used, being a natural compound with antimicrobial activity that is also commonly adopted as a flavoring agent. Three coating layers of polycaprolactone (PCL) were spread onto the internal side of a paperboard carton, the first being the active coating containing (E)-2-hexenal. The antennal sensitivity of Sitophilus granarius to a broad range of doses of (E)-2-hexenal was first demonstrated. Next, the ability of different concentrations of this compound to disrupt the orientation of adult S. granarius beetles to odors of intact wheat kernels was established in a two-choice pitfall bioassay. In addition, invasion tests were carried out over an 8-week period to highlight the effects of the biobased repellent packaging and their potential persistence. The results demonstrated that during the entire monitoring period, the percentage of S. granarius adults found in cartons coated with (E)-2-hexenal-loaded multilayer PCL was about 10 % of the total number of insects used in the bioassay, very low compared with the respective control samples, thus assessing both the effectiveness and persistence of the repellent system developed. Although the infestation level of treated packages was reduced relative to the infestation levels in the controls, any infestation of food packages is unacceptable to consumers, so further tests are required to determine whether infestation can be completely prevented using (E)-2-hexenal.

Bioactivity of short‐chain aliphatic ketones against adults of the granary weevil, Sitophilus granarius (L.)

The granary weevil, Sitophilus granarius (L.), is one of the most damaging pests of stored grains, causing severe quantitative and qualitative losses. Sustainable control means, alternative to the commonly used fumigants and broad-spectrum contact insecticides, are urgently needed owing to legislative limits, the development of resistant insect strains and increasing consumer demand for safe food. Short-chain aliphatic ketones, known to be emitted by cereal grains and previously identified as repellents to adult granary weevils, were evaluated for their ability to disrupt insect orientation towards wheat grains and as possible natural fumigants. In behavioural bioassays, 2-pentanone, 2-hexanone, 2-heptanone and 2,3-butanedione significantly reduced insect orientation towards odours of wheat grains, with 2-hexanone and 2-heptanone being the most active. In fumigation tests, all compounds were effective in killing weevil adults, but they performed differently according to chemical structure, speed of action and presence of wheat grains. In the presence of grains, the highest fumigant toxicity was shown by 2-pentanone (LC(50) = 8.4 ± 1.0 mg L(-1)) after 24 h exposure, and by 2-pentanone (LC(50) = 4.5 ± 0.3 mg L(-1)), 2-heptanone (LC(50) = 7.1 ± 0.3 mg L(-1) ) and 2-hexanone (LC(50) = 8.1 ± 0.6 mg L(-1)) 1 week after the treatment end. Short-chain aliphatic ketones have potential for applications in IPM programmes for the granary weevil because of their behaviour-altering activity and fumigant toxicity.

Insecticidal effect of diatomaceous earth against Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) and Sitophilus granarius (L.) (Coleoptera: Curculionidae) under laboratory conditions

Laboratory experiments were carried out in order to evaluate the insecticidal effect of diatomaceous earth against adults of Callosobruchus maculatus (F) and Sitophilus granarius (L.), two important stored grain pests in darkness (30°C and 65% relative humidity). Wheat and cowpea were treated with the diatomaceous earth formulation Silicosec® (Biofa, Germany), at five concentrations determined with preliminary tests and compared with untreated wheat and cowpea as control. Dead adults were counted 24, 36 and 48 h later. Results showed that increasing concentration of Silicosec® and days after treatment (DAT) significantly increased the mortality rates of adults to above 90% in both experiments. Regarding LC50 and LC95 values, it was observed that C. maculatus adults are more susceptible to Silicosec® than S. granarius. The results showed that these two pests could be controlled successfully with diatomaceous earth. Key words: Callosobruchus maculatus, diatomaceous earth, Silicosec®, Sitophilus granarius, stored grains, cowpea, wheat, effective concentration.

Survey of Insects Pest Stored and Biological Control of Trogoderma Granarium Everts in Setifian Region (North-East of Algeria)

Cereal grains are the major source of food for humans and most domesticated animals. In many developing countries like Algeria, overall post-harvest losses of cereals and legums of about 10–15% are fairly common. The study was conducted in Setif high plains in the north east of Algeria. The Setif region is one of the important areas for the production of cereal crops. The objective of this work was to survey the insects pests stored in different stored products in Setifian region. Using different methods: manual samples, traps, and probes have been used to determine the presence of insects and manual inspection, sieving, cracking-floatation and Berlese funnels are used at present to detect insects in grain. We recorded seven species (6 Coleoptera: Trogoderma granarium, Tribolium castaneum, Rhyzopertha dominica, Tribolium confusum, Sitophilus granarius, Tenebrio molitor and 1 Lepidoptera: Ephestia kuehnielle). The relative abundance of the different species was discussed. Trogoderma granarium was the dominant species (82,10%) of insect pests recorded from cereals grains. So, biological control on Trogoderma granarium is described. The stored conditions for these species are also discussed.

Insecticidal effect of diatomaceous earth against Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) and Sitophilus granarius (L.) (Coleoptera: Curculionidae) under laboratory conditions

Laboratory experiments were carried out in order to evaluate the insecticidal effect of diatomaceous earth against adults of Callosobruchus maculatus (F.) and Sitophilusgranarius (L.), two important stored grain pests in darkness (30°C and 65% RH). Wheat and cowpea were treated with the diatomaceous earth formulation Silicosec® (Biofa, Germany), at five concentrations determined with preliminary tests and compared with untreated wheat and cowpea as control. Dead adults were counted 24, 36 and 48 h later. Results showed that increasing the concentration of Silicosec® and days after treatment (DAT) significantly increased the mortality rates of adults to above 90% in both experiments. Regarding Lc50 and Lc95 values, it was observed that C. maculatus adults are more susceptible to Silicosec® than S. granarius. The results showed that these two pests could be controlled successfully with diatomaceous earth. Key words: Callosobruchus maculatus, diatomaceous earth, Silicosec®, Sitophilus granarius, stored grains, cowpea, wheat.

Mass loss determination of wheat kernels infested by granary weevil from X-ray images

Mass losses in wheat kernels infested by the granary weevil were determined using soft X-ray imaging. The mass loss strongly depended on the life stage of the pest insect. Hence, determination of the correlation between developmental stage and mass loss may help to decide management strategies and can also be used to determine time and place of infestation. The mass losses were calculated from X-ray images, taken from 20 to 66 days after infestation, using the grey scale. To compare calculated mass loss (CML) with the actual mass loss, wheat kernels were weighed. Interdependence of the mean values of the CML and weighed mass (WM) on infestation time was determined and fitted by linear and polynomial curves. During these studies kernels from the infested sample were assigned to six categories based on the CML and morphological features obtained from the X-ray images. The categories were as follows: sound, small larva, medium larva, large larva, pupae and emerged. Comparison of kernels assigned to categories based on mass with kernels classified by area of grey scale revealed that mass was more reliable in assigning grain to particular classes. The mass index decreased the number of wrongly classified kernels. The polynomial curve for mass loss can be used to give an indication of the time and place of infestation.

Insecticidal Activity of the Essential Oil Isolated from Azilia eryngioides (Pau) Hedge et Lamond Against Two Beetle Pests

A large number of plant essential oils have been used against diverse insect pests since they, unlike conventional pesticides, present no risk to humans and the environment. This study was conducted to determine the toxicity of Azilia eryngioides (Pau) Hedge et Lamond (Apiaceae) essential oil against 1- to 7-d-old Sitophilus granarius (L.) (Curculionidae) and Tribolium castaneum (Herbst) (Tenebrionidae) adults. The essential oil was obtained from aerial parts of the plant using a Clevenger apparatus and analyzed by gas chromatography and mass spectrometry. The major constituents of the oil were a-Pinene and bornyl acetate. Fumigation bioassays revealed that A. eryngioides oil had a strong insecticidal activity on adult test insects that were exposed to 37.03, 74.07, 111.11, and 148.14 iL L-1 to estimate mean lethal time (LT50) values. Mortality increased as concentration and exposure time increased, and reached 100% at the 39-h exposure time and concentrations higher than 111.11 iL L-1. Another experiment was designed to determine the mean lethal concentration at the 24-h exposure time (LC50)-, and these values indicated that S. granarius was more susceptible than T. castaneum. It can be concluded that the essential oil of A. eryngioides has potential against two stored-product pests, S. granarius and T. castaneum.

SUSCEPTIBILITY OF SOME EGYPTIAN WHEAT VARIETIES TO THE INFESTATION WITH THE GRANARY WEEVIL, Sitophilus granarius (L). (COLEOPTERA: CURCULIONIDAE).

The present investigation was carried out to evaluate the relative susceptibility of ten Egyptian wheat varieties to the infestation with the granary weevil, Sitophilus granarius (L). The loss in grain weight and the percentage of infested grains were determined in choice and force infestation tests. The obtained results, either in the choice or non-choice infestation tests, indicated that non of the tested varieties were completely resistant against the attack by the insect pest; but their susceptibility to the infestation varied considerably. Variety Gemmiza 7 was the most susceptible with an average infestation level of 18.33% and a maximum weight loss of 6.41 g/100 g grains. Oppositely, variety Beny-sewif 4 was the least susceptible with an infestation level of 3.00% and minimum weight loss of 1.64 g/100 gm. A significant positive correlation was found between the infestation of grains and weight loss (r= 0.86-0. 95**).

Ethyl formate plus methyl isothiocyanate—a potential liquid fumigant for stored grains

Methyl bromide is being phased out for use on stored commodities, as it is listed as an ozone-depleting substance, and phosphine is the fumigant widely used on grains. However, phosphine resistance occurs worldwide, and phosphine fumigation requires a long exposure period and temperatures of >15 °C. There is an urgent requirement for the development of a fumigant that kills insects quickly and for phosphine resistance management. This paper reports on a new fumigant formulation of 95% ethyl formate plus 5% methyl isothiocyanate as an alternative fumigant for stored grains. The formulation is stable for at least 4 months of storage at 45 °C. A laboratory bioassay with the formulation showed that it controlled all stages of Sitophilus oryzae (L.), Sitophilus granarius (L.), Tribolium castaneum (Herbst), Rhyzopertha dominica (F.), Trogoderma variabile Ballion and Callosobruchus maculatus (Fabricius) in infested wheat, barley, oats and peas at 80 mg L(-1) for 5 days, and in canola at both 40 mg L(-1) for 5 days and 80 mg L(-1) for 2 days at 25±2 °C. After an 8-14 day holding period, residues of ethyl formate and methyl isothiocyanate in wheat, barley, peas and canola were below the experimental permit levels of 1.0 and 0.1 mg kg(-1). However, fumigated oats needed an 18 day holding period. The findings suggest that the ethyl formate plus methyl isothiocyanate formulation has potential as a fumigant for the control of stored-grain insect pests in various commodities.

Insecticidal activity of Tanacetum chiliophyllum (Fisch. & Mey.) var. monocephalum grierson extracts and a new sesquiterpene lactone

Extracts from aerial parts and roots of Tanacetum L. (emend. Briq.) chiliophyllum (Fisch. & Mey.) var. monocephalum Grierson from Turkey were investigated for their DPPH scavenging activity and contact toxicity against Sitophilus granarius. The ethyl acetate extract of aerial parts yielded a new sesquiterpene lactone 1- epi-chiliophyllin ( 1) which is a derivative of the compound chiliophyllin previously isolated from T. chiliophyllum var. heimerlei. Also known compounds; neolupenyl acetate (lup-12-ene-3 β-acetate) ( 2), 4′,5,7-trihydroxy-3′,8-dimethoxyflavone ( 3), 4′,5,7-trihydroxy-8-methoxyflavone ( 4) were isolated together with ( 1). Structures of the compounds were determined by spectral methods including UV, IR, MS and 1D, 2D NMR. Highest contact toxicity against the stored granary products pest S. granarius was observed after 48 h (68.49 ± 0.67%). Highest DPPH scavenging activity observed for ethyl acetate extract of the roots at 10 mg/mL concentration (87.8 ± 0.84%). The DPPH scavenging activities of the pure flavonoids ( 3, 4) at 1 mg/mL concentration were unsignificant ( 3, 16.4 ± 0.16%; 4, 17.6 ± 0.82%) when compared with the positive controls α-tocopherol (91.7 ± 1.07%) and BHT (91.7 ± 0.37%) at the same concentration.

Suitability of Tamarind and Some Selected Crop Seeds for the Survival and Development of Sitophilus Linearis (Herbst) (Coleoptera: Cucurlionidae)

Sitophilus oryzae (L.), Sitophilus zeamais (Mots.) and Sitophilus granarius (L.) are major pests of stored grain, especially on cereals. Sitophilus linearis (Herbst) a congeneric of the afore-listed species was obtained from seeds of a wild plant, Tamarindus indica L. The development of S. linearis on some selected crop seeds as well as tamarind seeds was investigated in the laboratory at 25.3-30.3 °C and 75.0% ± 5.0 RH. One hundred grammes each of heat sterilized maize, rice, sorghum, millet, cowpea and tamarind seeds were infested with 100 unsexed adults of S. linearis and observed to determine the suitability of the different substrates for the development of the weevil. Sitophilus linearis bred and multiplied on the tamarind seeds but not on the selected crop seeds in the laboratory. Mean developmental period on the tamarind seeds was 32 days. The highest number (51) of adults that emerged on the first day of emergence was from cultures set up with one-week old adult insects. The highest mean weight (3.9mg) was also recorded on the cultures set up with one-week old insects. However, both mean number of emerged adults and mean adult weight were not significantly different (P>0.05). A significant difference was recorded in the mean percentage survival period of S. linearis on the different substrates (P<0.05) with the longest survival recorded on tamarind seeds. It can therefore be concluded that Sitophilus linearis, though a member of the family of grain weevils, could not reproduce on the cereal substrates or the cowpea seeds presented to it in the laboratory. If further studies confirm these findings, then Sitophilus linearis may pose no threat to cereal production due to its inability to survive and reproduce on them.

English

&nbsp; This research was carried out to evaluate the suppressive efficacy of entomopathogenic fungi&nbsp;Beauveria bassiana&nbsp;against adults of&nbsp;Callosobruchus maculatus&nbsp;(F.) and&nbsp;Sitophilusgranarius&nbsp;(L.) on stored grains in darkness (27&plusmn;2&deg;C and 65&plusmn;5% RH). The insects were inoculated by following immersion in five aqueous suspensions with concentrations determined with preliminary tests and compared with untreated wheat and cowpea as control. Probit analysis showed that the lowest LT50 values in suspensions with highest concentrations (2.3 &times; 107 conidia ml-1) were 6.63 and 10.45 days for&nbsp;C. maculatus&nbsp;and&nbsp;S. granarius, respectively. On the other hand, the LC50 values on day 9 post-treatment were 3.17 &times; 106 and 6.08 &times; 107 con.ml-1 for&nbsp;C. maculatus&nbsp;and&nbsp;S. granarius, respectively. Comparison of Lc50, LT50 values and mortalities indicated that in both assays,&nbsp;B. bassiana&nbsp;was consistently more virulent for&nbsp;C. maculatus&nbsp;than&nbsp;S. granarius.&nbsp;The overall results showed that these two pests were controlled successfully with entomopathogenic fungi&nbsp;Beauveria bassiana. &nbsp; &nbsp; Key words:&nbsp;Callosobruchus maculatus,&nbsp;Beauveria bassiana, Sitophilus granarius, stored grain.

Chemical composition and insecticidal properties of some aromatic herbs essential oils from Algeria

The biological effects on Sitophilus granarius were evaluated for three aromatic herbs essential oils: Foeniculum vulgare, Rosmarius officinalis and Lippia citriodora. Stored grain pests were currently controlled by chemical pesticides. This control method leads to pollution of the environment and intoxication of consumers. Essential oils of aromatic plants are more considered as good control alternative tools. Filter papers treated with 5, 50 and 500 μl of test oil were placed in the bottom cover of 1 l plastic bottle. The insects, 50 adults per bottle, were exposed for 1–5 days. Cumulative mortalities were determined 24 and 120 h after treatment. All treatments were replicated five times. The components of the essential oils were identified through GC and GC–MS. The identity of the constituents was confirmed and their relative proportions determined. The results indicate that these natural products may find potential application as useful, environmentally safe insect control and crop protectant agents.

A New Light on the Evolution and Propagation of Prehistoric Grain Pests: The World's Oldest Maize Weevils Found in Jomon Potteries, Japan

Three Sitophilus species (S. granarius L., S. oryzae L., and S. zeamais Mots.) are closely related based on DNA analysis of their endosymbionts. All are seed parasites of cereal crops and important economic pest species in stored grain. The Sitophilus species that currently exist, including these three species, are generally believed to be endemic to Asia's forested areas, suggesting that the first infestations of stored grain must have taken place near the forested mountains of southwestern Asia. Previous archaeological data and historical records suggest that the three species may have been diffused by the spread of Neolithic agriculture, but this hypothesis has only been established for granary weevils in European and southwestern Asian archaeological records. There was little archeological evidence for grain pests in East Asia before the discovery of maize weevil impressions in Jomon pottery in 2004 using the “impression replica” method. Our research on Jomon agriculture based on seed and insect impressions in pottery continued to seek additional evidence. In 2010, we discovered older weevil impressions in Jomon pottery dating to ca. 10 500 BP. These specimens are the oldest harmful insects in the world discovered at archaeological sites. Our results provide evidence of harmful insects living in the villages from the Earliest Jomon, when no cereals were cultivated. This suggests we must reconsider previous scenarios for the evolution and propagation of grain pest weevils, especially in eastern Asia. Although details of their biology or the foods they infested remain unclear, we hope future interdisciplinary collaborations among geneticists, entomologists, and archaeologists will provide the missing details.

Fumigant Toxicity of some Essential Oils on Adults of some Stored-Product Pests

Plant materials with insecticidal properties have been traditionally used for generations in some parts of the world. In this study, fumigant toxicity of some essential oils extracted from Rosmarinus officinalis L., Mentha pulegium L., Zataria multiflora, and Citrus sinensis (L.) Osbeck var. hamlin on adults of stored-product pests, including Tribolium castaneum, Sitophilus granarius, Callosobruchus maculatus, and Plodia interpunctella were investigated. Pure essential oils were used in glass vials for the bioassay. LC50 values of Citrus sinensis var. hamlin against T. castaneum, S. granarius, and C. maculatus were 391.28, 367.75, and 223.48 µL L -1 air after 24 h, 362.40, 20.45, and 207.17 µL L -1 air after 48 h, respectively. Furthermore, LC50 values of the fumigant test of C. sinensis and M. pulegium essential oils against S. granarius were 0.038 and 367.75 µL L -1 air after 24 h, 0.025 and 320.45 µL L -1 air after 48 h, respectively. On the other hand, LC50 values of R. officinalis and Z. multiflora on P. interpunctella moths were 0.93 and 1.75 µL L -1 after 24 h. Results showed that among tested essential oils, C. sinensis var. hamlin had good fumigant toxicity on T. castaneum, S. granarius, and C. maculatus. In addition, M. pulegium essential oil was stronger than C. sinensis var. hamlin on S. granarius. Results also indicated that both Z. multiflora and R. officinalis had fumigant toxicity on P. interpunctella adults. In summary, results indicated that these essential oils have good fumigant toxicity on stored-product pests.

GC and GC/MS analyses of the Algerian Lantana camara leaf essential oil: Effect against Sitophilus granarius adults

The bioactivity of the essential oil extracted by hydrodistillation from Lantana camara leaves was assessed under laboratory conditions. The composition of L. camara essential oil included large amounts of sesquiterpene, mainly β-caryophyllene (35.70%) and caryophyllene oxide (10.04%). The tested essential oil showed good fumigant activity within 1week of exposure for all tested doses. Moreover, remanence study confirmed that the oil was efficient during 2weeks.

The Use of Entomopathogenic Fungus, Beauveria bassiana (Bals.) Vuill. in Assays with Storage Grain Beetles

Chemical insecticides have been widely employed for the control of storage grain pests. This has caused such problems as insecticide resistance along with contamination of foodstuffs with chemical residues. Thus, there is a growing interest in using pathogenic control agents as alternative. In this study, the potential of Beauveria bassiana (Bb Weevil™, a commercial product containing 2 ×10 9 conidia g -1 ) was evaluated against adults of Tribolium castaneum , Sitophilus granarius and Oryzaephilus surinamensis . The experiments were carried out at the rates of 0, 250, 500, 750 and 1,000 mg kg -1 and exposure intervals of 5, 10 and 15 days, in 24±2°C and 50±5% r.h. Fifteen 1 kg lots of grain (one lot for each exposure time-rate) were prepared and treated with the appropriate predetermined doses. Four 50 g samples of each were taken as replications and placed in glass vials. Thirty 1-7 day old adults were introduced into each glass vial. Following mortality count in each exposure time, the adults (dead and alive) were removed and the vials left in the same conditions for a further 45 days to have the progeny production assessed. Means were separated by employing Tukeys Test (P= 0.05). All main effects (dose, exposure time and insect species) as well as associated interactions were significant (P< 0.01), with the exception of exposure time×insect, which was not significant. In all the experiments, mortality increased with increase in dose rates and exposure time with the highest mortality being observed after 15 days of exposure to 1,000 mg kg -1 concentration . These amounts were recorded 88.33 ±3.96, 78.31 ±2.15 and 64.99 ±4.4% for S. granarius , O. surinamensis and T. castaneum , respectively. S. granarius was more susceptible than the others, because the highest mortalities in each of the three exposure times and for all dose rates were observed in this species. The lowest LC 50 value within the exposure times was determined 452.855 mg kg -1 after 15 days for S. granarius . Results achieved from progeny indicate significant differences only between rates and insect species. For all species, the highest progeny production was observed in rate 0 mg kg -1 . The results obtained in this research recommend that Bb Weevil™ could be used to control different grain storage pests but to find longer exposure intervals and higher rates are subject to further future research.