Comparative insecticidal activity of different plant materials from six common plant species against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is one of the major insect pests of stored grains. Due to export legislation and zero-tolerance for live insect in trade commodities, extensive use of synthetic insecticides is in practice in order to eliminate pest infestations from the lots. Currently, the one and only acceptable chemical to be used in stored grain is phosphine but due to its excessive usage the stored grain pests are becoming resistant against it. Hence discovery of alternative compounds is much needed. In this study we have compared insecticidal efficacy of different plant materials from six commonly grown plants of Pakistan, viz. Allium sativum (Alliaceae), Zingiber officinale (Zingiberaceae), Cymbopogon citratus (Poaceae), Eucalyptus globulus (Myrtaceae), Nicotiana tabacum (Solanaceae), and Azadirachta indica (Meliaceae) against T. castaneum infesting stored wheat, rice, corn and gram pulse. Various plant parts were dried, powdered, and used as admixtures to the stored commodities in the experiments. The results have suggested that A. sativum (garlic) and Z. officinale (ginger) were more effective resulting into 15 times higher adult mortality and 4 to 5 times reduction in grain weight losses when mixed with rice grains. Similarly, A. indica when admixture with wheat checked the population growth in the resources resulting into 3.5 times less adult production compared to controls. A subsequent experiment was conducted to study the dose response of neem seed powder against the beetle pest infesting milled products. Surprisingly, better control was observed either at lowest (1% w/w) or the highest doses (5% w/w). This finding is of great interest to understand the underlying phenomenon which we assume is the ability of T. castaneum to feed selectively in flour mediums, however, further research on this aspect is required to be investigated. The results of this study support the use of botanicals for stored product pest management.     

Array of Synthetic Oligonucleotides to Generate Unique Multi-Target Artificial Positive Controls and Molecular Probe-Based Discrimination of Liposcelis Species

Several species of the genus Liposcelis are common insect pests that cause serious qualitative and quantitative losses to various stored grains and processed grain products. They also can contaminate foods, transmit pathogenic microorganisms and cause allergies in humans. The common occurrence of multi-species infestations and the fact that it is difficult to identify and discriminate Liposcelis spp. make accurate, rapid detection and discriminatory tools absolutely necessary for confirmation of their identity. In this study, PCR primers and probes specific to different Liposcelis spp. were designed based on nucleotide sequences of the cytochrome oxidase 1 (CO1) gene. Primer sets ObsCo13F/13R, PeaCo15F/14R, BosCO7F/7R, BruCo5F/5R, and DecCo11F/11R were used to specifically detect Liposcelis obscura Broadhead, Liposcelis pearmani Lienhard, Liposcelis bostrychophila Badonnel, Liposcelis brunnea Motschulsky and Liposcelis decolor (Pearman) in multiplex endpoint PCRs, which amplified products of 438-, 351-, 191-, 140-, and 87-bp, respectively. In multiplex TaqMan qPCR assays, orange, yellow, red, crimson and green channels corresponding to reporter dyes 6-ROXN, HEX, Cy5, Quasar705 and 6-FAM specifically detected L. obscura, L. brunnea, L. bostrychophila, L. pearmani and L. decolor, respectively. All developed primer and probe sets allowed specific amplification of corresponding targeted Liposcelis species. The development of multiplex endpoint PCR and multiplex TaqMan qPCR will greatly facilitate psocid identification and their management. The use of APCs will streamline and standardize PCR assays. APC will also provide the opportunity to have all positive controls in a single tube, which reduces maintenance cost and labor, but increases the accuracy and reliability of the assays. These novel methods from our study will have applications in pest management, biosecurity, quarantine, food safety, and routine diagnostics.     

储粮环境挥发性化合物与储粮害虫的关系研究进展

每种粮食的储粮环境中都存在有其特征性挥发物,储粮害虫的发生对储粮环境中挥发物具有重要影响。本文简述了顶空式固相微萃取法、浸入式固相微萃取法、电子鼻检测法等储粮挥发物的提取方法及其优缺点,对小麦 Triticum aestivum L.、稻谷 Olyza sativa L.、玉米 Zea mays L.和燕麦 Avena sativa L.等主要储藏粮食种类的挥发性化合物成分、粮食挥发物对昆虫行为反应的影响、主要储粮害虫(赤拟谷盗 Tribolium castaneum、锈赤扁谷盗 Cryptolestes ferrugineus 和象虫 Sitophilus spp.)发生与粮食挥发物的关系等研究进展进行综述,探讨了储粮环境挥发性化合物与储粮害虫关系未来的研究方向,以期对今后储粮害虫生态防治研究与应用提供参考信息。     

Management of Sitotroga cerealella in stored cereal grains: a review

The economic loss due to pest attack in stored commodities is a serious problem worldwide. About 200 insect species attack stored commodities. These insect pests are responsible for quantitative and qualitative losses in cereal grains. Among the stored grain pests, Angoumois grain moth, Sitotroga cerealella is considered as common, top of the list and most destructive pest of cereal grains. Its infestation starts in the standing crop and continues in storage. Although there are many control strategies, our need is some effective, cheap and readily available strategy for safe storage. This review presents different ways by which S. cerealella can be controlled. In this paper, a list of approaches is given which are used to improve the protection of stored grains against S. cerealella attack. These approaches include use of edible oils, containers, synthetic chemicals, agricultural waste materials, plant derivatives, bacterial protoxins, biopesticides, biocontrol enhancers and semiochemicals. If these tactics are followed as combined strategies in a compatible manner, they can provide us an integrated pest management programme for the efficient control of S. cerealella in cereal grains.     

RNAi in the cereal weevil Sitophilus spp: Systemic gene knockdown in the bacteriome tissue

Background  

The weevils Sitophilus spp. are among the most important cosmopolitan pests of stored cereal grains. However, their biology and physiology are poorly understood, mainly because the insect developmental stages take place within cereal grains and because of the lack of gene specific molecular manipulation.     

Assessment of maize and beans storage insect pest in major grain markets,Morogoro-Tanzania

Post-harvest losses for maize and beans are common storage challenges affecting Tanzania's smallholder and large-scale farmers' storage facilities. Consequently, this leads to a reduction of over 50% of harvested grain qualitatively and quantitively per year. Therefore, this experimental study was conducted at the entomological laboratory of the Sokoine University of Agriculture Tanzania, where the research was aimed to assess different common storage insect pests of beans and maize at Morogoro major markets (i.e., Kihonda, Mazimbu and Morogoro Central Market) with similar storage conditions in Morogoro municipality. The complete block design (CBD) with three experimental replications was used. Where locations (Kihonda, Mazimbu and Central market) markets were considered as experimental treatments. The results obtained show that there were no significant differences in number of insect pests (such as maize weevils and bean bruchids) identified between the Kihonda and Central markets (P > 0.05). However, there is a significant difference (P< 0.05) between Mazimbu and other markets regarding the number of insect pest multiplication resulting from the storage condition of those grains in a particular market. Nevertheless, continuous winnowing of stored grains was observed to significantly intensify the infestation of the storage pest in maize and common beans. Therefore, alternatively, to reduce insect pest infestation to maize and common beans in storage facilities, it is important to avoid constant winnowing of stored grains.     

Analysis of the chemical composition of root essential oil from Indian sarsaparilla (Hemidesmus indicus) and its application as an ecofriendly insecticide and pharmacological agent

The Indian sarsaparilla (Hemidesmus indicus) is a commonly used plant in Indian traditional medicine of Ayurveda for the preparation of various non-alcoholic beverages. However, limited studies are available on the essential oil of H. indicus roots (HRO); therefore, the study evaluated the antioxidant, anti-inflammatory and antidiabetic activities of H. indicus root essential oil as well as insecticide potential against the common pests of stored food materials (Sitophilus oryzae, Callosobruchus maculatus and Tribolium castaneum). The repellant efficacy of HRO was found to be high against S. oryzae (8.21 ± 0.55 μg/mL). Likewise, the fumigant potential was also observed for HRO against these pests; the higher activities were observed against S. oryzae and C. maculatus (32.46 ± 1.42 and 35.18 ± 1.62 μg/L). Besides, the essential oil was also found to be active as a contact poison, however, against all the three pests, the toxicity was above 100 μg/mm³, being the highest against C. maculatus (122.8 ± 3.57 μg/mm³). To analyze the possible effect of the essential oil on grains, the different grains were allowed to germinate and compared to that of normal; thus, the non-toxic nature of HRO against the stored products is also confirmed. The essential oil shown to have DPPH hydrogen peroxide and ABTS radical scavenging, nitric oxide scavenging potential, and inhibition of lipoxgenase, alpha-amylase and alpha-glucosidase. Overall, the present study concludes that the H. indicus may be a suitable repellant and fumigant agent against different pests of stored products and a possible antioxidant, anti-inflammatory, and anti-diabetic agent.     

Behavioural responses of Oryzaephilus surinamensis, Tribolium castaneum and Tribolium confusum to naturally and artificially damaged durum wheat kernels

Observations on behavioural activity involved in the host selection by secondary pests of stored grains, Oryzaephilus surinamensis (Linnaeus), Tribolium castaneum (Herbst) and Tribolium confusum J. du Val, with respect to intact and mechanically or naturally damaged kernels are reported. Our results indicate that the attraction of secondary pests is facilitated by broken grain kernels, which resulted from either mechanical damage during harvesting and/or binning procedures, or the feeding activity of primary insect pests. Insect damaged kernels were more attractive to O. surinamensis, T. castaneum and T. confusum than whole kernels; in addition insect damaged kernels elicit more attractiveness than mechanically split kernels. The damage caused by primary pests, such as Rhyzopertha dominica (Fabricius) and Sitophilus oryzae (Linnaeus), on whole kernels may facilitate colonization by secondary pests, which continue damaging the cereals. O. surinamensis, T. castaneum and T. confusum utilize the grain volatile odours to distinguish whether the grain kernels of the stored cereals are damaged mechanically or by insects.     

The pest termites of South America: taxonomy, distribution and status

Abstract: A total of 77 species of termites have been reported as structural or agricultural pests in South America. These records are reviewed, with indication of the damage they cause, their pest status, distribution and sources of information. Among these, 40 species are reported as structural pests, 53 species as agricultural pests and 15 species as both. However, only 18 species are considered major pests and the status of most of the others is uncertain. Uncertainty about status is much higher among agricultural pests. Specific taxonomic problems are discussed and distribution maps of the main pest genera and species are presented. The most important structural pests are the introduced Coptotermes havilandi and Cryptotermes brevis and the native Nasutitermes corniger. Reticulitermes was introduced into Uruguay and Chile, where it is the only serious pest. The main agricultural pests are Heterotermes spp., Nasutitermes spp., Cornitermes spp., Procornitermes spp. and Syntermes spp., and the most affected crops are sugarcane, upland rice and eucalyptus.     

Mites associated with stored grain commodities in Benin, West Africa

After insects, mites are the major arthropod pests that inhabit stored agricultural products worldwide. To determine the acarofauna that infests cowpea, maize, paddy rice and sorghum in Benin (West Africa), surveys were conducted in some principal markets (Dantokpa, Glazoue and Parakou) of this country. A total of 555 samples of grains and debris were collected in May and September 2011. More than 56 species belonging to 24 mite families were recorded in the four products. These mite species included predators, parasites, fungivorous, phytophagous and other groups whose feeding habits are not well known. The family Cheyletidae was the most prevalent and the most diverse predatory mite family encountered, in which Cheyletus malaccensis Oudemans was the most abundant species. Several families of mite pests and mites responsible for allergies (Acaridae, Glycyphagidae, Pyroglyphidae, Pyemotidae and Saproglyphidae) were also detected. The three most dominant and frequent species were C. malaccensis, Suidasia nesbitti (Hughes) and Suidasia sp. Statistical analysis showed that densities of these three mite species were higher in Parakou than in Glazoue and Dantokpa, on one hand, and higher in debris than in grains, on the other hand. The densities of S. nesbitti and Suidasia sp. decreased significantly during the dry season, whereas C. malaccensis remained stable throughout the two samplings. Of all grains, sorghum was the least infested with mites. This study shows that in Benin mites are present in stored agricultural products to which they cause serious damage, and may cause various allergies to people.     

Efficacy of Chamomile,Sweet Almond and Coconut Oils as Post-harvest Grain Protectants of Stored Wheat against Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae)

The lesser grain borer, Rhyzopertha dominica is a major insect pests of stored grain in the tropics. Vegetable oils (Chamomile, Sweet almond and Coconut) at 2.5, 3.5, 5, 7 and 10 ml/kg were tested against Rhyzopertha dominica (F.) in wheat grain. All bio-assays were conducted at 30C. Treatments with vegetable oils at high dose (10 ml/kg) achieving over 95% control within 24 h of exposure to freshly treated grain. There was a little difference between the three oils in their effect. Persistence of oils in grains were tested at short-term storage time (48, 72 and 96h) and intermediate-term (10, 20 and 30 days) after treatments. The activity of all products decreased with storage period. Seed viability was reduced by the high dose (10 ml/kg) of oils treatments.     

Development of a DNA macroarray for simultaneous detection of multiple foodborne pathogenic bacteria in fresh chicken meat

A DNA macroarray was developed to provide the ability to detect multiple foodborne pathogens in fresh chicken meat. Probes targeted to the 16S rRNA and genus- and species-specific genes, including fimY, ipaH, prfA, and uspA, were selected for the specific detection of Salmonella spp., Shigella spp., Listeria monocytogenes, and Escherichia coli, respectively. The combination of target gene amplification by PCR and a DNA macroarray in our system was able to distinguish all target bacteria from pure cultures with a detection sensitivity of 10⁵ c.f.u. ml^?1. The DNA macroarray was also applied to 10 fresh chicken meat samples. The assay validation demonstrated that by combining the enrichment steps for the target bacteria and the DNA macroarray, all 4 target bacteria could be detected simultaneously from the fresh chicken samples. The sensitivity of L. monocytogenes and Shigella boydii detection in the fresh chicken samples was at least 10 and 3 c.f.u. of the initial contamination in 25 g samples, respectively. The advantages of our developed protocol are high accuracy and time reduction when compared to conventional culture. The macroarray developed in our investigation was cost effective compared to modern oligonucleotide microarray techniques because there was no expensive equipment required for the detection of multiple foodborne pathogens.     

Campylobacter spp. detection in the 21st century: A review of the recent achievements in biosensor development

Campylobacter spp. are an important cause of acute bacterial diseases in humans worldwide. Many bacterial species in the Campylobacter genus are considered harmful and may cause several infectious diseases. Currently, there are no commercial biosensors available to detect Campylobacter spp. in food matrices, and little to no testing has been done in research laboratories with actual food matrices. Biosensors potentially provide a powerful means to detect Campylobacter spp. with the advantages of high sensitivity (low limits of detection with a high signal to noise ratio), high specificity (able to selectively detect the target among several similar targets), real time sensing, and in-site monitoring. This review summarizes the latest research in biosensing technologies for detection of Campylobacter spp. based on a variety of transducers and recognition elements. Finally, a comparison is made among all recently reported biosensors for the detection of Campylobacter spp.     

Inheritance and Characterization of Strong Resistance to Phosphine in Sitophilus oryzae (L.)

Sitophilus oryzae (Linnaeus) is a major pest of stored grain across Southeast Asia and is of increasing concern in other regions due to the advent of strong resistance to phosphine, the fumigant used to protect stored grain from pest insects. We investigated the inheritance of genes controlling resistance to phosphine in a strongly resistant S. oryzae strain (NNSO7525) collected in Australia and find that the trait is autosomally inherited and incompletely recessive with a degree of dominance of -0.66. The strongly resistant strain has an LC50 52 times greater than a susceptible reference strain (LS2) and 9 times greater than a weakly resistant strain (QSO335). Analysis of F2 and backcross progeny indicates that two or more genes are responsible for strong resistance, and that one of these genes, designated So_rph1, not only contributes to strong resistance, but is also responsible for the weak resistance phenotype of strain QSO335. These results demonstrate that the genetic mechanism of phosphine resistance in S. oryzae is similar to that of other stored product insect pests. A unique observation is that a subset of the progeny of an F1 backcross generation are more strongly resistant to phosphine than the parental strongly resistant strain, which may be caused by multiple alleles of one of the resistance genes.     

Characterisation of proteolytic enzymes of Eurygaster integriceps Put. (Sunn bug), a major pest of cereals

Eurygaster integriceps (Sunn pest or Sunn bug) is one of the most significant pests of wheat and is responsible for substantial losses in yield and quality of wheat grain in Europe and Asia. Sunn pest salivary gland-derived proteases and other hydrolases damage grain proteins and starch. Characterisation of protease activities from both Sunn pest salivary glands and Sunn pest-damaged wheat grains revealed a broad range of activities in terms of substrate specificity and diversity of isoelectric point. Neutral and alkaline proteases present in Sunn pest-damaged grains were shown to be capable of hydrolyzing gluten proteins, whilst some proteases were also shown to be active against gelatin. The neutral serine proteases present play the dominant role in degradation of gluten quality. The sensitivity of some proteases to proteinaceous and non-proteinaceous serine proteinase inhibitors was shown, including that of a recombinantly expressed protease. It was found that proteases isolated from Sunn pest salivary glands could be activated by trypsin indicating that they are present as zymogens in vivo. Analysis of individual Sunn pest-damaged grains showed great diversity in the proteases present. This work highlights the challenges of developing proteinase inhibitors to manage Sunn pest damage.     

Solid cultures of thrips-pathogenic fungi Isaria javanica strains for enhanced conidial productivity and thermotolerance

Entomopathogenic fungi have great potential to control agricultural and horticultural insect pests, however optimizing conidial production systems to demonstrate high productivity and stability still needs additional efforts for successful field application and industrialization. Although many virulent entomopathogenic fungal isolates have been viewed as potential candidates in a laboratory environment, very few of the isolates are being used in practice for application in agricultural fields as commercial products. I. javanicus is an entomopathogenic fungus that is parasitic to various diverse coleopteran and lepidopteran insects and thought good candidate as biopesticdes. In this work, the basic characteristics of two entomopathogenic fungi, I. javanica FG340 and Pf04, were investigated in morphological examinations, genetic identification, and virulence against Thrips palmi, and then the feasibility of various grains substrates for conidial production was assessed, particularly focusing on conidial productivity and thermotolerance. Isaria javanica FG340 and Pf04 conidia were solid-cultured on 12 grains for 14?days in a Petri dish. Of the tested Italian millet, perilla seed, millet and barley-based cultures showed high conidial production. The four-grain media yielded >1?×?10⁹ conidia/g of I. javanica FG340 and Pf04. Pf04 strain had enhanced thermotolerance up to 45?°C when cultured on Italian millet. In application, it was easy to make a conidial suspension using the cultured grains, and several surfactants were tested to release the conidia. This work suggests several possible inexpensive grain substrates by which to promote conidial production combined with enhanced stability against exposure to high temperature.     

New Formulations of Ethyl Formate to Control Internal Stages of Sitophilus oryzae

Ethyl formate (EF) was tested in mixtures with natural products (NPs) as a fumigant against the internal stages of Sitophilus oryzae. These novel formulations of EF [EF:NPs = 9.0:1.0, (v/v)] were shown to be chemically stable for 1 month after initial mixing. Therefore, EF acts as a good solvent for various NPs having insecticidal activity. The toxicity of EF alone, and of the various EF formulations, was evaluated on each developmental stage at different concentrations and exposure times. The results show that the effect of EF alone, as compared with the various EF formulations, was similar or lower in the mixed age cultures (MAC) of S. oryzae after 6 hr of exposure. For the pupal stage of S. oryzae, EF + thujone showed increased toxicity (>20%) at both 6 hr of exposure at 67.4 mg/L, as well as at 24 hr of exposure at 37.6 mg/L. Also, EF + thujone, EF + menthone, and EF + carvone showed higher toxicities as compared to EF alone, on the pupal stage of S. oryzae after 24 hr of exposure at 37.6 mg/L. However, we couldn't find significant differences in the formulations in terms of their synergistic effects. The most significant result of this research was the ability to use EF as a solvent for the application of various natural materials as fumigants and/or protectants. Our continuing research is aimed at finding natural product formulations that possess enhanced toxicity with respect to the internal stages of stored grain pests, as well as low mammalian toxicity.     

Characterization of Two Polyketide Synthase Genes Involved in Zearalenone Biosynthesis in Gibberella zeae

Zearalenone, a mycotoxin produced by several Fusarium spp., is most commonly found as a contaminant in stored grain and has chronic estrogenic effects on mammals. Zearalenone is a polyketide derived from the sequential condensation of multiple acetate units by a polyketide synthase (PKS), but the genetics of its biosynthesis are not understood. We cloned two genes, designated ZEA1 and ZEA2, which encode polyketide synthases that participate in the biosynthesis of zearalenone by Gibberella zeae (anamorph Fusarium graminearum). Disruption of either gene resulted in the loss of zearalenone production under inducing conditions. ZEA1 and ZEA2 are transcribed divergently from a common promoter region. Quantitative PCR analysis of both PKS genes and six flanking genes supports the view that the two polyketide synthases make up the core biosynthetic unit for zearalenone biosynthesis. An appreciation of the genetics of zearalenone biosynthesis is needed to understand how zearalenone is synthesized under field conditions that result in the contamination of grain.     

First detection of anti-Besnoitia spp. specific antibodies in horses and donkeys in Italy

Among Apicomplexa protozoa infecting equids, Besnoitia spp., Toxoplasma gondii and Neospora spp. represent important issues from a sanitary and zootechnical viewpoint. However, only scarce epidemiological data are available on the spread of the infections in horses and donkeys in Europe. Therefore, a serosurvey was planned to estimate the prevalence of these Sarcocystidae species in Italian equids. Serum samples from 268 horses and 18 donkeys raised in Italy were collected and serologically analyzed to detect anti-Besnoitia spp., anti-T. gondii and anti-Neospora spp. antibodies: an approach based on an initial screening by in-house ELISA followed by a confirmatory WB was used. Two horses (0.7%) and four donkeys (22.2%), showed antibodies anti-Besnoitia spp. Ten horses (3.7%) resulted positive to T. gondii and one of these (0.4%) was seropositive also to Neospora spp. This is the first detection of anti-Besnoitia spp. specific antibodies in Italian horses and donkeys. The study confirmed the circulation of Besnoitia spp. among equids in Europe. Low prevalence of T. gondii and Neospora spp. in horses raised in Italy was reported. Nevertheless, it is noteworthy to consider that consumption of horse meat could represent a source for human toxoplasmosis.     

Eradication of methicillin-resistant Staphylococcus aureus with an antiseptic soap and nasal mupirocin among colonized patients – an open uncontrolled clinical trial

Resistance to β-lactam antibiotics in enteric Gram-negative bacilli may be difficult to detect using standard methods of either Kirby-Bauer disc diffusion (KBDD) or broth dilution for minimal inhibitory concentration (MIC). This difficulty is due to genetic differences in resistance determinants, differences in levels of gene expression, and variation in spectra of enzymatic activity against the substrate β-lactams used for susceptibility testing. We have examined 95 clinical isolates reportedly susceptible to ceftazidime and ceftriaxone, as originally determined by either KBDD or MIC methods. The organisms studied here were isolated in 2002 from two pediatric hospital centers (Seattle, USA and Shanghai, China). They belong to the inducible β-lactamase producing Gram-negative bacilli, such as Enterobacter spp., Citrobacter spp., Serratia spp., Morganella spp., Providencia spp., and Proteus vulgaris. A Kirby-Bauer disc approximation (KBDA) method identified inducible phenotypes of third-generation cephalosporin resistance in 76% of isolates, which would otherwise be considered susceptible by standard KBDD methods.