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The spread of toxigenic Aspergillus into maize by insects and the subsequent aflatoxin contamination poses a risk to humans and animals and has been investigated in North and South America. To evaluate this effect in an African context, Greenhouse studies were conducted in 2022 to determine the role of sap beetles, Carpophilu s dimidiatus Fabricius, 1792 (Coleoptera: Nitidulidae) and maize weevils, Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae) on infection of maize kernels by Aspergillus flavus Link and the resultant aflatoxin accumulation. To test the beetles' efficacy, treatments were applied on partially opened primary ears at 3 different stages of kernel development (BBCH 75, 83, and 87). The treatments were: (i) distilled water, (ii) water with A. flavus spores, (iii) maize grits, (iv) maize grits with A. flavus spores, (v) C. dimidiatus , (vi) C. dimidiatus with A. flavus spores, (vii) S. zeamais , and (viii) S. zeamais with A. flavus spores. Data on kernel infection, maize rotting, yield, and aflatoxin content in kernels were collected. The highest kernel spoilage and yield loss were recorded for the co-inoculation of S. zeamais and A. flavus spore s , followed by S. zeamais without A. flavus spores, and then C. dimidiatus with the fungal spores. Inoculation of maize at the BBCH 83 growth stage resulted in the highest kernel damage and aflatoxin contamination. S. zeamais and, to a lesser extent, C. dimidiatus effectively spread the A. flavus inoculum into non-wounded ears, resulting in fungal and aflatoxin contamination. The yield loss from S. zeamais - Aspergillus co-inoculation occurred due to the grain rotting and actual feeding of the maize weevils. Thus, insect management is important in reducing pre-harvest contamination of maize with mycotoxigenic fungi and their resultant toxins. [ABSTRACT FROM AUTHOR]

Maize (Zea mays Linnaeus), a prominent cereal crop of Nepal, which suffers significantly from storage pest, particularly maize weevil (Sitophilus zeamais (Motschulsky)), during storage by creating holes and consuming the internal part. Effective management of the pest and reduction grain loss is crucial. To address this problem, a study was conducted at the Nepal Agricultural Research Council in Khumaltar, Lalitpur, from April to August, 2023, evaluating the efficacy of essential oils of Acorus calamus Linnaeus, Cuminum cyminum Linnaeus, and Piper nigrum Linnaeus against S. zeamais. Essential oils were extracted using the Clevenger type steam hydrodistillation method. Concentrations of essential oils (5%, 2.5%, 1.25%, 0.63%, 0.31%, 0.15%) were tested in a two factor completely randomized design (CRD) using oils and doses as the two factor, with four replications and control group. The study assessed lethal concentration, weight loss, and repellence tests in petridishes. Progeny of maize weevils (1-7 days old) were introduced into petridishes having 7mm diameter of Whatman filter paper to evaluate the mortality and repellency effect. The number of insects on both side of the petridish (treated and untreated paper) was counted as part of the repellence test. Mortality in treated grains was observed over a 20 days, and with weight loss measured after 60 days. Results showed significant insecticidal activity, with the median lethal concentration (LC50) of A. calamus oil at 24 and 72 hours calculated as 1.24% and 0.43%, respectively in laboratory bioassay. The LC50 for A. calamus treated maize was 4.70% and 0.70% for 1 and 20 days, respectively, followed by C. cyminum and P. nigrum. Acorus calamus Linnaeus oil demonstrated the highest repellent activity (90.00%) at 5% concentration after 4 hours of treatment. Moreover, maize treated with A. calamus oil showed significantly lower weight loss (0.62%) compared to the control. This study indicated the potential of A. calamus oil for pest control, concerns remain regarding its suitability for feed and food purposes due to associated health risks. These findings underscore the need for further research to explore safer alternatives for pest management in maize storage.

The weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) is the most important pest of stored maize worldwide. Experiments were carried out to evaluate the efficacy of Allophylus africanus P. Beauv (Sapindaceae) leaf extracts and Azadirachta indica A. Juss (Meliaceae) seed oil against S. zeamais under farmer storage conditions at the concentrations of 2.5, 5, 7.5, and 10 g/kg of maize. Each concentration is divided into two sets and wrapped in cotton then placed at two different places in 1 kg bag of maize. Maize bags were placed in 5 L containers and 40 adult insects were released inside and covered with a muslin cloth. Adult mortality, progeny inhibition and damage reduction were assessed. The obtained results showed that these tested extracts caused significant mortality to S. zeamais adults. Mortality % recorded 3.33%, 00.00%, 00.00% and 5.88% with neem oil, the methanol, acetone, and hexane extract of A. africanus at the concentration of 10 g/kg after one day post-infestation. Within 12 days of exposure, at the lowest concentration (2.5 g/kg), neem oil, methanol, acetone, and hexane extract caused 76.92%, 100%, 100% and 100% mortality, respectively. At the concentration of 10 g/kg, all the tested extracts completely inhibited F1 progeny production, respectively. Moreover, these extracts reduced the grain damage and weight losses caused by weevils on maize. Considering the wide availability of A. africanus and neem trees, the application of extracts from both plants could be recommended as phytopesticides against maize weevils under storage conditions. [ABSTRACT FROM AUTHOR]

Anisopteromalus calandrae (Howard) and Theocolax elegans (Westwood) have been recorded as parasitoids of the maize weevil, Sitophilus zeamais (Motschulsky), and were collected from maize (Zea mays L.) in the Huasteca Hidalguense. Both species of parasitoids are new records for Hidalgo, and to our knowledge, this is the first report of the association of T. elegans with S. zeamais in Mexico. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the toxicity of Piper hispidinervum essential oil (PHEO) against 11 Brazilian populations of Sitophilus zeamais (Coleoptera: Curculionidae). The effects of sublethal doses of PHEO on the behavior (walking and flying), respiration, and population growth (ri) of the insect populations were investigated. PHEO toxicity was determined through concentration–mortality bioassays, with mortality curves established using increasing PHEO concentrations ranging from 140.00 to 1000.00 μL kg−1. Behavior was evaluated based on walking distance, walking time, walking speed, walking time proportion, flight height, and flight takeoff success. Respiration was measured via the respiratory rate, while population growth (ri) was assessed through the instantaneous growth rate. All 11 populations of S. zeamais were susceptible to PHEO, showing no signs of resistance. The populations exhibited varying behavioral and physiological responses to sublethal exposure to PHEO, indicating different mitigation strategies. The results confirm that PHEO possesses insecticidal potential for controlling S. zeamais populations. However, the observed behavioral and physiological responses should be considered when establishing control measures in pest management programs for stored products. [ABSTRACT FROM AUTHOR]

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Abstract This study emphasizes the phytochemical study of some locally available botanicals against maize weevils. Nine plant parts were collected from six plant species. The test plant powder (200 g) was suspended sequentially in 600 ml of petroleum ether, chloroform, acetone, methanol, and distilled water for 72 h with frequent agitation. Different concentrations of the crude extracts were applied to maize seeds at rates of 10 ml, 15 ml and 20 ml per 100 g. All treatments with different extracts at different rates of application showed significant differences (p 0.05) among all treatments for the prevention of F1 progeny emergence. In all extracts, Clausena anisata showed 100% inhibition of F1 progeny emergence. All treatments significantly reduced seed weight loss and damage. The treated maize seeds were germinated with an acceptable germination quality. In conclusion, an increased dosage of the extract resulted in significant mortality in maize weevils. The seed extracts of Maesa lanceolata and Croton macrostachyus and Clausena anisata leaf extract were observed to be the most promising botanical in protecting stored maize against maize weevil.

The repellent capacity against Sitophilus zeamais and the in vitro inhibition on AChE of 11 essential oils, isolated from six plants of the northern region of Colombia, were assessed using a modified tunnel-type device and the Ellman colorimetric method, respectively. The results were as follows: (i) the degree of repellency (DR) of the EOs against S. zeamais was 20–68% (2 h) and 28–74% (4 h); (ii) the IC50 values on AChE were 5–36 µg/mL; likewise, the %inh. on AChE (1 µg/cm3 per EO) did not show any effect in 91% of the EO tested; (iii) six EOs (Bursera graveolens—bark, B. graveolens—leaves, B. simaruba—bark, Peperomia pellucida—leaves, Piper holtonii (1b*)—leaves, and P. reticulatum—leaves) exhibited a DR (53–74%) ≥ C+ (chlorpyrifos—61%), while all EOs were less active (8–60-fold) on AChE compared to chlorpyrifos (IC50 of 0.59 µg/mL). Based on the ANOVA/linear regression and multivariate analysis of data, some differences/similarities could be established, as well as identifying the most active EOs (five: B. simaruba—bark, Pep. Pellucida—leaves, P. holtonii (1b*)—leaves, B. graveolens—bark, and B. graveolens—leaves). Finally, these EOs were constituted by spathulenol (24%)/β-selinene (18%)/caryophyllene oxide (10%)—B. simaruba; carotol (44%)/dillapiole (21%)—Pep. pellucida; dillapiole (81% confirmed by 1H-/13C-NMR)—P. holtonii; mint furanone derivative (14%)/mint furanone (14%)—B. graveolens—bark; limonene (17%)/carvone (10%)—B. graveolens—leaves. [ABSTRACT FROM AUTHOR]

Post-harvest insects are among the significant problems in the agricultural sector. The most accessible tools available for managing post-harvest arthropod-pests are fumigants because of the convenience of their applications and fast action in disinfecting. This study aimed to examine the fumigant toxicity of essential oil (EO) against maize weevil and identify the specific fumigants among the major components. The EO was extracted from aerial part of Chrysanthemum parthenium L. using Clevenger apparatus and was tested for fumigant toxicity. GCMS was used to determine the chemical composition of EO. The major components were identified and screened virtually using Auto dock vina 1.2. in PyRx 0.8 platform. Dm AChE PDB ID: 6XYY was used as a target for molecular docking and malathion and pirimiphusmethyl were used as a reference for comparison. From the results of binding affinities, most of the major EO components showed better fumigant activity than the reference fumigants. More specifically 1,6-dioxaspiro[4,4]non-ene, β-farensen, bornyl-tiglate, γ-terpinene, p-cymene, bornylacetate, bornyl-isovalerate, terpinen-4-ol, trans-chrysanthenyl-acetate and α-phellandrene were found to be effective fumigants against maize weevil. The above findings suggest that the EO of the aerial part of C. parthenium can be a potential candidate for the development of novel natural fumigants for stored products. [ABSTRACT FROM AUTHOR]

Simple Summary: Several insects can infest alimentary pasta. Since the olfactory sense in insects plays an important role in locating food sources, the aim of this work was to investigate the responses of adult maize weevils, Sitophilus zeamais, to five commercially available categories of macaroni pasta made from cereals and/or legumes in an olfactometric arena. Maize weevil adults were more attracted to the pasta made of 100% of Triticum durum; the attractiveness strongly decreased when combining T. durum with Cicer arietimun or Lens esculenta. A preferential orientation of adult insects to pasta made of chickpeas or lentils was not observed. These results confirm the importance of volatile compounds in insect orientation towards suitable foods and oviposition substrates and provide useful practical information for the safer prevention of maize weevil pasta infestations. We compared the attractiveness of five commercially available Italian macaroni pastas of different shapes (penne, casarecce, and fusilli) made from cereals and/or legumes [100% Triticum durum; 100% Cicer arietinum; 100% Lens esculenta; 50% Triticum durum + 50% Cicer arietinum; 60% Triticum durum + 40% Lens esculenta] to adults of Sitophilus zeamais (L.). A multiple-choice walking bioassay showed that S. zeamais adults were more attracted to cereal than legume pastas. The modified Flit-Track M2 trap devices baited with pasta made with 100% T. durum captured an average of 61.4% of the adults released into the olfactometric arena after 7 days. Of the insects tested, pasta made with 100% C. arietinum trapped 3.8%, pasta made with 100% L. esculenta trapped 2.7%, pasta made with 50% T. durum + 50% C. arietinum trapped 4.3%, and pasta made with 60% T. durum + 40% L. esculenta trapped 4.2%. When individually compared, 79.6% of S. zeamais adults chose the Triticum durum pasta. Orientation to 100% Cicer pasta or 100% Lens pasta was not observed. In the choice test, only 37% and 25% were attracted to Triticum and Cicer pastas or Triticum and Lens pasta, respectively. Our results confirm that the low attractiveness of legume pasta is mainly due to the lack of attractant stimuli rather than the emission of repellent compounds. From a practical perspective, it is also interesting to note how mixed pasta decreases the risk of S. zeamais infestation. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the toxicity of Piper hispidinervum essential oil (PHEO) against 11 Brazilian populations of Sitophilus zeamais (Coleoptera: Curculionidae). The effects of sublethal doses of PHEO on the behavior (walking and flying), respiration, and population growth (ri) of the insect populations were investigated. PHEO toxicity was determined through concentration–mortality bioassays, with mortality curves established using increasing PHEO concentrations ranging from 140.00 to 1000.00 μL kg−1. Behavior was evaluated based on walking distance, walking time, walking speed, walking time proportion, flight height, and flight takeoff success. Respiration was measured via the respiratory rate, while population growth (ri) was assessed through the instantaneous growth rate. All 11 populations of S. zeamais were susceptible to PHEO, showing no signs of resistance. The populations exhibited varying behavioral and physiological responses to sublethal exposure to PHEO, indicating different mitigation strategies. The results confirm that PHEO possesses insecticidal potential for controlling S. zeamais populations. However, the observed behavioral and physiological responses should be considered when establishing control measures in pest management programs for stored products.

The high environmental toxicity of currently used insecticides and the emergence of resistant insect populations have prompted the search for new agents to control insect pests. In this study, we characterized a saline extract from Annona squamosa L. leaf to determine its chemical constituents and effects on third instar Aedes aegypti L. larvae, Nasutitermes corniger Motsch. workers and soldiers, Sitophilus zeamais Motsch. adults, and Hyalella sp. juveniles. The extract showed a protein concentration of 22.9 mg/mL and included lectins (specific hemagglutinating activity of 21,333.33) and trypsin inhibitors (specific activity of 15.6 U/mg), as well as the secondary metabolites cinnamic acid derivatives, rutin, and chlorogenic acid. The extract killed third instar Ae. aegypti larvae (50 % lethal concentration of 1.9 %, w/v) and increased the permeability of the peritrophic membrane of Ae. aegypti larvae. The extract did not affect the survival of N. corniger workers or soldiers but killed S. zeamais adults with mortality rates of 51.2–63.8 %. A strong deterrent feeding effect was detected, making S. zeamais adults reject an artificial diet containing the extract. Juveniles of the microcrustacean Hyalella sp. were highly sensitive to treatment with the extract at the 50 % lethal concentration for Ae. aegypti. In conclusion, A. squamosa leaf extract kills Ae. aegypti larvae and S. zeamais adults by increasing the peritrophic membrane permeability and exhibiting a strong food deterrent effect, respectively. However, as an insecticide, the extract should be used with caution because of its high non-target toxicity. The effects of A. squamosa leaf extract may be linked to the actions of lectins, trypsin inhibitors, rutin, and chlorogenic acid. [Display omitted] • Annona squamosa leaf extract (AsLE) contains lectins, trypsin inhibitors, rutin and chlorogenic acid. • AsLE killed Aedes aegypti L 3 and increased the permeability of peritrophic membrane. • AsLE killed Sitophilus zeamais by starvation due to high deterrent effect. • Juveniles of the microcrustacean Hyalella sp. were strongly sensitive to AsLE. [ABSTRACT FROM AUTHOR]

Maize weevil (Sitophilus zeamais) (Coleoptera:Curculionidae) is an economic stored grain pest that causes significant damage to various stored products, including maize (Zea mays). In this study, we extracted essential oil from the rhizome of sweet flag (Acorus calamus) (Acorales:Acoraceae) by hydro-distillation and tested insecticidal property of the oil at 7 concentrations (10, 5, 2.5, 1.25, 0.625, 0.3125, 0.15625 and control) against maize weevil (Sitophilus zeamais) at the National Entomology Research Center, Nepal Agricultural Research Council in the year 2020/2021. Three different experiments were conducted: scintillating vial bioassay, repellency test, and exposing weevils to oil treated maize grains. Scintillating vial bioassay showed that higher the concentration of essential oil, lower the time required to cause 50 % maize weevil mortality. Median lethal concentration (LC50) at 3 and 24 h was calculated as 2.29 and 0.16 % of oil concentration in scintillating vial bioassay. When oil is treated to maize grain, LC50 for 10 and 16 days was calculated as 2.77 and 0.23 % of oil concentrations. In the same way, at 10 % concentration maize weevil showed highest repellent activity (98.75 %) as compared to 5, 2.5 and 1.25 % concentrations after 24 h of treatment. Weight loss and grain damage were significantly less in the oil treatments than the control. However, from the perspective of health benefits, Acorus calamus treated maize is still questionable for feed and food purpose. As β asarone has carcinogenic effects at certain level, it needs further residue tests of treated maize to know allowable maximum residue limit (MRL) before consumption as food or feed.

Objective: This study aimed to evaluate the efficacy of Corymbia citriodora, Melaleuca alternifolia (Myrtaceae), Mentha × piperita (Lamiaceae), and Schinus terebinthifolius (Anacardiaceae) essential oils as an alternative to manage Sitophilus zeamais (Coleoptera: Curculionidae) adults. Methods: Acute contact toxicity, acute toxicity on treated maize grain, fumigation toxicity, repellency bioassays, and GC-MS analysis of the essential oils were carried out. Results: Corymbia citriodora, M. alternifolia, M. × piperita, and S. terebinthifolius oils were toxic at different levels to S. zeamais through residual contact, ingestion and via fumigation, and were also repellent to adults of this pest. Melaleuca alternifolia oil was the most active in contact (LC50 = 18.98 μL.mL−1), ingestion (LC50 = 1.03 μL.g−1), and fumigant (LC50 = 20.05 μL.L−1 air) bioassays. Citronelal (53.6% in C. citriodora), terpinen-4-ol (46.9% in M. alternifolia), menthol (44.8% in M. × piperita), and β -caryophyllene (16.2% in S terebinthifolius) are the major constituents of these oils. Conclusions: Melaleuca alternifolia and M. × piperita essential oils can be used by residual contact, while those of C. citriodora, M. alternifolia, and M. × piperita by mixing with maize grains. Melaleuca alternifolia essential oil can be used as a fumigant, while those of C. citriodora and S. terebinthifolius as repellents for S. zeamais adults. [ABSTRACT FROM AUTHOR]

Warehouse pests cause losses in seed quality by physically damaging seeds, carrying other pathogens, and leaving residues of their consumption or their remains. Taking into account that warehouse pests have higher metabolism rates than seeds, in the present study, the viability of Sitophilus zeamais (Motschulsky & V.de, 1855) insects and the germination of corn seeds were evaluated for 93 and 180 days, respectively, under conditions of a partial vacuum (0.26 atm (atmosphere)), hermetic sealing, and air exchange. The partial vacuum environment (0.26 atm) did not negatively affect the germination of the seeds over a period of 180 days and resulted in the mortality of adult insects from the 4th day onwards; it also completely prevented physical damage to the seeds. The hermetic packaging did not negatively affect germination, but the insects remained active until day 34, and there was severe damage to the seeds used for their sustenance. Similarly, the gas exchange packaging did not affect germination, but the insects remained active until the last day of observation (93) and also caused severe damage to the seeds used for their maintenance. Partial vacuum (0.26 atm) storage represents a practical solution in certain conditions, for example, the short-term (6 months) storage of germplasms at room temperature (24–26 °C); it can also be useful in the storage and transfer of grains, with the possibility of eliminating or reducing the need for insecticide applications. [ABSTRACT FROM AUTHOR]

Researches on the use of essential oil of Piper aduncum L. (EOPA) as a synergist in stored grain pests are still incipient. This study aimed to determine the toxicity of deltamethrin and EOPA, as well as to study the effect of the binary mixture of EOPA + deltamethrin, on five Sitophilus zeamais Brazilian populations. The toxicity was investigated based on concentration-mortality data from deltamethrin and EOPA in thirteen S. zeamais populations. The standard susceptibility population of ¼ LC20was used with the deltamethrin combinations to generate lethal concentrations capable of causing 50 and 95 % of mortality (LC50and LC95). A binary mixture of EOPA x deltamethrin was also tested in five S. zeamais populations to detect the synergistic effect with the deltamethrin. The concentration-mortality curves were generated, and the residual toxicity values after 24 h of exposure ranged 0.003-0.08 μL cm-2 for deltamethrin, 0.04-2.038 μL cm-2 for EOPA and 0.0016-0.014 μL cm-2 for the binary mixture. The S. zeamais populations showed an uneven toxicity in response to the deltamethrin. The Jacarezinho (Paraná state) population showed resistance, with toxicity ratios for LC50increasing by 3.06 and 4.13 times, when compared to susceptible populations, for EOPA and deltamethrin, respectively. The Barbacena (Minas Gerais state) population was considered as the susceptibility standard in the EOPA toxicity bioassays. The binary mixture suppressed the resistance mechanism of the tested S. zeamais populations due to the synergistic action of the bioinsecticide with the deltamethrin.

One of the most polyphagous pests encountered in maize crops is Tanymecus dilaticollis Gyll. which, are consuming the plants foliage in the first phenophases of vegetation and reduce the crop density. Between 2018 and 2021, the series of research carried out in the Center of Moldova concerning the T. dillaticollis Gyll. pest continued and consisted in monitoring the insect attack produced at: (I) maize sown in different sowing timing and (II) different Romanian and foreign maize genotypes. The maize seeds were treated with systemic insecticide from the neonicotinoid class (imidacloprid 600 g/l) according to the disclaimers received year after year from the Ministry of Agriculture in Romania. In the experimented period, the lowest degree of attack was recorded in the late sowing time, at the beginning of May and in mid-May compared to the optimal sowing time, and the most affected by the attack of hibernating adults was the maize sown early. Regarding the attack produced in Romanian and foreign maize genotypes, it was found five of the hybrids experimented registered attack below the average experience. The results show that sowing time and maize genotype have a smaller role as opposed to spring weather conditions which are influencing the attack size and adult density in the maize crop. [ABSTRACT FROM AUTHOR]

Sitophilus oryzae (L.) and S. zeamais (Motschulsky) are the two main species under the genus Sitophilus that occur mainly on storage grains in tropical and subtropical regions. Both species are pests of economic importance and have morphological resemblance with each other. Identification of these two closely related species of Sitophilus was done based on their morphological characteristics and mitochondrial COI genes. Morphological characters included pronotal punctures and adult genitalia, which showed significant differences. Adult morphometrics also revealed significant variations in the length and width of both male and female weevils. The body length and width of S. oryzae were 2.61 × 0.77 mm (male) and 3.04 × 0.86 mm (female), respectively. Whereas, in S. zeamais the values were 3.41 × 1.03 mm and 3.86 × 1.11 mm. The molecular analysis using Cox1 gene also confirmed the morphological identification and taxonomic status of the species in phylogenetic trees. [ABSTRACT FROM AUTHOR]

According to the United Nations (UN), the global population may skyrocket to 9.8 billion people in 2050 and 11.2 billion in 2100, placing an overwhelming burden on food security as the world will have to meet this growing demand. Maize is the largest staple grain crop produced in developing countries. The maize weevil, Sitophilus zeamais, is one of the most destructive post-harvest pests of stored cereals and grains. The maize weevil contributes up to 40% of total food-grain losses during storage, mainly in developing countries. Current synthetic pesticides are ineffective, and, moreover, they raise serious environmental safety concerns as well as consumer health hazards. Drawing from past oversights and current environmental realities and projections, the global population has been switching to green living by developing sustainable strategies. In our context, these new greener strategies include the utilization of medicinal plants to control maize weevil infestation, which unlocks unlimited innovative possibilities, and, thus, improves the yield, quality, and safety of maize. Medicinal plants are less toxic, easily biodegradable, and capable of protecting grain from pests. This paper systematically outlines the literature on host plants as well as the feeding and associated diseases of the maize weevil. In light of this, we cement medicinal plants as excellent candidates in the pursuit of greener, sustainable, more potent, and cost-effective pesticides. [ABSTRACT FROM AUTHOR]

Two insecticides (deltamethrin and pirimiphos-methyl) were evaluated in laboratory assays as grain protectants when applied as a total percentage of a maize mass to control adult Prostephanus truncatus and Sitophilus zeamais. All experiments were conducted at the University of Thessaly in Greece at 30°C and 65% RH under continuous darkness. Either insecticide was applied to 20 g of maize placed in a vial or to the upper one half, one fourth, or one-eighth layer of the maize, then insects were either added to the vials before or after the maize in a completely randomized block design CRBD with n = 9 replicates. Mortality, progeny production, and insect damaged kernels (IDK) were then evaluated for each vial. Insect introduction method (before or after) did not have any impact on any of the variables. Mortality was nearly 100% for all treatments for both insecticides for P. truncatus. Subsequently, progeny production and the number of insect damaged kernels were very low or zero for P. truncatus. Mortality of S. zeamais remained low across layer treatments for deltamethrin. However, S. zeamais was easily controlled by pirimiphos-methyl. The results of this laboratory study show that while deltamethrin and pirimiphos-methyl have some effectiveness as a layer treatment on a column of maize, efficacy will be dependent on the target species, and the depth of the treated layer, as well as the location on which the insects are present. [ABSTRACT FROM AUTHOR]

The maize weevil, Sitophilus zeamais, is a worldwide pest that disproportionately affects subsistence farmers in developing countries. Damage from this pest threatens food security in these communities as widely available and effective control methods are lacking. With advances over the last decade in the development of genetic pest management techniques, addressing pest issues at the ecosystem level as opposed to the farm level may be a possibility. However, pest species selected for genetic management techniques require a well-characterized genome and few genomic tools have been developed for S. zeamais. Here, we have measured the genome size and developed the first genetic linkage map for this species. The genome size was determined using flow cytometry as 682 Mb and 674 Mb for females and males, respectively. The linkage map contains 11 linkage groups, which correspond to the 10 autosomes and 1 X-chromosome found in the species and it contains 1,121 SNPs. This linkage map will be useful for assembling a complete genome for S. zeamais. [ABSTRACT FROM AUTHOR]

The repellent capacity against Sitophilus zeamais and the in vitro inhibition on AChE of 11 essential oils, isolated from six plants of the northern region of Colombia, were assessed using a modified tunnel-type device and the Ellman colorimetric method, respectively. The results were as follows: (i) the degree of repellency (DR) of the EOs against S. zeamais was 20–68% (2 h) and 28–74% (4 h); (ii) the IC50 values on AChE were 5–36 µg/mL; likewise, the %inh. on AChE (1 µg/cm3 per EO) did not show any effect in 91% of the EO tested; (iii) six EOs (Bursera graveolens—bark, B. graveolens—leaves, B. simaruba—bark, Peperomia pellucida—leaves, Piper holtonii (1b*)—leaves, and P. reticulatum—leaves) exhibited a DR (53–74%) ≥ C+ (chlorpyrifos—61%), while all EOs were less active (8–60-fold) on AChE compared to chlorpyrifos (IC50 of 0.59 µg/mL). Based on the ANOVA/linear regression and multivariate analysis of data, some differences/similarities could be established, as well as identifying the most active EOs (five: B. simaruba—bark, Pep. Pellucida—leaves, P. holtonii (1b*)—leaves, B. graveolens—bark, and B. graveolens—leaves). Finally, these EOs were constituted by spathulenol (24%)/β-selinene (18%)/caryophyllene oxide (10%)—B. simaruba; carotol (44%)/dillapiole (21%)—Pep. pellucida; dillapiole (81% confirmed by 1H-/13C-NMR)—P. holtonii; mint furanone derivative (14%)/mint furanone (14%)—B. graveolens—bark; limonene (17%)/carvone (10%)—B. graveolens—leaves.

We compared the attractiveness of five commercially available Italian macaroni pastas of different shapes (penne, casarecce, and fusilli) made from cereals and/or legumes [100% Triticum durum; 100% Cicer arietinum; 100% Lens esculenta; 50% Triticum durum + 50% Cicer arietinum; 60% Triticum durum + 40% Lens esculenta] to adults of Sitophilus zeamais (L.). A multiple-choice walking bioassay showed that S. zeamais adults were more attracted to cereal than legume pastas. The modified Flit-Track M2 trap devices baited with pasta made with 100% T. durum captured an average of 61.4% of the adults released into the olfactometric arena after 7 days. Of the insects tested, pasta made with 100% C. arietinum trapped 3.8%, pasta made with 100% L. esculenta trapped 2.7%, pasta made with 50% T. durum + 50% C. arietinum trapped 4.3%, and pasta made with 60% T. durum + 40% L. esculenta trapped 4.2%. When individually compared, 79.6% of S. zeamais adults chose the Triticum durum pasta. Orientation to 100% Cicer pasta or 100% Lens pasta was not observed. In the choice test, only 37% and 25% were attracted to Triticum and Cicer pastas or Triticum and Lens pasta, respectively. Our results confirm that the low attractiveness of legume pasta is mainly due to the lack of attractant stimuli rather than the emission of repellent compounds. From a practical perspective, it is also interesting to note how mixed pasta decreases the risk of S. zeamais infestation.

The maize weevil, Sitophilus zeamais, is a worldwide pest that disproportionately affects subsistence farmers in developing countries. Damage from this pest threatens food security in these communities as widely available and effective control methods are lacking. With advances over the last decade in the development of genetic pest management techniques, addressing pest issues at the ecosystem level as opposed to the farm level may be a possibility. However, pest species selected for genetic management techniques require a well-characterized genome and few genomic tools have been developed for S. zeamais. Here, we have measured the genome size and developed the first genetic linkage map for this species. The genome size was determined using flow cytometry as 682 Mb and 674 Mb for females and males, respectively. The linkage map contains 11 linkage groups, which correspond to the 10 autosomes and 1 X-chromosome found in the species and it contains 1,121 SNPs. This linkage map will be useful for assembling a complete genome for S. zeamais.

Simple Summary: Sitophilus zeamais (Motschulsky) is one of the most destructive pests of stored maize grains worldwide. Synthetical chemical insecticides are applied for its control, but these can cause the development of resistant populations and have environmental implications. Essential oils can be a viable alternative to synthetic chemical insecticides, but their long-term effectiveness is still up for debate. The aim of this work was to evaluate the effectivity of Clove bud and Pennyroyal essential oils for long-term (twenty weeks) protection of maize, delivered with the aid of an innovative macro-encapsulation device. The blend of both compounds reduced losses by more than 45%, diminishing the survivability of S. zeamais by over 90%. This work demonstrates the potential application of this technology and solutions on the control of S. zeamais, describing and evaluating their effects on S. zeamais populations and their relation to the damages and losses of maize grains. Maize grains represent a significant contribution for assuring food safety all over the globe. Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), also known as the maize weevil, is one of the most destructive pests in stored maize, causing qualitative and quantitative losses. To control S. zeamais populations in maize storage sites, synthetical chemical insecticides are applied. However, these are often used wastefully, have environmental implications, and can induce the development of resistant populations. In this work, the insecticidal and grain protecting efficacy of an innovative macro-capsule delivery device, loaded with essential oils from Clove bud and Pennyroyal, as well as their combined solutions, was tested against naturally S. zeamais-infested maize grains. The blend of both compounds incorporated in a controlled release device reduced losses by more than 45% over a long storage period of twenty weeks, diminishing the survivability of maize weevils by over 90%. The usage of the blend at a concentration of 370   μ L ⋅ L air − 1 with an antioxidant showed the best results, however, by halving the concentration (185   μ L ⋅ L air − 1) , a significant control of S. zeamais populations was still achieved. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Entomología is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Agricultural Research in the Tropics / Pesquisa Agropecuária Tropical is the property of Pesquisa Agropecuaria Tropical and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bruchid beetles (Callosobruchus maculatus and Callosobruchus chinensis), and maize weevil (Sitophilus zeamais) are important insect pests during the postharvest period. Botanical insecticide is an alternative solution for controlling these insects, and long pepper (Piper retrofractum) has been reported as having insecticidal potential against general insect pests. Film seed coatings with various concentrations of hexane extracts were made for mung bean (Vigna radiata) and corn (Zea mays) seeds. Insecticidal activities of these treatments were assessed at before and after storage period of six months, and seed germination was also evaluated. The hexane extract was subjected to analysis of the bioactive components by using Gas Chromatography-Mass Spectrometry (GC-MS). Results revealed that the hexane extract presented extreme toxicity to both bruchid beetles higher compared to maize weevil at 24 h with LC50 values of 5.57–6.75 and 58.04 μg⋅cm−2, respectively. Bruchid beetles presented significant response to ethanol, acetone and hexane extracts, whereas maize weevil showed relatively low responsibility. Film seed coating with hexane extract at 1% and 3% concentrations with six-month storage presented high insecticidal activity against bruchid beetles by more than 88% mortality but had low kill rates against maize weevil. The coated mung bean seeds presented non-seed germination effect, whereas high effect was observed on coated corn. Isolation of bioactive components demonstrated that there were 74 compounds, where pentadecane was the main compound. Film seed coating technology for mung bean seed preservation by using 1% hexane extract from long pepper fruit presented to be an extremely effective method to control bruchid beetles without any seed germination effect. It could serve as one of the green insecticides of the future.

Warehouse pests cause losses in seed quality by physically damaging seeds, carrying other pathogens, and leaving residues of their consumption or their remains. Taking into account that warehouse pests have higher metabolism rates than seeds, in the present study, the viability of Sitophilus zeamais (Motschulsky & V.de, 1855) insects and the germination of corn seeds were evaluated for 93 and 180 days, respectively, under conditions of a partial vacuum (0.26 atm (atmosphere)), hermetic sealing, and air exchange. The partial vacuum environment (0.26 atm) did not negatively affect the germination of the seeds over a period of 180 days and resulted in the mortality of adult insects from the 4th day onwards; it also completely prevented physical damage to the seeds. The hermetic packaging did not negatively affect germination, but the insects remained active until day 34, and there was severe damage to the seeds used for their sustenance. Similarly, the gas exchange packaging did not affect germination, but the insects remained active until the last day of observation (93) and also caused severe damage to the seeds used for their maintenance. Partial vacuum (0.26 atm) storage represents a practical solution in certain conditions, for example, the short-term (6 months) storage of germplasms at room temperature (24–26 °C); it can also be useful in the storage and transfer of grains, with the possibility of eliminating or reducing the need for insecticide applications.

Insect infestation of cereal grains during post-harvest storage not only causes significant grain loss, but also reduces grain quality and makes grains more susceptible to mold infection. Synthetic pesticides are banned from being used in organic grain storage setting due to their high toxicity. The main insect damaging stored corn grains is maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). The purpose of this study was to evaluate insect repellency and insecticidal potentials of some generally recognized as safe (GRAS) essential oils (EOs) (including cinnamon, clove, thyme, oregano, and orange terpene oils) at concentrations of 1–20% against the maize weevil using an olfactometer and a simulated fumigation method, respectively. The olfactory tests show that cinnamon oil had the highest repellency (90%) to the weevils among the EOs tested. The insecticidal activity study indicates that maize weevil mortality increased with EO concentration and storage time with cinnamon, clove, and thyme oils being more effective. No weevil death was observed at 1% EOs; weevil mortality was 3.3–36% at 5%, which varied with the type of EO and storage time. At 10% or higher concentrations, all tested EO showed comparable or higher insecticidal activity than pirimiphos methyl-positive control at its recommended concentration (5 mg/kg corn). No significant increase in weevil mortality was observed with further increase in EO concentration, with exceptions of oregano oil and thyme oil. The highest weevil mortality levels were observed at week 7 for 15% cinnamon oil (100%) and eugenol (100%), followed by 20% thyme oil (93%). The study indicates that some EOs have great potential to serve as synthetic insecticide alternatives to protect organic corn grains from maize weevil damage during storage. This is important to food security, safety and environmental health. [ABSTRACT FROM AUTHOR]

Discussion The tested aqueous extracts from plants I S. terebinthifolius i , I L. sericea i , I L. tomentosa i , I L. nervosa i , and I L. longifolia i , proved to be effective against I S. zeamais i in stored maize grains, with regard to their repellency. Keywords: bioinsecticide; aqueous extract; maize weevil; stored grains EN bioinsecticide aqueous extract maize weevil stored grains N.PAG N.PAG 11 09/27/22 20220901 NES 220901 1. This study aimed to determine the effects of botanical extracts of five plant species I Schinus terebinthifolius i , I Ludwigia sericea i , I L. tomentosa i , I L. nervosa i , and I L. longifolia i in reducing offspring emergence and repellency potential of adult insects. The plant species were deposited at the Herbarium of the Federal University of Grande Dourados-UFGD, with the following registration numbers: 6391 I L. tomentosa i , 6389 I L. longifolia i , 6388 I L. sericea i and 6390 I L. nervosa i , 6473 I S. terebinthifolius i . [Extracted from the article]

Abstract Background The use of X-ray irradiation in the control of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) infesting stored maize was tested at 60, 70 and 80 KeV as part of the international concerted efforts to save maize production and enhance food security. Investigations were done in the laboratory at mean temperature and relative humidity of 29.2 °C and 75.7%, respectively using three varieties of maize. The possibility that X-ray irradiation can affect the viability of maize grains when planted after weevil control process was also evaluated in the laboratory. Standard methods were used to achieve the specific objectives, and X-ray machine snap constituted the exposure time for each dose. Results The results revealed 10% mortality of adult weevils after 24 h and 40% mortality after a period of 7 days. The result indicates moderate effect on mortality. Progressive increase in mortality was recorded as dose increased from 60 to 80 KeV. X-ray irradiation at the doses tested did not significantly (P > 0.05) restrict S. zeamais emergence from maize grains and did not also significantly protect grains against damage and flour production. There was no difference in the pattern of daily emergence of new progenies and pattern of accumulated emergence. The relationship between X-ray irradiation doses and weight of emerging progenies require more specific analysis. Absence of significant difference between the viability of irradiated grains and un-irradiated grains strongly suggests that X-ray irradiation did not adversely affect seed viability, and this gives irradiation technique an opportunity of higher acceptability in agriculture. Conclusions We recommend > 80 KeV of X-ray irradiation or its incorporation into integrated pest management system in order to achieve effective post-harvest control of the pest.

According to the United Nations (UN), the global population may skyrocket to 9.8 billion people in 2050 and 11.2 billion in 2100, placing an overwhelming burden on food security as the world will have to meet this growing demand. Maize is the largest staple grain crop produced in developing countries. The maize weevil, Sitophilus zeamais, is one of the most destructive post-harvest pests of stored cereals and grains. The maize weevil contributes up to 40% of total food-grain losses during storage, mainly in developing countries. Current synthetic pesticides are ineffective, and, moreover, they raise serious environmental safety concerns as well as consumer health hazards. Drawing from past oversights and current environmental realities and projections, the global population has been switching to green living by developing sustainable strategies. In our context, these new greener strategies include the utilization of medicinal plants to control maize weevil infestation, which unlocks unlimited innovative possibilities, and, thus, improves the yield, quality, and safety of maize. Medicinal plants are less toxic, easily biodegradable, and capable of protecting grain from pests. This paper systematically outlines the literature on host plants as well as the feeding and associated diseases of the maize weevil. In light of this, we cement medicinal plants as excellent candidates in the pursuit of greener, sustainable, more potent, and cost-effective pesticides.

The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae), continues to threaten maize worldwide, with an endemic range in Mexico, Central and Northern South America, and an exotic range in Sub-Saharan Africa. There was a targeted effort beginning in the 1990s to create maize hybrids in the hope of controlling P. truncatus. Through those efforts, several resistant maize hybrids were developed, which were able to reduce progeny production by P. truncatus. However, where P. truncatus has yet to fully establish, including parts of Europe such as Italy and Greece, existing maize hybrids developed for production in Europe have not been investigated for resistance against P. truncatus. In this study, we sought to compare the fitness of two different strains of P. truncatus , one from the native range in Mexico and the other from the invaded range in Ghana, by investigating the progeny production, number of damaged kernels, and frass production of both strains on three maize hybrids (Pico 1, Hamilton 2, and AGN 672) developed for use in Greece and wider Europe to evaluate susceptibility and/or tolerance to P. truncatus. The Mexico strain of P. truncatus produced more progeny on the Pico 1 than the AGN 672 hybrid, while the Ghana strain did not significantly differ in progeny production among hybrids. All hybrids were susceptible to both strains of P. truncatus. There were no real differences in damaged kernels or frass production between the two strains and across the three maize hybrids. Overall, this study provides a foundation for exploring maize resistance in European cultivars to P. truncatus as a possible new tool. • We compared fitness of two different strains of P. truncatus (Mexico and Ghana) on different maize hybrids. • We found progeny production differed among insect strain and hybrids. • The native P. truncatus (Mexico) fitness was decreased on European hybrids compared to the invasive strain (Ghana). [ABSTRACT FROM AUTHOR]

The maize weevil (Sitophilus zeamais Motschulsky, 1855; Coleoptera, Curculionidae) is one of the most important pests associated with stored grains. It is controlled almost exclusively with synthetic insecticides. Thus, leading to problems such as pollution and resistance development. Hence an alternative is the use of natural compounds such as edible mushrooms derivates. The aim of this research was to assess, under laboratory conditions, the insecticidal and insectistatic effect of a hydroalcoholic extract of Pleurotus ostreatus (Jacq.) P. Kumm. 1871 against adults of S. zeamais. The parameters assessed were contact and fumigant toxicity, repellency, and antifeedant effect. The highest contact toxicity (57.5% mortality) was achieved with 30 mL extract L-1 solvent. No treatment showed repellent effect; the repellency index (RI) values were higher than 1, and the antifeeding activity < 30%. The fumigant effect showed a maximum of 30% mortality with the highest concentration (300 µL L-1 air). The hydroalcoholic extract of P. ostreatus exerts contact toxicity and interferes with insect reproduction or oviposition of Sitophilus zeamais. [ABSTRACT FROM AUTHOR]

Maize weevil (Sitophilus zeamais) is a very destructive pest of stored maize, accounting for about 15 - 25 % of loss, and sometimes 100% in severe infestation. Synthetic pesticide is often the first step of control, which is often costly, scarce, detrimental to the environment and human health. As a result, more environmentally friend options like the use of botanicals are encouraged, in line with the United Nation Sustainable Development Goals. The purpose of this study was to assess how fast to kill and how hazardous are four medicinal plant powders on maize weevil. The study was conducted in June-July, 2020 in the Food Science laboratory of Catholic University of Cameroon, Bamenda. Plant powders of pawpaw Carica papaya seeds, cypress Cupressus macrocarpa leaves, piper Piper nigrum seeds and a control (no-input) were assessed. Mortality was observed every 48 hr for 192 hr (8 days). The data was subjected to survival analysis using SPSS ver. 23. The proportion of Event (mortality) and Censored (no mortality) at varied amongst treatment with Event in piper significantly higher ((X² = 26.2, df = 7, P < 0.001) than Censored, and the reverse was the case for the other treatments. Only the piper treatment had 50% lethal time (LT50) of 144 hr. The Kaplan-Meier survival probability curve of piper had many sharp drops unlike the flat curves for control and pawpaw. Hazard ratios were 0.553, 2.47and 0.819 for pawpaw, piper and cypress, respectively. We proposed the possibility of exploring the angle formed between the line linking both ends of the survival curve and the horizontal line linking the end of the survival curve and the y-axis to assess the degree of hazardousness. The findings of this study revealed that piper powder killed the maize weevil very fast and was also the most hazardous treatment. We strongly recommend the integration of piper seed powder in the management of stored maize in order to prolong the shelve life, and maintain the quality and quantity of stored maize. [ABSTRACT FROM AUTHOR]

Sitophilus zeamais (Coleoptera: Curculionidae) is a common pest in stored corn grains [Zea mays (Poaceae)]. Synthetic insecticides are effective to control S. zeamais; however, they can develop resistant insects and are toxic to humans and animals. Compounds with insecticidal potential from plants are alternatives for pest control. This study identified the chemical composition of Cymbopogon flexuosus (Poaceae) essential oil, its insecticidal and repellency activity against S. zeamais. The major chemical constituent found in the essential oil of C. flexuosus was citral (88%). The data showed that the essential oil of C. flexuosus and citral showed better insecticidal and repellent activity than the commercial insecticide Actellic used as positive control. The 100% mortality of S. zeamais was obtained at doses of 50 and 44 µL of essential oil and citral, respectively. The highest repellent activity was obtained with 40 and 50 µL of essential oil and 35.2 and 44 µL of citral, respectively, and the lowest with commercial insecticide Actellic. The lethal dose (LD50) was 18.10 and 18.95 µL for essential oil and citral, respectively. The lethal time was lower at doses of 44 and 50 µL essential oil and citral, respectively, and higher with the commercial insecticide. The insecticidal and repellent action of the essential C. flexuosus and its major compound confirms the potential of producing new biopesticide for the control of S. zeamais in Integrated Pest Management (IPM) programs in stored grains. [ABSTRACT FROM AUTHOR]

Among the various existing techniques, enzymatic degumming represents a process that is establishing itself as a valid alternative to the more classic chemical processes. Moreover, vegetable oils of various origins have been gaining more consideration as sustainable and affordable protectants for cereals and pulses against the attack of several insect pests. Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) is one of the key pests of cereal crops in the field and in stored and processed cereal products. Based on these highlighted issues, the overall aim of this research was twofold: (i) firstly, the effectiveness of the enzymatic degumming process was evaluated through the use of three different enzymes in order to verify the possible industrial application within the SALOV company as an alternative to the conventional chemical process; (ii) in a second phase, the possible use of the innovative refined oils was explored for sustainable stored grain protection towards S. zeamais. The results obtained confirm the strong possibility of applying the enzymatic process, which is innovative and, in a chemical way, more sustainable than the classical one. Regarding the toxicity towards S. zeamais, the crude peanut oil and the chemically refined peanut oil had lower LC50 values (1.836 and 1.372 g kg−1, respectively) than the oils rectified through enzymatic degumming (LC50 from 2.453 to 4.076 g kg−1), and, therefore, they can be suggested as sustainable stored grain protectants. [ABSTRACT FROM AUTHOR]

Storage pests are pests adapted to living indoors, where their entire life cycle occurs on stored agricultural products. Nowadays, insects within storage facilities are the main problem in the storage process. Storage systems such as silos, warehouses, and containers are perfect habitats for insects that feed on stored food because they are protected from weather extremes, have unrestricted access to large food sources, and can live continuously for long periods of time. The objective of this study was to determine the intensity of damage by granary (Sitophilus granarius L.) and maize (Sitophilus zeamais Motsch.) weevils on field maize and popcorn and their biological potential over 20 weeks of the storage process. During the study, physical properties of maize (weight, hectolitre weight, moisture and sample weight) and changes in population density of weevils were measured. The results showed differential susceptibility of maize hybrids to weevil feeding. No differences were found between weevil species in terms of the damage they caused. Popcorn does not favor weevil feeding, resulting in low grain damage and high mortality rates for both weevil species. In contrast to popcorn, field corn favors both weevil feeding and weevil reproductive potential, ultimately decreasing grain mass and quality and making it unsuitable for human and livestock consumption. More susceptible field maize can be selected for shorter storage time and thus faster delivery to market.

This study evaluated farmers' knowledge, perceptions and insect pest management practices of maize in the northwestern part of Amhara National Regional State, Ethiopia. Data was collected by a validated questionnaire from 108 farmers. The association between the variables was assessed using Chi-square test and Ordinal Logit regression model was used to explain the association between the level of insect pest infestation on maize grain and other socio-economic factors. The results showed that pest attack was a common phenomenon and caused up to 60% grain losses. Maize weevil: Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) and moths Sitotroga cerelala (Olivier) (Lepidoptera: Gelechiidae) were identified as the most common and damaging insects. All farmers are using chemical insecticides (Actellic dust and Phostoxin) extensively to minimize the problem. It is concluded that some efforts have to take in changing in farmers' attitude on the use of chemical pesticide and the knowledge gap identified in using cultural practices to manage maize weevil. [ABSTRACT FROM AUTHOR]

Inspections of warehouses were carried out in the South and Southeast of the Republic of Bulgaria,from September 2019 to February 2020. In the province of Yambol, in Galabinci village, chickpea (Cicer arietinumL), an annual legume was for the first time, found to be damaged by the maize weevilSitophilus zeamais Motsch.This is a new host record, Sitophilus zeamaishas never been recordedfeeding on a leguminous host previously. The species was also foundto attack maize in a warehousein the region of Plovdiv, Trud village. The new data about the distribution of the species in the Republic of Bulgaria are presented.

Two major stored products pests of maize are the Prostephanus truncatus (Horn) (larger grain borer) and Sitophilus zeamais (Motschulsky) (maize weevil). Under climate change, P. truncatus may be expected to shift its distribution northward farther into the United States (US). Thus, there is a critical need to develop diversified chemical control tools in the post-harvest supply chain for these two species. In this study, we investigated the efficacy of a novel insecticide formulation, containing the insect growth regulator, S-methoprene, combined with the pyrethroid, deltamethrin and the synergist piperonyl butoxide (Central Life Science, Schaumberg, IL, US), compared to the existing commercial standard formulation without synergist, and controls at inducing direct mortality and sublethal changes in movement on treated grains as a grain protectant, and on concrete as a surface treatment. Mortality of adults was assessed visually, while movement was tracked with a network camera coupled with Ethovision software that automatically recorded velocity and distance moved by both species, after continuous exposure on treated material for 4–168 h. The novel formulation significantly induced mortality while reducing distance and velocity moved by multiple-fold compared to controls for exposed adults even after relatively brief exposure periods. In fact, the novel formulation was just as effective as the older formulation, but used only a fraction of the active ingredients, thus it may be more cost-effective. Overall, the novel insecticide formulation is a promising tool for controlling S. zeamais and P. truncatus in bulk storage and around other food facilities.

Maize grains represent a significant contribution for assuring food safety all over the globe. Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), also known as the maize weevil, is one of the most destructive pests in stored maize, causing qualitative and quantitative losses. To control S. zeamais populations in maize storage sites, synthetical chemical insecticides are applied. However, these are often used wastefully, have environmental implications, and can induce the development of resistant populations. In this work, the insecticidal and grain protecting efficacy of an innovative macro-capsule delivery device, loaded with essential oils from Clove bud and Pennyroyal, as well as their combined solutions, was tested against naturally S. zeamais-infested maize grains. The blend of both compounds incorporated in a controlled release device reduced losses by more than 45% over a long storage period of twenty weeks, diminishing the survivability of maize weevils by over 90%. The usage of the blend at a concentration of 370 μL⋅Lair−1 with an antioxidant showed the best results, however, by halving the concentration (185 μL⋅Lair−1), a significant control of S. zeamais populations was still achieved.

The maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), is one of the most damaging pests of stored cereals causing severe damage to stored grains. In current investigation, six open pollinated maize varieties viz. JALAL (white), AZAM (white), SADAF (yellow), ZARD LOCAL (yellow), KASHMIRI (yellow) and PAHARI (white) were screened out in the laboratory of Entomology Department, Faculty of Agriculture, Gomal University, Dera Ismail Khan, Pakistan for their relative susceptibility/resistance to maize weevil. The experiment was laid out following completely randomized design (CRD) with 5 replicates. Results revealed that minimum (23.8) days to adult emergence of maize weevil were recorded when it was reared on variety Azam; whereas; maximum (34.2) days were recorded on variety Sadaf. Total number of F1 adults emerged were maximum (91) in Azam while minimum (62) in variety Sadaf. Percent infestation of maize kernels was maximum (39.01%) in Azam while minimum (25.80%) was recorded in variety Sadaf. Percent weight loss was maximum in Azam i.e. 26.12% while minimum percent weight loss (16.88%) was recorded in Sadaf. Maximum longevity (68.4 days) of adult weevils was recorded on Azam while minimum (53.4 days) was recorded on variety Sadaf. All the tested varieties had no significant effect on the sex ratio of emerged weevils. High germination percentage was recorded in Sadaf (90%) whereas; low germination was found in Azam (57%). The grain hardness test indicated that yellow varieties including Sadaf, Zard local and Kashmiri had maximum hardness having 317, 302.33 and 296 N grain hardness, whereas; white varieties i.e. Pahari, Jalal and Azam had minimum values of grain hardness i.e. 264.33, 251.66 and 238.33 Newton. The present work has shown that Azam is the most susceptible variety and should not be stored for longer periods whereas; Sadaf is the resistant variety against maize weevil. [ABSTRACT FROM AUTHOR]

Insect infestation of cereal grains during post-harvest storage not only causes significant grain loss, but also reduces grain quality and makes grains more susceptible to mold infection. Synthetic pesticides are banned from being used in organic grain storage setting due to their high toxicity. The main insect damaging stored corn grains is maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). The purpose of this study was to evaluate insect repellency and insecticidal potentials of some generally recognized as safe (GRAS) essential oils (EOs) (including cinnamon, clove, thyme, oregano, and orange terpene oils) at concentrations of 1–20% against the maize weevil using an olfactometer and a simulated fumigation method, respectively. The olfactory tests show that cinnamon oil had the highest repellency (90%) to the weevils among the EOs tested. The insecticidal activity study indicates that maize weevil mortality increased with EO concentration and storage time with cinnamon, clove, and thyme oils being more effective. No weevil death was observed at 1% EOs; weevil mortality was 3.3–36% at 5%, which varied with the type of EO and storage time. At 10% or higher concentrations, all tested EO showed comparable or higher insecticidal activity than pirimiphos methyl-positive control at its recommended concentration (5 mg/kg corn). No significant increase in weevil mortality was observed with further increase in EO concentration, with exceptions of oregano oil and thyme oil. The highest weevil mortality levels were observed at week 7 for 15% cinnamon oil (100%) and eugenol (100%), followed by 20% thyme oil (93%). The study indicates that some EOs have great potential to serve as synthetic insecticide alternatives to protect organic corn grains from maize weevil damage during storage. This is important to food security, safety and environmental health.

Botanical repellents are, usually, considered safe to control Sitophilus zeamais, the main pest of stored maize, as they do not leave toxic residues in food, in addition to having lower costs than chemical insecticides. The aim of this study was to evaluate the repellency potential and the reduction of emerged offspring of botanical extracts, of Schinus terebinthifolius, Ludwigia sericea, L. tomentosa, L. nervosa, L. longifolia, and use them as botanical insecticides for S. zeamais. For the repellency test, arenas were set up, containing 50 g of maize kernels exposed to aqueous extract, besides a control treatment. At the center of each arena, 100 insects were released. After 48 h, the proportion of insects in the treated grains was determined. To test the effects of the extracts on insect mating and egg-laying, free-choice and no-choice tests were performed. Insects in both tests remained for ten days for mating and egg-laying. After this period, insects were removed to evaluate the offspring emergence. Sixty days after grain infestation, the number of emerged insects was counted. All selected botanical extracts demonstrated repellent action against S. zeamais, even after 48 h of application. The L. nervosa aqueous extract significantly reduced the emergence of S. zeamais.

Background: The use of X-ray irradiation in the control of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) infesting stored maize was tested at 60, 70 and 80 KeV as part of the international concerted efforts to save maize production and enhance food security. Investigations were done in the laboratory at mean temperature and relative humidity of 29.2 °C and 75.7%, respectively using three varieties of maize. The possibility that X-ray irradiation can affect the viability of maize grains when planted after weevil control process was also evaluated in the laboratory. Standard methods were used to achieve the specific objectives, and X-ray machine snap constituted the exposure time for each dose. Results: The results revealed 10% mortality of adult weevils after 24 h and 40% mortality after a period of 7 days. The result indicates moderate effect on mortality. Progressive increase in mortality was recorded as dose increased from 60 to 80 KeV. X-ray irradiation at the doses tested did not significantly (P > 0.05) restrict S. zeamais emergence from maize grains and did not also significantly protect grains against damage and flour production. There was no difference in the pattern of daily emergence of new progenies and pattern of accumulated emergence. The relationship between X-ray irradiation doses and weight of emerging progenies require more specific analysis. Absence of significant difference between the viability of irradiated grains and un-irradiated grains strongly suggests that X-ray irradiation did not adversely affect seed viability, and this gives irradiation technique an opportunity of higher acceptability in agriculture. Conclusions: We recommend > 80 KeV of X-ray irradiation or its incorporation into integrated pest management system in order to achieve effective post-harvest control of the pest. [ABSTRACT FROM AUTHOR]

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Sitophilus zeamais attacks stored corn kernels and is traditionally controlled using synthetic pesticides. However, the frequent use of these toxic compounds leads to environmental and health damage and to the development of resistant insect populations. Essential oils (EOs) represent an alternative to conventional pesticides for pest control. The objective of the present study was to evaluate the effect of the combination of EOs with chlorpyrifos against S. zeamais in order to reduce the effective applied dose of the synthetic insecticide. The most active EOs against S. zeamais were Rosmarinus officinalis, Pimenta racemosa var. ozua and Citrus sinensis. Moreover, all the binary mixtures (1:1 volume of EO/volume of EO) of these EOs (P. racemosa–R. officinalis, P. racemosa–C. sinensis and R. officinalis–C. sinensis) showed a higher fumigant activity and repellency than the individual EOs, with the combinatory index (CI) values of these binary mixtures indicating synergism for fumigant activity. The P. racemosa–C. sinensis–chlorpyrifos (16:1 volume of binary mixtures of EOs/volume of chlorpyrifos) combination had a lower LC95 value compared to the respective binary mixtures of EOs, revealing a synergistic effect. In addition, this combination did not produce phytotoxicity on maize grains. The binary mixture P. racemosa–C. sinensis in combination with chlorpyrifos synergized the effect of the synthetic pesticide without affecting germination of the maize grains. In addition, the use of this mixture (P. racemosa–C. sinensis–chlorpyrifos) decreased the net quantity of the synthetic insecticide, thus making it an interesting alternative for the control of the maize weevil S. zeamais. [ABSTRACT FROM AUTHOR]