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Simple Summary: The current study intends to establish the pest management approach for smallholder maize farmers on storage pests of maize and determine their current control practices. We administered a questionnaire to maize farmers from the Eastern Cape Province of South Africa. The study found that metal tanks are the farmers most preferred storage facility of maize. The results showed that maize was mostly infested by maize weevils and maize grain moths. Farmers reported managing these pests using chemical pesticides. The extensive usage of this pesticide in protecting stored maize could cause human health-related issues and may result in the development of pest resistance. This study aims to establish the pest management approach for pests of stored maize and determine the current control practices. Semi-structured questionnaires were administered to 77 smallholder farmers from 16 villages at King Sabata Dalindyebo local municipality in the Eastern Cape Province of South Africa. The results revealed that about 50% of the farmers had a formal education, the average farm size was 1 hectare, and they were predominantly cultivating yellow maize. Most farmers (57%) cultivated maize for human consumption, income generation, and livestock feeding. The results also showed that metal tanks tended to be the most preferred (81.82%) storage facility for storing maize. Furthermore, the study found that Sitophilus zeamais Motschulsky and Sitotroga cerealella (Olivier) were the major storage insect pests of maize. The storage pests were managed using synthetic pesticides (84.42%), namely aluminium phosphide. This pesticide is a solid formulation for generating gas phosphine for fumigation. The continued indiscriminate use of this pesticide in protecting stored maize in this region could be a health hazard to humans and may result in the development of pest resistance. [ABSTRACT FROM AUTHOR]

Stored maize is frequently attacked by different pests, such as insects and microorganisms. The aim of the present study was to evaluate the bioactivities of sulcatone (6-methyl-5-hepten-2-one) against the maize weevil Sitophilus zeamais and the phytopathogenic fungi Fusarium verticillioides, Aspergillus flavus, and A. parasiticus. Sulcatone showed a strong repellent effect with a maximum value of −92.1 ± 3.2% at 40 µM in two-choice olfactometer bioassays and an LC95 value of 17.2 µL/L air (95% 16.5–18.1) in a fumigant toxicity experiment. The antifungal effect of sulcatone was evaluated through the fumigant method, reporting MIC values of 3.5, 3.8, and 3.9 mM for F. verticillioides, A. parasiticus, and A. flavus, respectively. Additionally, a silo-bag experiment containing all pests was conducted to evaluate the potential use of sulcatone in a real storage system. Sulcatone caused 71.69 ± 1.57% weevil mortality in silo-bags and proved to be effective as a fungicidal and antimycotoxigenic agent since both ergosterol and fumonisin B1 content were significantly reduced by 60% in silo-bags containing sulcatone. This study demonstrated that sulcatone has the potential to be used for the control of both insects and fungi of stored maize, without affecting the germination of grains. [ABSTRACT FROM AUTHOR]

Simple Summary: The house cricket, Acheta domesticus, is one of the species recently authorised for production and commercialisation as novel food by European legislation. Powder from this insect can be used to enrich bread, extruded snacks, and pasta. The aim of this work was to analyse the behavioural response of one of the main pests of alimentary pasta, the maize weevil (Sitophilus zeamais), to different types of semolina pasta enriched or not enriched with increasing proportions of house cricket powder. In five-choice behavioural bioassays, the number of maize weevil adults attracted to 100% durum wheat pasta was significantly higher than those attracted to the other pasta types enriched with house cricket powder. In two-choice behavioural bioassays, all types of pasta had a positive and significant attraction. In similar experiments, cricket powder alone was not attractive, indicating a neutral effect towards insects. These observations suggest that the lower attractiveness of pasta enriched with cricket powder is mainly due to a masking effect of host food odours. The behavioural response of adult maize weevil, Sitophilus zeamais, to different types of semolina pasta enriched or not enriched with increasing proportions (5%, 10%, and 15%) of house cricket (Acheta domesticus) powder was investigated in olfactometer arena bioassays by using trap devices. In the five-choice behavioural bioassays, the number of S. zeamais adults attracted to 100% durum wheat semolina pasta was significantly higher than those attracted to the other pasta types enriched with A. domesticus powder. In the two-choice behavioural bioassays, the Response Index for each pasta type was positive and significant. However, although not significant, there was a progressive reduction in the Response Index as the cricket powder content increased. In similar experiments, there were no significant differences between cricket powder alone and the control in the number of attracted S. zeamais, indicating a neutral effect towards insects. These observations suggest that the lower attractiveness of pasta enriched with house cricket powder is mainly due to the masking of host food odours. Solid-phase microextraction coupled to gas chromatography–mass spectroscopy identified a total of 18 compounds in the head-space samples of the different types of pasta, highlighting differences in volatile composition. Some volatile compounds were only present in the pasta produced with cricket powder. In particular, 1-octen-3-ol and phenol were present in the samples containing 5%, 10%, or 15% cricket powder; pentanal, benzaldehyde, and dimethyl disulphide were present in samples containing 10% or 15% cricket powder; and 2,5-dimethyl-pyrazine was present in the sample containing 15% cricket powder. Further investigation with individual compounds and mixtures is needed to define the chemical basis of the differences in the insect olfactory preference observed in this study. [ABSTRACT FROM AUTHOR]

Abstract The objective of this work was to compare methods of sampling insect pests in wheat (Triticum aestivum) grains stored in bulk. The data were collected in three agricultural seasons (2012, 2016, and 2020), 90 days after phosphine fumigation, in 10 replicates. Three treatments were evaluated: pitfall traps, manual probe, and pneumatic probe. During the entire evaluation period, the manual probe showed an inferior performance in sampling live insect pests. The pneumatic probe is more efficient for the collection of maize weevils (Sitophilus zeamais), and the pitfall trap, for capturing the rusty grain beetle (Cryptolestes ferrugineus).

Abstract The thrust of the study was to determine the chemical composition of the essential oils extracted from Thymus pallescens de Noé and Cymbogon citratus Stapf. as well as to evaluate their efficacy in controlling Sitophilus zeamais Motschulsky and Tribolium castaneum (Herbst) in either single or combined populations. Carvacrol (56.04%) and geraniol (20.86%) were identified as the major constituents of T. pallescens and C. citratus respectively. The tested essential oils showed pronounced insecticidal activity against the pest species in relation with the applied doses. T. pallescens EO had the highest efficacy and S. zeamais was found to be more susceptible to both individual and combined treatments. With reference to the contact and fumigation assessments, T. pallescens EO effectuated corrected mortality rates ranging from 42.5–100% to 25–100% in S. zeamais with corresponding lethal concentration (LC50) values of 17.7 µl/ml and 15µL/L air respectively. Whereas, the T. pallescens EO exhibited corrected mortality rates of 42.5–100% and 20–100% with corresponding LC50 values of 18.1 µl/ml and 15.5 µL/L air against T. castaneum in contact and fumigation assessments, respectively. The corrected mortality rates increased for both insect species when using combination treatments, with significant increases in the LC50 values, ranging from 8.59 to 49.9% for both pest species. Analysis of energy biomarkers in the treated insects indicate significantly increased protein and carbohydrate contents and decreased lipids levels. The study therefore demonstrated the bio-insecticidal toxicity of the EOs from T. pallescens and C. citratus against two important maize post-harvest pests, concurrently revealing significant positive and negative insecticidal activity gradients in relation to single or combined populations.

The thrust of the study was to determine the chemical composition of the essential oils extracted from Thymus pallescens de Noé and Cymbogon citratus Stapf. as well as to evaluate their efficacy in controlling Sitophilus zeamais Motschulsky and Tribolium castaneum (Herbst) in either single or combined populations. Carvacrol (56.04%) and geraniol (20.86%) were identified as the major constituents of T. pallescens and C. citratus respectively. The tested essential oils showed pronounced insecticidal activity against the pest species in relation with the applied doses. T. pallescens EO had the highest efficacy and S. zeamais was found to be more susceptible to both individual and combined treatments. With reference to the contact and fumigation assessments, T. pallescens EO effectuated corrected mortality rates ranging from 42.5–100% to 25–100% in S. zeamais with corresponding lethal concentration (LC50) values of 17.7 µl/ml and 15µL/L air respectively. Whereas, the T. pallescens EO exhibited corrected mortality rates of 42.5–100% and 20–100% with corresponding LC50 values of 18.1 µl/ml and 15.5 µL/L air against T. castaneum in contact and fumigation assessments, respectively. The corrected mortality rates increased for both insect species when using combination treatments, with significant increases in the LC50 values, ranging from 8.59 to 49.9% for both pest species. Analysis of energy biomarkers in the treated insects indicate significantly increased protein and carbohydrate contents and decreased lipids levels. The study therefore demonstrated the bio-insecticidal toxicity of the EOs from T. pallescens and C. citratus against two important maize post-harvest pests, concurrently revealing significant positive and negative insecticidal activity gradients in relation to single or combined populations. [ABSTRACT FROM AUTHOR]

Simple Summary: The two closely related maize and rice weevils exhibit differential host preferences among stored maize, wheat, and paddy grains. The maize weevil adults prefer to select maize, followed by paddy and wheat, while rice weevil adults mainly migrate towards wheat. The 2-ethylhexanol, piperitone, and (+)-Δ-cadiene are the major components in volatiles from both maize and wheat, but the abundance of these chemicals is much lower in maize than in wheat. The volatile limonene was only detected in paddy. The 2-ethylhexanol, piperitone, and (+)-Δ-cadiene were all attractive to both weevils, whereas limonene was attractive only to rice weevils. The different volatile profiles among the grains and the sensitivity of the two pest species towards these volatiles may explain the behavioral differences between maize and rice weevils in selecting host grains. The variance in sensitivity of maize and rice weevils towards host volatile chemicals with abundance differences is likely a determinant driving the two insect species to migrate towards different host grains. The Sitophilus zeamais (maize weevil) and Sitophilus oryzae (rice weevil) are two insect pests that have caused huge economic losses to stored grains worldwide. It is urgent to develop an environmentally friendly strategy for the control of these destructive pests. Here, the olfactory-mediated selection preference of the two weevil species to three stored grains was analyzed, which should help establish a pull–push system in managing them. Bioassays showed that maize weevil adults prefer to select maize, followed by paddy and wheat, while rice weevil adults mainly migrate towards wheat. Volatile analyses revealed that 2-ethylhexanol, piperitone, and (+)-Δ-cadiene are the major components in volatiles from both maize and wheat, but the abundance of these chemicals is much lower in maize than that in wheat. The volatile limonene was only detected in paddy. Y-tube bioassays suggest that 2-ethylhexanol, piperitone, and (+)-Δ-cadiene were all attractive to both weevils, whereas limonene was attractive only to rice weevils. Overall, maize weevil appeared more sensitive to the tested volatiles based on having much lower effective concentrations of these volatiles needed to attract them. The differences in volatile profiles among the grains and the sensitivity of the two species towards these volatiles may explain the behavioral differences between maize and rice weevils in selecting host grains. The differences in sensitivity of maize and rice weevils towards host volatile components with abundance differences are likely determinants driving the two insect species to migrate towards different host grains. [ABSTRACT FROM AUTHOR]

Stored maize is frequently attacked by different pests, such as insects and microorganisms. The aim of the present study was to evaluate the bioactivities of sulcatone (6-methyl-5-hepten-2-one) against the maize weevil Sitophilus zeamais and the phytopathogenic fungi Fusarium verticillioides, Aspergillus flavus, and A. parasiticus. Sulcatone showed a strong repellent effect with a maximum value of −92.1 ± 3.2% at 40 µM in two-choice olfactometer bioassays and an LC95 value of 17.2 µL/L air (95% 16.5–18.1) in a fumigant toxicity experiment. The antifungal effect of sulcatone was evaluated through the fumigant method, reporting MIC values of 3.5, 3.8, and 3.9 mM for F. verticillioides, A. parasiticus, and A. flavus, respectively. Additionally, a silo-bag experiment containing all pests was conducted to evaluate the potential use of sulcatone in a real storage system. Sulcatone caused 71.69 ± 1.57% weevil mortality in silo-bags and proved to be effective as a fungicidal and antimycotoxigenic agent since both ergosterol and fumonisin B1 content were significantly reduced by 60% in silo-bags containing sulcatone. This study demonstrated that sulcatone has the potential to be used for the control of both insects and fungi of stored maize, without affecting the germination of grains.

The repellency of solvent extracts of Calpurnia aurea leaves was evaluated on the maize weevils and the red flour beetles. Nine-cm Whatman number 1 filter paper that is partitioned into treatment, neutral and non-treatment portions was used for the experiment. Each solvent extract treatment was applied at 2.5, 5 and 10% rates. Insects were released in the neutral portion, while the untreated part served as a control. A choice bioassay experimental method that is laid down in a completely randomized design within three replications was used. 5 and 10% rates of the polar solvent extracts of Calpurnia aurea leaves induced significantly (p

Insecticides of synthetic origin used indiscriminately to manage insect pest populations are known for genotoxicity, neurotoxicity and teratogenicity in non-target organisms as well as the development of resistance in target insects. These issues have focused insect pest management research towards the use of plant-based chemicals of a volatile nature. In this study, two plant-origin volatile compounds, carvacrol and menthone have been evaluated for their potential insecticidal properties against the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae). These two natural volatile chemicals repelled adults and caused lethality in adults as well as larvae. These two volatile chemicals inhibited acetylcholine esterase enzyme activity in adults when fumigated with sub-lethal concentrations. Both volatile chemicals reduced oviposition potential, progeny production and feeding behavior as well as prolonged the developmental period of the insect. Therefore, it can be concluded that these two natural volatile chemicals can be used in the preparation of volatile chemical-based formulations in the management of maize weevil S. zeamais. DOI: http://dx.doi.org/10.5281/zenodo.10145014

Insecticides of synthetic origin used indiscriminately to manage insect pest populations are known for genotoxicity, neurotoxicity and teratogenicity in non-target organisms as well as the development of resistance in target insects. These issues have focused insect pest management research towards the use of plantbased chemicals of a volatile nature. In this study, two plant-origin volatile compounds, carvacrol and menthone have been evaluated for their potential insecticidal properties against the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae). These two natural volatile chemicals repelled adults and caused lethality in adults as well as larvae. These two volatile chemicals inhibited acetylcholine esterase enzyme activity in adults when fumigated with sub-lethal concentrations. Both volatile chemicals reduced oviposition potential, progeny production and feeding behavior as well as prolonged the developmental period of the insect. Therefore, it can be concluded that these two natural volatile chemicals can be used in the preparation of volatile chemical-based formulations in the management of maize weevil S. zeamais. [ABSTRACT FROM AUTHOR]

The insecticidal and repellent effect of essential oil isolated from fresh leaves of Porophyllum linaria on maize weevil was evaluated, as well as the effect on the grain germination after treated. In total, 28 constituents were identified by gas chromatography coupled with mass spectrometry accounting for 99.86% of whole essential oil. The main majority compounds were β-myrcene (41.94%), D-limonene (20.29%), and estragole (20.03%). Contact toxicity significantly increased with dose and time after treatment. With the 800 ppm (highest concentration), the mortality (%) obtained for the tenth and fifteenth day was 43 and 82%, respectively, whereas with 50 ppm (lowest concentration) 30% mortality was obtained at the end of the experiment (fifteenth day). At 15 d (end of the experiment), the LC50 y LC90 were obtained with values of 329.01 ± 44.35 y 1058.86 ± 117.76 ppm, respectively. For a concentration of 800 ppm, a selection index of zero was obtained, indicating the preference of the pest to the untreated maize (control). The maize grains germination test showed a significant reduction both in the length of hypocotyl and radicle of maize grain. So, in the highest dose, the hypocotyl and radicle length was 1.40 ± 0.34 and 9.14 ± 0.55 cm, respectively, whereas the control group registered 3.28 ± 0.39 and 13.02 ± 0.97 cm, respectively. This finding is promising since as it could result in the identification of botanical substances capable of suppressing maize weevil, Sitophilus zeamais development. [ABSTRACT FROM AUTHOR]

Sitophilus zeamais causes significant losses to maize produce worldwide. The use of biodegradable and environmentally friendly botanicals as an alternative to synthetic pesticides is increasingly becoming important. Therefore, we sought to determine the use of plant extract formulations to manage S. zeamais during storage. Crude Zanthroxylum usambarense and Warburgia ugandensis stembark extracts were used for contact toxicity and repellent bioassays against S. zeamais. The formulations that exhibited the highest repellence and mortality were tested for insecticidal activity during storage for six months. Phytochemical profiles of the extracts were determined using GC-MS, and molecular docking of active compounds against insect target proteins was done. Mortality analyses revealed LD50 values of 114.89 µg/mL and 197.19 µg/mL for Z. usambarense's hexane and methanol organic extracts, respectively. Warburgia ugandensis extracts had LD50 values of 69.25 µg/mL and 163.52 µg/mL, respectively. Extract formulations achieved weevil perforation index values of <50.00 in all treatments. The docking analysis showed the pesticidal potential of several compounds, and mortality could be attributed to Eugenol (19.28%), 1,8-cineole (5.78%) and Linalool (21.42%). The tested botanicals have demonstrated their ability to suppress S. zeamais development in stored maize and could be utilized to protect maize grains during storage. [ABSTRACT FROM AUTHOR]

Maize weevil is a major pest of stored maize grains in many regions of the world including Nigeria. A laboratory investigation was conducted to assess the potency of Ocimum gratissimum L. leaves for Sitophilus zeamais control. The O. gratissimum powder was used for ethanolic extract preparation by soaking 300 g of dry powdered plant material in 1.5 L of absolute ethanol for 24 hours at room temperature with continuous stirring for 10 minutes. The ethanolic extract tested for phytochemical constituents, including tannins, alkaloids, saponins, phenolic compounds, terpenoids, steroids, glycosides, and flavonoids, showed that they were all present except steroids. Exposure of adult S. zeamais to different concentrations of ethanolic extract generated significant cumulative mortality, and increased as the concentration increased; 35.5%, 64.4%, 95.5%, and 100% mortalities of S. zeamais were recorded at 30, 150, 250, and 750 mg/mL extract, respectively. The capacity of the extract to induce 100% mortality at 750 mg/mL concentration revealed its potential as an insecticidal agent. The powder caused low weight loss and seed damage of grains treated with the highest dosage. The ethanolic extract of O. gratissimum displayed a high level of insecticidal activity against maize weevil suggesting a high possibility of using it as toxicant, repellent, and feeding deterrent in integrated pest management strategies of S. zeamais. [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]

Sitophilus zeamais (maize weevil) is one of the most destructive pests that seriously affects the quantity and quality of wheat (Triticum aestivum L.). However, little is known about the constitutive defense mechanism of wheat kernels against maize weevils. In this study, we obtained a highly resistant variety RIL-116 and a highly susceptible variety after two years of screening. The morphological observations and germination rates of wheat kernels after feeding ad libitum showed that the degree of infection in RIL-116 was far less than that in RIL-72. The combined analysis of metabolome and transcriptome of RIL-116 and RIL-72 wheat kernels revealed differentially accumulated metabolites were mainly enriched in flavonoids biosynthesis-related pathway, followed by glyoxylate and dicarboxylate metabolism, and benzoxazinoid biosynthesis. Several flavonoids metabolites were significantly up-accumulated in resistant variety RIL-116. In addition, the expression of structural genes and transcription factors (TFs) related to flavonoids biosynthesis were up-regulated to varying degrees in RIL-116 than RIL-72. Taken together, these results indicated that the biosynthesis and accumulation of flavonoids contributes the most to wheat kernels defense against maize weevils. This study not only provides insights into the constitutive defense mechanism of wheat kernels against maize weevils, but may also play an important role in the breeding of resistant varieties. [ABSTRACT FROM AUTHOR]

Food security is contingent upon increasing crop yields but also upon reducing crop losses to post-harvest pests and diseases. Weevils are particularly important agents of post-harvest losses in grain crops. A long-term evaluation of a biocontrol agent, Beauveria bassiana Strain MS-8, at a single dose of 2 × 109 conidia kg−1 of grain was formulated in kaolin as a carrier at levels of 1, 2, 3, and 4 g kg−1 of grain and screened against the maize weevil, Sitophilus zeamais. After six months, the application of B. bassiana Strain MS-8 at all levels of kaolin significantly reduced the maize weevil populations compared to the untreated control (UTC). The best control of maize weevil was observed in the first 4 months after application. Strain MS-8 applied in a kaolin level of 1 g kg−1 performed the best, resulting in the lowest number of live weevils (36 insects/500 g of maize grain), the lowest level of grain damage (14.0%), and the least weight loss (7.0%). In the UTC the number of live insects was 340 insects/500 g of maize grain, the level of grain damage was 68.0%, and weight loss was 51.0%. [ABSTRACT FROM AUTHOR]

Microbial enzymes produced using biological processes are of great importance due to their contribution to sustainable solutions for agricultural production. In our previous study, the chitinase enzyme from Lactobacillus coryniformis was purified, immobilized to zinc oxide (ZnO) nanoparticles, and its effectiveness as a bioinsecticide against the storage pest Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae) was determined by forming a nanoformulation. In this study, the effectiveness of immobilized chitinase (nanoformulation), free chitinase, malathion, ZnO, and L. coryniformis on intestinal enzymes such as alkaline phosphatase (ALP), adenosine triphosphatase (ATPase), and lactate dehydrogenase (LDH) were tested to elucidate some of the mechanism of insect death. The effects of the applications on the activity of ALP, ATPase, and LDH enzymes were found to be statistically significant (p < 0.01). The lowest activity in the ALP enzyme was measured in Malathion and 8 mg/L applications. While the lowest activity in the ATPase enzyme was measured in the 8 mg/L application, the lowest activity in the LDH enzyme was observed in the malathion and 6 mg/L applications. Applications caused a decrease in enzyme activities (LDH, ALP, and ATPase). This situation affected the intestinal activities negatively, disrupted the feeding physiology of the insect, and caused its death. Obtained results showed that the formulation created may have an important role in the protection of corn from this pest. [ABSTRACT FROM AUTHOR]

Sitophilus zeamais (Motsch.) (Coleoptera: Curculionidae) has a global distribution and is one of the most important post-harvest pests of maize (Zea mays L.). Some Mexican maize races could be a novel source of resistance against S. zeamais to improve commercial maize, generating lines, varieties, and hybrids with resistance to the pest. These are original races from the center of origin of maize and have been exposed to selection pressure from S. zeamais and other pests for thousands of years, which probably resulted in some type of resistance. We studied the resistance of Mexican maize races to S. zeamais focusing on antixenosis, antibiosis, and tolerance. Antibiosis reduces the survival and reproduction of the insect or prolongs the time between generations, whereas antixenosis reduces the rate of initial and successive accumulation of the insect population. Obligate-antibiosis and free-choice bioassays were performed, and in those experiments, resistance traits and the consumption by S. zeamais were measured. The most resistant accession showed high adult mortality and fewer adults in the 1st generation, where the number of emerged adults is an ideal trait to evaluate the level of maize resistance to the pest. Net consumption (in grams) is the most economically important trait because it indicates the gross amount lost in a store, while yield losses (percentage of consumption) allow for studying tolerance. The type of endosperm did have an influence on the resistance/tolerance to S. zeamais. The flint varieties showed significantly higher mortality of adults before entering the seed, a lower quantity of emerged adults of the first generation in the obligate-antibiosis bioassay, and lower net consumption and percentage in both bioassays. In general, the varieties of the races Cristalino de Chihuahua, Apachito, and Azul showed high levels of resistance, with the Cristalino-079 (flint) and Azul (floury) accessions also being tolerant, and low levels of consumption by S. zeamais. Both could be used in breeding programs to reduce losses caused by S. zeamais. [ABSTRACT FROM AUTHOR]

Studies were carried out to determine the efficacy of three spices (Allium sativum L., Capsicum frutescens L., and Zingiber officinale Rosc.) against Sitophilus zeamais reared on maize grains. Application rates of 0.5, 1.0 and 1.5 g of each of A. sativum, C. frutescens and Z. officinale and 0.12 g of Permethrin were applied to 20 g of maize grains infested with S. zeamais under controlled conditions of 30 ± 2°C and 65 ± 5% R.H. In all the treatments, 100% mortality of adult S. zeamais reared on maize was obtained. The effect of the spices on adult mortality was significantly different (p

The repellency of solvent extracts of Calpurnia aurea leaves was evaluated on the maize weevils and the red flour beetles. Nine-cm Whatman number 1 filter paper that is partitioned into treatment, neutral and non-treatment portions was used for the experiment. Each solvent extract treatment was applied at 2.5, 5 and 10% rates. Insects were released in the neutral portion, while the untreated part served as a control. A choice bioassay experimental method that is laid down in a completely randomized design within three replications was used. 5 and 10% rates of the polar solvent extracts of Calpurnia aurea leaves induced significantly (p < 0.05) higher percentage weevils and beetles repellency (≥50.00%) at 2 days after treatment than non-polar and partial polar solvent extract treatments and the untreated check. 10% dosage of Calpurnia aurea leaves' polar solvent extract treatments caused 100% weevils and beetles repellency three days after treatment. Consequently, the polar solvent extracts of the tested plant were potent and could be used at 5 and10%rates for the maize weevils and the red flour beetles' management under farmers' maize storage conditions. Nevertheless, their impact on cost-effectiveness, natural enemies and human beings needs additional study. [ABSTRACT FROM AUTHOR]

Sitophilus zeamais is a primary pest of maize. Our aim was to perform a qualitative review and meta-analyses with 56 scientific articles published from 1 January 2000 to 1 October 2022 dealing with direct (topical application) and indirect (impregnation of essential oils, EOs, onto filter paper or maize grains) contact toxicity of EOs against S. zeamais. Three independent meta-analyses of single means of LD50 (direct contact) and LC50 (indirect contact) were conducted using a random effect model. Essential oils more frequently evaluated were those belonging to Asteraceae, Apiaceae, Lamiaceae, Myrtaceae, Piperaceae, and Rutaceae. The LC50 global mean values were 33.19 µg/insect (CI95 29.81–36.95) for topical application; 0.40 µL/cm2 (CI95 0.25–0.65) for filter paper indirect contact; and 0.50 µL/g maize (CI95 0.27–0.90) for maize grains indirect contact. The species Carum carvi, Salvia umbratica, Ilicium difengpi, Periploca sepium, Cephalotaxus sinensis, Murraya exotica, Rhododendron anthopogonoides, Ruta graveolens, Eucalyptus viminalis, Ocotea odorifera, Eucalyptus globulus, Eucalyptus dunnii, Anethum graveolens, Ilicium verum, Cryptocarya alba, Azadirachta indica, Chenopodium ambrosioides, Cupressus semperivens, Schinus molle, Piper hispidinervum, Mentha longifolia, and Croton pulegiodorus showed LC50 or LD50 values lower than the global means, indicating good insecticidal properties. Our results showed that EOs have great potential to be used as bioinsecticides against S. zeamais. [ABSTRACT FROM AUTHOR]

In Nigeria, maize serves as a staple food and a good source of carbohydrates, protein, vitamin B and minerals, hence, the need to protect it against Sitophilus zeamais. This study was conducted to determine the phytochemical properties and insecticidal potentials of Allium sativum bulb and bulb coat powders against Sitophilus zeamais. Allium sativum bulb and bulb coat were collected, dried, and pulverized into fine powder. A 0, 2.0, 3.0, 4.0, and 5.0g of the plant powder were used. Each treatment had 16 newly emerged maize weevils. The weevils were mixed with 250g un-infested maize grains in 500ml bottles and kept at room temperature. Mortality was observed for 7 days at 24 hours intervals post treatment. The experiment was laid out in a Completely Randomized Design and treatments were replicated three times. Data obtained were analyzed using a one-way ANOVA and means were separated using Duncan multiple Range test. The results revealed that both parts showed significant percentage mortality (P ≤ 0.05). The results showed that as the dosage of the bulb powder increased from 2 - 5g, percentage mortality increased from 16-32.8%. For bulb coat powder, percentage mortality increased from 16.5-32.1%. The control showed mortality of 3.0 and 2.8% for the bulb and bulb coat powders, which were significantly different (P < 0.05) from the mortality in treated maize. The most effective dosage for both powders is 5g. Based on the results obtained, Garlic bulb and garlic bulb coat could be used in the management of Sitophilus zeamais infestation.

Background: Sitophilus zeamais is a major pest of stored grains in Ghana and its control can be achieved through an Integrated Pest Management approach, which includes the judicious use of effective and selective insecticides. However, persistent use of synthetic protectants can cause insecticide resistance, militating against control. It is therefore important to monitor the effectiveness of these products to justify their continuous use and to detect the emergence of resistance. This study evaluated the efficacy of two commonly used commercial insecticide products namely Agricombi® (30% fenitrothion + 10% fenvalerate) and Betallic Super® (80 g pirimiphos-methyl + 15 g permethrin) on adult S. zeamais populations from three districts in the Central region of Ghana. Results: The median knockdown times (KT50s) of the products at their recommended label concentrations (RLCs) were 15.13–53.42 min for Agricombi® and 17.17–63.70 min for Betallic Super® while mortalities after 24 h of insecticide exposure were 52.00–80.00% and 21.33–58.67%, respectively. Concentration-response effect of the composite insecticide products showed median lethal concentrations (LC50s) of 8149–12827 mg/L for Agricombi® and 2638–4411 mg/L for Betallic Super®. Comparisons of the RLCs of the products and their respective LC50s and LC95s indicate decreased susceptibility in the weevil populations. Conclusions: The insecticides were ineffective against the S. zeamais populations at their recommended label concentrations. The decreased susceptibilities pose challenges for effective management of the pest and hence the need for alternative effective management methods or products with different active ingredients in these communities.

Inappropriate use of synthetic insecticides in pest management programs contribute in ozone depletion, neurotoxicity, carcinogenicity, teratogenicity, mutagenesis and resistance. These negative outcomes have diverted attention towards the use of plant products in insect’s population management. In this study, dill (Anethum graveolens) and star anise (Ilicium verum) essential oils were isolated by hydrodistillation method using clevenger apparatus, and evaluated for repellent, toxic and oviposition inhibitory potential against maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) by fumigation and contact methods. In toxicity assay by fumigation method, median lethal concentrations (LC50) recorded were 0.316 and 0.243 μlcm-3 air; 0.362 and 0.284 μlcm-3; and 0.497 and 0.418 μlcm-3 of A. graveolens and I. verum oils and pure limonene after 24 and 48h exposure to S. zeamais adults, respectively. In contact toxicity assay, LC50 were 0.219 and 0.159 μlcm-2 area; 0.269 and 0.226 μlcm-2; and 0.567 and 0.386 μlcm-2 of A. graveolens and I. verum oils and pure limonene after 24 and 48 h exposure to S. zeamais adults, respectively. Both A. graveolens and I. verum oils and limonene reduced progeny production and acetylcholinesterase activity in S. zeamais adults when fumigated with sub-lethal concentrations. The outcomes of this study will help in preparation of essential oil based formulations for stored grain insect pest management.

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.

Food security is contingent upon increasing crop yields but also upon reducing crop losses to post-harvest pests and diseases. Weevils are particularly important agents of post-harvest losses in grain crops. A long-term evaluation of a biocontrol agent, Beauveria bassiana Strain MS-8, at a single dose of 2 × 109 conidia kg−1 of grain was formulated in kaolin as a carrier at levels of 1, 2, 3, and 4 g kg−1 of grain and screened against the maize weevil, Sitophilus zeamais. After six months, the application of B. bassiana Strain MS-8 at all levels of kaolin significantly reduced the maize weevil populations compared to the untreated control (UTC). The best control of maize weevil was observed in the first 4 months after application. Strain MS-8 applied in a kaolin level of 1 g kg−1 performed the best, resulting in the lowest number of live weevils (36 insects/500 g of maize grain), the lowest level of grain damage (14.0%), and the least weight loss (7.0%). In the UTC the number of live insects was 340 insects/500 g of maize grain, the level of grain damage was 68.0%, and weight loss was 51.0%.

Synthetic pesticides are used indiscriminately in insect pest management, which damages the ozone layer and causes resistance in target organisms as well as neurotoxicity, carcinogenicity, teratogenicity and mutagenesis in non-target organisms. Due to these negative consequences, research is now focused on using plant-based techniques to control insect pests. The maize weevil, Sitophilus zeamais (Coleoptera: Curculionidae), was tested in the laboratory to determine the insecticidal effects of two pure essential oil constituents, namely ɑ-pinene and ß-caryophyllene. These two terpenes were tested against S. zeamais for their toxic, ovipositional, developmental, and feeding inhibitory effects. When S. zeamais adults were fumigated for 24 and 48hrs, the median lethal concentrations (LC50) of ɑ-pinene and ß-caryophyllene were 0.412 and 0.305 µlcm-³ and 0.486 and 0.315 µlcm-³ air respectively. When S. zeamais adults were exposed for 24 and 48hrs in a contact toxicity assay, the LC50 values for a-pinene and ß-caryophyllene were 0.388 and 0.256 µlcm-² and 0.308 and 0.216 µlcm-² area respectively. Adults exposed to sub-lethal concentrations of both terpenes experienced decreased acetylcholine esterase (AChE) enzyme activity. In S. zeamais, a-pinene and ß-caryophyllene decreased oviposition, progeny output and eating. According to this study, a-pinene and ß-caryophyllene can be used to make environmentally acceptable formulations and as a substitute for synthetic insecticides. [ABSTRACT FROM AUTHOR]

Maize is one of the major staple foods in Sub-Saharan Africa and there is serious loss in maize storage due to insect damage. This study compared the bioactivity of Bamboo Leaf Ash (BLA) and Bularafa Diatomaceous Earth (BDE) against Maize Weevil (Sitophilus zeamais Motschulsky) under laboratory conditions. Insecto®, a commercialized DE was also tested as standard check. Adults of the insects were exposed on maize admixed with the BLA at dose rate of 5,000, 10,000 and 20,000ppm; BDE and insecto® at a dose rate of 1,000ppm, at 28.20C and 82.2% relative humidity. Mortality increased with increasing exposure duration and all treatments showed mortality of more than 80% after 14days post-treatment compared to negative control with 0%. The treatments suppressed F1 progeny. Treated grains have weight loss less than 4%, kennel damage less than 14% and grain germination showed no significant change. The decreasing efficacy of the dusts against this insect is Insecto®> BLA > BDE. BLA and BDE have potential for the management of insect pests of stored grain in Nigeria. [ABSTRACT FROM AUTHOR]

Experiments were carried out to assess the protectant ability of cow dung ash (CDA) to maize grains against Sitophilus zeamais Motsch. under laboratory conditions of 28-32oC and 60-75% relative humidity (R.H.). The CDA at different doses of 0.625, 1.25, 2.50, 5.00, 10.00% (w/w) were used and permethrin powder at 0.625% used as positive control, negative control were also set up in different Petri dishes to which no permethrin or ashes were added. Five pairs of weevils were introduced into each of the Petri dishes and covered with muslin cloth. The experiment was arranged in a completely randomized design (CRD) and replicated three times. Effect of the treatments on adult mortality was determined. Adult emergence and weight losses in seeds treated with CDA at different doses were also assessed. Findings of the study revealed that the adult mortality of S. zeamais among different CDA doses differed significantly (p < 0.05) and ranged from 13.33 to 100.00% at 96 hours after treatment (HAT). Results of the study also showed that LD50 of CDA against S. zeamais at 24 hours after treatment (HAT) was 4.57 % (w/w). There were no F1 adult emergences of S. zeamais in all the treatments. Weight losses were found to differ significantly (P

Maize is one of the major staple foods in Sub-Saharan Africa and there is serious loss in maize storage due to insect damage. This study compared the bioactivity of Bamboo Leaf Ash (BLA) and Bularafa Diatomaceous Earth (BDE) against Maize Weevil (Sitophilus zeamais Motschulsky) under laboratory conditions. Insecto®, a commercialized DE was also tested as standard check. Adults of the insects were exposed on maize admixed with the BLA at dose rate of 5,000, 10,000 and 20,000ppm; BDE and insecto® at a dose rate of 1,000ppm, at 28.20C and 82.2% relative humidity. Mortality increased with increasing exposure duration and all treatments showed mortality of more than 80% after 14days post-treatment compared to negative control with 0%.The treatments suppressed F1 progeny. Treated grains have weight loss less than 4%, kennel damage less than 14% and grain germination showed no significant change. The decreasing efficacy of the dusts against this insect is Insecto®> BLA > BDE. BLA and BDE have potential for the management of insect pests of stored grain in Nigeria.

Simple Summary: Sitophilus zeamais is a worldwide pest that destroys many grain products, causing a loss of cereal quality and quantity resulting from its metabolites and behavior. Glutathione S-transferases (GSTs), as a group of odorant-degrading enzymes (ODEs), play an important role in degrading xenobiotic odorant molecules in insect olfactory sensing systems. However, there have been few reports about the function of the GST genes of S. zeamais in the odorant-degrading process. In this study, we characterized 13 full-length genes encoding GST sequences from S. zeamais and analyzed the expression pattern in different tissues of SzeaGSTd1. In addition, we investigated the ability of recombinant SzeaGSTd1 to degrade the volatile molecules of the host, and the data indicated that the content of capryl alcohol significantly decreased in the system. In summary, we believe SzeaGSTd1 plays a key role in the olfactory sensing system of S. zeamais. Odorant-degrading enzymes (ODEs) play an important role in rapidly degrading and inactivating odorant molecules that have completed information transmission, as well as in maintaining the stability and sensitivity of insect olfactory sensing systems. Glutathione S-transferases (GSTs), as a group of ODEs, supposedly bear the ability to catalyze the conjugation of glutathione (GSH) and xenobiotic odorant molecules in the degrading process. However, there are few reports regarding the role of the GST genes of Sitophilus zeamais in the degrading process. Thus, we characterized 13 full-length genes encoding GST sequences from S. zeamais, of which only SzeaGSTd1 contained a high abundance in the antennae. Ligand-binding assays implied that SzeaGSTd1 was able to catalyze the conjugation of GSH with 2, 4-dinitrochlorobenzene (CDNB). We investigated whether recombinant SzeaGSTd1 bears the ability to degrade the volatile molecules of the host; among the host volatiles, and found capryl alcohol to be a suitable substrate for SzeaGSTd1. These results strongly suggest that SzeaGSTd1 probably plays a role in auxiliary host location by degrading the host volatiles of capryl alcohol and exhibits a potential biological function in the olfactory sensing system of S. zeamais. Knowledge of the potential functions of SzeaGSTd1 will provide new ideas for biological control strategies for S. zeamais. [ABSTRACT FROM AUTHOR]

The relationship between T. castaneum and S. zeamais was studied through reciprocal selectivity experiment, single rearing and mixture rearing at 30 ℃, 75% RH. The results showed that the mutual selection behavior between the two species was not obvious in the same ecological environment. The number of T. castaneum adults in the population decreased first, then increased slowly with increasing treatment time,the maximum number of adults in the population reaching 11.5 times of the initial number after 56 d rearing alone in wheat. while the number of S. zeamais adults in the population increased obviously with increasing treatment time, and reaching 53.9 times of the initial number after 56 d rearing alone in wheat. Compared with rearing alone, the number of adults in the population of both T. castaneum and S. zeamais significantly increased under mixture rearing in wheat, the maximum adults in the population reaching 20.3 and 93.4 times of the initial number respectively after 56 d. Therefore, both T. castaneum and S. zeamais are important pest insects during wheat storage, and the S. zeamais infestation can promote the growth of T. castaneum population.

Plantas com efeito inseticida apresentam-se entre as alternativas como ferramenta de controle dos insetos-praga de grãos armazenados. No presente estudo, objetivou-se caracterizar a eficiência dos pós de origem vegetal sobre Sitophilus zeamais em grãos armazenados. Foram avaliados 14 pós vegetais (Arnica montana Baccharis trimera Less., Coriandrum sativum L., Coffea arabica, Cymbopogon martini, Helianthus annuus, Lippia gracillis, Mentha pulegium L., Moringa oleífera, Nicotiana tabacum, Piper aduncum, Piper hispidinervum, Sesamum indicum e Vitis labrusca) obtido de material vegetal triturado, e comparado com um tratamento controle. O experimento foi realizado em delineamento inteiramente casualizado, com seis repetições cada tratamento. Nos testes, 0,5 g dos pós inertes foram misturados aos grãos (50 g) de milho híbrido AS 1551 dentro de frascos plásticos, sendo infestados com 10 S. zeamais adultos emergidos. Após 20 dias da infestação avaliou-se a oviposição e iniciou-se a contagem de adultos emergidos. Ao fim do período de infestação, foi avaliado o peso seco dos insetos, o peso de grãos consumidos e o período de desenvolvimento (ovo-adulto). A maioria dos pós vegetais apresentou atuação efetiva sobre os insetos emergidos. Constatou-se nos pós testados redução na oviposição, exceto Vitis labrusca e Sesamum indicum cujo número de ovos foi superior ao controle, também apresentaram menor efeito sobre o desenvolvimento das larvas do caruncho. O baixo peso de adultos provenientes de grãos de milho tratados com pó de Nicotiana tabacum sugere a ocorrência de deterrência na alimentação das larvas de S. zeamais.

Sitophilus zeamais is a primary pest of maize. Our aim was to perform a qualitative review and meta-analyses with 56 scientific articles published from 1 January 2000 to 1 October 2022 dealing with direct (topical application) and indirect (impregnation of essential oils, EOs, onto filter paper or maize grains) contact toxicity of EOs against S. zeamais. Three independent meta-analyses of single means of LD50 (direct contact) and LC50 (indirect contact) were conducted using a random effect model. Essential oils more frequently evaluated were those belonging to Asteraceae, Apiaceae, Lamiaceae, Myrtaceae, Piperaceae, and Rutaceae. The LC50 global mean values were 33.19 µg/insect (CI95 29.81–36.95) for topical application; 0.40 µL/cm2 (CI95 0.25–0.65) for filter paper indirect contact; and 0.50 µL/g maize (CI95 0.27–0.90) for maize grains indirect contact. The species Carum carvi, Salvia umbratica, Ilicium difengpi, Periploca sepium, Cephalotaxus sinensis, Murraya exotica, Rhododendron anthopogonoides, Ruta graveolens, Eucalyptus viminalis, Ocotea odorifera, Eucalyptus globulus, Eucalyptus dunnii, Anethum graveolens, Ilicium verum, Cryptocarya alba, Azadirachta indica, Chenopodium ambrosioides, Cupressus semperivens, Schinus molle, Piper hispidinervum, Mentha longifolia, and Croton pulegiodorus showed LC50 or LD50 values lower than the global means, indicating good insecticidal properties. Our results showed that EOs have great potential to be used as bioinsecticides against S. zeamais.

Purpose: The control of stored-grain insect pests is predominantly done through the use of synthetic insecticides. However, the extensive and constant (mis)use of these chemicals has brought complications that include faster evolution of resistant forms of pests, hence a global call for alternative control measures to reduce chemical applications. The aim of this research was to evaluate the repellent and toxic effects of E. citriodora leaf powder on adult P. truncatus and Sitophilus zeamais. Research Method: A completely randomized design was adopted in all the experiments. A choice test arena was set up to evaluate repellent effects of E. citriodora leaf powder on P. truncatus and S. zeamais. The toxic effect of E. citriodora was also evaluated, with untreated grain and conventional insecticides used as negative and positive controls, respectively. Findings: Results showed that E. citriodora leaf powder had repellent properties of up to 68.9% against both P. truncatus and S. zeamais populations. Nonetheless, low adult P. truncatus mortalities were recorded when the protective effects of the E. citriodora leaf powder (at the rate of 10% w/w) were tested against the beetle. Additionally, the efficacy of the synthetic insecticides was relatively higher when applied singly than when in combination with E. citriodora leaf powder. Research limitations: Time was the major limiting factor to consider other parts of E. citriodora plant (e.g. roots) on their usefulness in stored-product insect pest management. Originality/Value: Small plantations of E. citriodora may be established to offer a temporary grain protection against primary insect pests.

Alternative methods of control against different parasites affecting livestock and agriculture are currently being sought. The essential oil of Peumus boldus Molina has anthelmintic and insecticidal activity against the nematode Haemonchus contortus and stored cereal insect pests. The present study aimed to assess the in vitro activity of P. boldus essential oil against H. contortus (L3) unsheathed and Sitophilus zeamais, Tribolium castaneum, and Plodia interpunctella. The essential oil was obtained from leaves of P. boldus and its principal compounds identified by phytochemical analysis. Essential oil was tested at concentrations of 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2.0 mg mL-1 on unsheathed L3 H. contortus larvae and in concentrations of 0, 35, 70, 100, 125, 150, 175 and 200 μL L-1 air on adult insects. The main constituents detected in the essential oil were 1,8-cineole, terpineol, terpinene-4-ol, γ-terpinene, p-cimene, methyl eugenol, safrole, (E)-germacrene D, β-tujene, and ascaridol. The nematode H. contortus and insects were exposed to the essential oil for 72 h. In a bioassay with H. contortus larvae, treatment with 2.0 mg mL-1 showed the highest toxicity with 99.2% mortality. Regarding insecticidal activity, S. zeamais was the most susceptible species with a mortality of 90% at 200 μL L-1 air. The present study suggests that the essential oil of P. boldus has potential anthelmintic and insecticidal activity. [ABSTRACT FROM AUTHOR]

The maize weevil (Sitophilus zeamais) is one of the main insect responsible of significant losses in stored products, and to keep nutritional value of them to find effective and safe solutions are very important. The Hypericum genus might be a potential source of new bio-insecticides due to the chemical composition of essential oils. In this study, components of essential oils of three Hypericum species were investigated for first time by Gas Chromatography-Mass Spectrometry (GC-MS) and, fumigant and contact toxicities as well as the repellent activity of essential oils of them were evaluated against S. zeamais adults. While the main components in H. mexicanum oil were determined as n-nonane (53.08%) and α-pinene (25.28%), the major constituents were determined as α-pinene (45.52%) and β-caryophyllene (13.59%) in the essential oil of H. myricariifolium. Chemical composition of essential oil of H. juniperinum were found to be n-nonane (12.0%), α-pinene (8.25%), geranyl acetate (7.93%), and β-caryophyllene (13.60%). The results revealed that H. mexicanum and H. myricariifolium oils have fumigant toxicity (LC50 < 500 µL/L air) and a potential action as repellents (RP > 70% at 6.2--22.7 μL/L air) for the control of the pest. [ABSTRACT FROM AUTHOR]

Sitophilus zeamais and Prostephanus truncatus can cause weight loss of about 20 to 90% of untreated stored maize seeds. This study assesses four plants (Lantana camara, Moringa oleifera, Citrus sinensis and Hyptis suaveolens) extracts as seed maize protectants against the two insects in Ghana. The study was laid out in a CRD with three replications. Dried powders (5 and 10% w/w) and aqueous extracts (0.05 and 0.1 g/mL) of the botanicals were evaluated for their insecticidal activity with untreated control and Actellic included as checks. Oviposition and survivorship of insects decreased in grains treated with plant extracts. The phytochemical analysis revealed that compounds such as alkaloids, saponins, tannins and phenolic, steroids, flavonoids, anthraquinones, phlobatannins, cardiac glycosides and terpenoids were recorded in all four plant extracts. These compounds may have caused lower progeny emergence, inhibitory effect, repellent action and antifeedant effect to S. zeamais and P. truncatus in grains treated with the botanicals. Maize seeds treated with botanicals after 10 weeks in cribs recorded a reduction in the percentage of seeds damaged and weight loss caused by the two insects compared to the untreated seeds. The study proposes that the botanicals tested, especially H. suaveolens have the potential to enhance quality seed production thereby boosting growth in the seed industry. The botanicals are recommended for use by seed producers and farmers to control P. truncatus and S. zeamais in stored maize seeds.

Considering the edibility of insects’ species associated with storage ecosystem, chemical control methods can be easily replaced by environmental and economically sustainable alternatives. Use of biogenerated atmospheres is an inexpensive method that tolerates insect presence. In Portugal, during one year, hermetic bags were used to store paddy under 65-75-85% relative humidity (RH) and 14-17-24ºC temperatures. Brown rice infested with Sitophilus zeamais adults was placed inside the hermetic bags. Biogenerated atmosphere was naturally produced inside the hermetic bag, at 85% RH, with low O2 and high CO2 contents, showing that S. zeamais can survive but has no progeny at 14º-17ºC, or attained 100% mortality before producing progeny at 24ºC. The most abundant fungi isolated were Alternaria alternata and Epicoccum nigrum. The results showed the importance of the RH on changes in atmospheric gas content of paddy, due to biological agents’ activity. Analysing the edibility of insects species associated with stored grain, preliminary studies were carried out to evaluate the nutritional value of immatures stages of Tribolium castaneum. Larvae of T. castaneum had a content of 21.4% protein, 9.1% lipids, 8.8% fiber, and a relevant content of eight essential amino acids and also manganese and copper. The edibility of insects must be consider given their high nutritional value, low emissions of Green House Gases (GHGs), low requirements for land, and by reducing and mitigating the need for chemical control.

The objective of this study was to investigate the characteristics of adult Sitophilus zeamais and Tribolium castaneum, and the 21.1% dry base (d.b.) MC of rough rice by ATR-FTIR spectra, and determine the theoretical optimum infrared (IR) heating temperature of the tested samples. In laboratory experiments, a ceramic IR drying device was used to heat infested rough rice to research the mortality of Sitophilus zeamais and Tribolium castaneum, the drying characteristics of rough rice, and milling quality. The theoretical calculation optimum temperature of IR heating was 300 ˚C according to the results of FTIR spectra. In addition, the effects of the different IR radiation intensities and heated rough rice temperatures on mortality of insects, moisture removal, and milling quality were determined in this text. A high insect mortality, heating rate and corresponding high moisture removal were achieved by using IR heating. After heating, tempering process significantly increased insect mortality when the heated tempered rice temperature was less than 55 ˚C, and improve moisture removal and milling quality of rough rice during nature air cooling. When the rice heated under the IR radiation intensity of 2780 W/m2 for 110 s, the rice temperature reached 60.2˚ ± 0.5˚C, 100% mortality of S. zeamais and T. castaneum, and 3.97 percentage points of moisture removal during the heating period after tempering and natural cooling. In addition, the high rice milling quality can be achieved after tempering treatment. Therefore, it can be concluded that the optimum conditions of simultaneous disinfestation and drying were 60 ˚C rice temperature under the IR radiation intensity of 2780 W/m2, followed by tempering and natural cooling.

ECO₂FUME® fumigation of maize bag stacks under gas proof sheets was conducted to establish the optimal dosages (application rate) and exposure times (fumigation period) against mixed-age cultures of Sitophilus zeamais and Tribolium castaneum. The Complete Randomized Design (CRD) experimental design was employed, with 3 replications and 4 treatments. The experiments were divided into three groups: 1) treatment with a 25 g/m3 ECO₂FUME® application rate (350 ppm phosphine) for 3, 4, and 5 days and a control treatment; 2) treatment with an ECO₂FUME® application rate of 50 g/m3 (700 ppm phosphine) for 2, 3, and 4 days and a control treatment; and 3) treatment with a 70 g/m3 ECO₂FUME® application rate (1,000 ppm phosphine) for 1, 2, and 3 days and a control treatment. The three target phosphine concentrations of 350 ppm, 700 ppm and 1,000 ppm were maintained during the whole fumigation period. Results of the studies showed that no insect was alive at all dosages and exposure times. The studies also indicated that fumigation with ECO₂FUME® could reduce the fumigation period by increasing the phosphine concentration. The effective fumigation protocols on maize against mixed-age cultures of S. zeamais and T. castaneum were ECO₂FUME® application rates of 25 g/m3 for 3 days, 50 g/m3 for 2 days and 70 g/m3 for 1 day. The target phosphine concentration must be maintained throughout the fumigation period to achieve 100% mortality of all stages of insects.

Filter cake and Triplex are powdered by-products of aluminum sulfate and soap factories, respectively. There is limited data about the use of these powders as grain protectants. This study was aimed at determining contact toxicity of both powders against Sitophilus zeamais, a common pest of stored grains. Lethal concentration of both powders to S. zeamais was determined by exposing 10 adults for 12 h in 9 cm diameter concrete arenas inside Petri dishes dusted with filter cake (0 - 8 g/m²) or Triplex (0 - 9 g/m²). Lethal time was determined by exposing adults to 3 g/m² filter cake and 9 g/m² Triplex for 1 to 24 h. Each treatment was replicated 3 times. At the intended exposure time, adults were transferred to 150-ml round plastic containers with 30 g of wheat and held at 28 degree Celsius and 65% r.h. for 14 d to determine mortality. Adult progeny production was determined after 42 d. A 50% mortality of adults was obtained at 0.61 g/m² of filter cake and 1.61 g/m2 of Triplex concentrations with a 12 h exposure. The corresponding effective concentrations for 50% reduction of progeny production were 0.18 g/m² of filter cake and 2.66 g/m2 of Triplex. Lethal times for 50% mortality of adults after exposure to 3 g/m² of filter cake and 9 g/m2 of Triplex were 4.42 and 4.29 h, respectively. The corresponding effective times for 50% reduction of progeny production after exposure to 3 g/m² of filter cake and 9 g/m² of Triplex were 1.74 and 2.34 h respectively. The overall result indicated that filter cake was highly toxic to S. zeamais than Triplex. Therefore, filter cake is a potential powder to be included in the integrated pest management practice in small holder farmers’ storage structures after tested under real field conditions.

Plants are a source of substances for protection of stored products. The Cuban flora has not yet been fully studied as a source of pesticides for postharvest protection, partly due to its great diversity. The toxicity of four Cuban plant derivatives against Lasioderma serricorne (F.) and Sitophilus zeamais Motschulsky was investigated. The anti-insect activity of the powders and the essential oil from plants belonging to Asteraceae, Fabaceae and Piperaceae was tested. Mortality and emergence of adult insects and the repellent effect of products were evaluated. Two products derived from Piper aduncum subsp. ossanum, caused high mortality (81,6 and 100%), reduced emergence (27,9 and 0,4%) and exhibited strong repellent activity on L. serricorne. Against S. zeamais, treatments with the highest mortality values were stems of Lonchocarpus punctatus (72,4%), seeds and stems of Canavalia ensiformis (64,9 and 69,9%), and leaves of Tithonia diversifolia (67,2%). The progeny production of S. zeamais was inhibited by powders of L. punctatus stems (31,8%), C. ensiformis seeds (40,5%), leaves (43,7%) and stems (30,6%), and T. diversifolia leaves (38,7%). The stems of C. ensiformis, leaves of T. diversifolia and L. punctatus had the highest repellent effect. These products have potential for small-scale treatments of grains for protection against both insects, and P. aduncum subsp. ossanum-based products to control L. serricorne infestation in tobacco. Identification of local candidates to develop effective and safe pesticides offers new alternatives to the Cuban agriculture in the control of storage pests.

Combinations of botanicals could enhance biological activity against insects. This in turn, will reduce amount of botanical used in storage protection. In this issue, the bioassay was carried out on Sitophilus zeamais to assess the effectiveness of binary combinations of Hymenocardia acida wood ash and Plectranthus glandulosus leaf powder regarding adult toxicity, progeny inhibition, and reduction of damage and germination ability. Plectranthus glandulosus leaf powder, H. acida wood ash and their binary combinations significantly induced mortality of S. zeamais adult (P? 0.0001). The higher mortality rate was achieved by the highest content (40 g/kg) of H. acida wood ash (94.66%) and 25PG75HA (94.59%) within 14 days of exposure. The combinations of P. glandulosus leaf powder with H. acida at different proportions produced different interactions. The combination made up by 75% of P. glandulosus leaf powder with 25% of H. acida wood ash produced synergistic effect whereas that made up by 50% of each of two powders had antagonistic effect in weevil mortality. The three combinations of H. acida and P. glandulosus significantly reduced the progeny production. In term of inhibition of F1, the combination 25PG75HA revealed more effective than the two other. The grain damage and population increase were significantly reduced. In general, the non-infested maize grain had a good germination rate than the infested ones. The treatments did not have negative effect on seed germination. From These results, the two powders and their binary combinations could be used to reduce grain infestation by insect while taking in account the proportions of insecticidal powders implied in the combination.

The aim of this study was to determine the insecticidal efficacy of mixture of NeemAzal a commercial neem product and Plectranthus glandulosus leaf powder against Callosubruchus maculatus and Sitophilus zeamais. Mixed at various proportions (100 + 0, 75 + 25, 50 + 50, 25 + 75 and 0 +100%, these powders were tested on adult mortality, inhibition of offspring production and their persistence on C. maculatus and S. zeamais. All the mixed NeemAzal and P. glandulosus caused significant mortality to adult C. maculatus and S. zeamais. No significant difference was observed among the mixed powders that were subjected to the three mixture proportions regarding the mortality they caused to the weevils. The mixed 75% NeemAzal + 25% P .glandulosus of powder led to a higher mortality (100%) of both insect species, three (5 g/kg) days post exposure. The three days LC50 values decreased with ascending proportion of NeemAzal in the mixture from 3.21 g/kg (25% NeemAzal + 75% P. glandulosus) to 0.24 g/kg (75% NeemAzal + 25% P. glandulosus) in S. zeamais. In C. maculatus, the opposing effect was observed. The number of F1 progeny produced reduced significantly (P ≤ 0.01) in both insect species with the mixture proportion of botanicals. The mixtures reduced better the adult progeny production than the botanicals applied alone. The 75% P. glandulosus + 25% NeemAzal persisted well on grains up to 180 days for all dose levels. Powder from NeemAzal and P. glandulosus leaves stand as good candidates to protect maize and cowpea against the infestation of S. zeamais and C. maculatus respectively during storage. Mixing these products could not be advantageous since the binary mixture gave similar result as when they were applied alone.

Abstract Background Botanicals are generally assumed to be more biodegradable, leading to less environmental problems. Combination of botanicals could enhance biological activity against insect pests. Hence, the amount of botanical used for the control of stored grain pests may be minimised. In this study, the bioassay was carried out on Sitophilus zeamais to assess the effectiveness of binary combinations of Hymenocardia acida wood ash and Plectranthus glandulosus leaf powder. The quantities of mixed products were added to maize grains to constitute the contents of 5, 10, 20 and 40 g/kg. Then, the bioassays on toxicity within 1, 3, 7 and 14 days exposure, progeny production, population increase, grain damage and germination ability of protected grains were carried out. Results The major compounds (pinene, α-pinene, α-terpineol, thymol, β-myrcene and 3-carene) of P. glandulosus leaf powder were monoterpenes. The major non-monoterpenic constituent was an oxygenated sesquiterpene, β caryophyllene oxide. The chemical analysis of H. acida ash showed that calcium (5800 mg/kg) and phosphorus (2782 mg/kg) recorded higher content than the other minerals. Plectranthus glandulosus leaf powder, H. acida wood ash and their binary combinations significantly induced mortality of S. zeamais adult (P

Sitophilus zeamais and Prostephanus truncatus can cause weight loss of about 20 to 90% of untreated stored maize seeds. This study assesses four plants (Lantana camara, Moringa oleifera, Citrus sinensis and Hyptis suaveolens) extracts as seed maize protectants against the two insects in Ghana. The study was laid out in a CRD with three replications. Dried powders (5 and 10% w/w) and aqueous extracts (0.05 and 0.1 g/mL) of the botanicals were evaluated for their insecticidal activity with untreated control and Actellic included as checks. Oviposition and survivorship of insects decreased in grains treated with plant extracts. The phytochemical analysis revealed that compounds such as alkaloids, saponins, tannins and phenolic, steroids, flavonoids, anthraquinones, phlobatannins, cardiac glycosides and terpenoids were recorded in all four plant extracts. These compounds may have caused lower progeny emergence, inhibitory effect, repellent action and antifeedant effect to S. zeamais and P. truncatus in grains treated with the botanicals. Maize seeds treated with botanicals after 10 weeks in cribs recorded a reduction in the percentage of seeds damaged and weight loss caused by the two insects compared to the untreated seeds. The study proposes that the botanicals tested, especially H. suaveolens have the potential to enhance quality seed production thereby boosting growth in the seed industry. The botanicals are recommended for use by seed producers and farmers to control P. truncatus and S. zeamais in stored maize seeds. [ABSTRACT FROM AUTHOR]