Sitophilus Zeamais Research Articles

Baccharis essential oils from the Atlantic Forest as sources of natural pesticides

Substances derived from bioactive plants of the Atlantic Forest can potentially be used for agricultural pest control, with fewer environmental consequences than other measures. Baccharis species present several biological properties, including insecticidal action. The present study aimed to characterize and evaluate the insecticidal activity of the following essential oils (EOs) obtained from native species of the Atlantic Forest: Baccharis articulata (Lam.) Pers., Baccharis calvescens DC., and Baccharis milleflora (Less.) DC. (Asteraceae), the last two of which are endemic to Brazil. EOs were obtained by steam extraction in a vat for 3 h, and the constituents were identified by gas chromatography coupled to mass spectrometry (GC/MS). Insecticidal activity was evaluated against Anticarsia gemmatalis, Sitophilus oryzae, Sitophilus zeamais, and Lucilia cuprina. A total of 7, 16, and 27 compounds were identified in EO samples from B. articulata, B. calvescens, and B. milleflora, respectively. All EOs caused 100 % mortality to A. gemmatalis, and 76.67 %, 98.33 %, and 95 % mortality to L. cuprina using EOs of B. milleflora, B. calvescens, and B. articulata, respectively. Only B. articulata caused mortality greater than 80 % to S. zeamais (83.88 %) and S. oryzae (86.03 %) by fumigation. The present study provides information on the use of EOs from Baccharis species as natural alternative substances to chemical pesticides, contributing to more sustainable production in Brazilian agriculture.

Host Volatiles Potentially Drive Two Evolutionarily Related Weevils to Select Different 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.

Phytochemical screening and insecticidal activities of some medicinal plants against the maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae)

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) in the cumulative mean percentage mortality of the maize weevil. The seed extract of Maesa lanceolata and Croton macrostachyus and the leaf extract of Clausena anisata showed cumulative percent mortality ranged 95.32–98.02% in 28 days after treatment application. There was no significant difference (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 (Coleoptera: Curculionidae) and In Vitro Inhibition of the Acetylcholinesterase Enzyme of 11 Essential Oils from Six Plants of the Caribbean Region of Colombia.

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.

Plant-Based Insecticides for Control of Aedes aegypti, Sitophilus zeamais and Nasutitermes corniger: A Review and Bibliometric Analysis

Insect pests can transmit diseases or affect the economy and their uncontrolled growth is intensified by human activity, which has affected ecosystems and interfered with trophic chains. Aedes aegypti L. transmits dengue, chikungunya, zika and yellow fever, while Sitophilus zeamais Motsch is a stored grain pest, and Nasutitermes corniger Motsch attacks trees and urban buildings. This work provides a review of the state of art and current trends, as well as a bibliometric analysis on the insecticidal activity of plant-based products against Ae. aegypti, S. zeamais and N. corniger. The review of literature data showed that plant insecticides comprise secondary metabolites and proteins that can impair the viability of embryos, larvae, pupae, and adults, as well as fertility and oviposition or feeding behavior of insects. Also, they tend to be more biodegradable and less harmful to non-target organisms compared to synthetic insecticides. The bibliometric analysis revealed the concentration of publications in tropical regions worldwide, where there is a strong occurrence of diseases transmitted by Ae. aegypti. These reports were far more numerous than those on N. corniger and S. zeamais. Furthermore, the synthesis of metallic nanoparticles from plant products has strongly emerged as a current trend.

Effect of Moringa oleifera Leaf Powder and Seed Oil on Insect Pests of Stored Maize and Cowpea

The leaf powder of Moringa oleifera was applied as direct admixture at 5g, 10g and 15g while the seed oil was applied at 5ml and 10ml to 100g each of Maize and Cowpea grains respectively, while the control was without insecticide application to test for insect mortality., progeny development and damage caused on stored maize and cowpea (Sitophilus zeamais and Callosobruchus maculatus). The experiment was laid out in a Completely Randomized Design (CRD) and results obtained were subjected to analysis of variance (ANOVA) while means were separated using the Least Significant Difference (LSD). The result showed significantly (P&lt;0.05) progeny reduction of adult Sitophilus zeamais and Callosobruchus maculatus using Moringa oleifera leaf powder at different concentration 0, 5g (23.90, 28.62), 10g and 15g respectively. Control (0) recorded the highest number 68.51 in Callosobruchus maculatus, and 56.85 in Sitophilus zeamais. Mortality test result showed that moringa leaf powder significantly(P&lt;0.05) increased the mortality of adult S. zeamais and C. maculatus with increase in concentration after 96 hours of exposure while moringa seed oil offered 100% mortality after 24 hours of exposure. Germination of maize and cowpea was not affected after treatment with moringa leaf powder and seed oil. Contact toxicity result showed significant adult mortality of S. zeamais and C. maculatus on filter paper with 15% mortality in C. maculatus and 10% in S. zeamais. Damage was significantly reduced in treated grains compared with the untreated control. Moringa seed oil was more toxic to S. zeamais and C. maculatus compared to moringa leaf powder and the untreated control. The protective effect of moringa seed oil against S. zeamais and C. maculatus comes principally through oviposition suppression and reduced or complete inhibition of adult emergence, consequently reducing or eradicating infestation risk, damage and loss of maize and cowpea grains in storage. While the use of plant essential oils against storage insect pest is being advocated, the availability, affordability and the tendency of tainting protected grains should be considered.

Citrus limon Wastes from Part of the Eastern Cape Province in South Africa: Medicinal, Sustainable Agricultural, and Bio-Resource Potential.

The fruits of Citrus limon are often purchased for their vitamin C-rich juice, while the fruit peel and the tree leaves are discarded as wastes. This study obtained the chemical profiles of the essential oils (EOs) of C. limon wastes (the peel and leaves), evaluated their medicinal value as antioxidants, their potential for sustainable use in agriculture as an insecticide for post-harvest preservation of grains, and their potential as a bioresource in livestock feed formulations. The EOs were isolated from C. limon leaves and peel using a hydro-distillation method on a Clevenger apparatus. The oil constituents were identified using the gas chromatography-mass spectrometry (GC-MS) hyphenated technique. The oils were evaluated for their in vitro antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power methods. An insecticidal study was conducted using contact toxicity, fumigation, and repellence bioassay methods against Sitophilus zeamais (maize weevils). Finally, the predicted income from using lemon peel as an alternative or substitute ingredient for maize in livestock feed formulations was obtained through a conventional simulation method. Chemically, limonene was found to be present in all the EOs analyzed (12-52%), while α-pinene was only found in the fresh leaf and peel oils (13.3% and 10.6%). Caryophyllene oxide was identified as the major component of the dried leaf oil (17.7%). At 20 µg m, the dry peel oil exhibited the highest inhibitory activity (52.41 ± 0.26%) against the DPPH radical, which was comparable to L-ascorbic acid (a standard antioxidant) at 54.25 ± 3.55%. The insecticidal study revealed that the dry peel oil is a better insect repellent (73.33 ± 6.95% at 10 µL) and fumigant (LC50 = 0.17 µL g-1 after 48 h) natural agent compared to the peel oil. Conversely, the dry peel oil showed a better contact activity (LC50 = 1.69 µL g-1) against the maize weevils compared to the dry leaf oil. The simulation study showed the cost of using dry lemon peel as an alternative to maize in livestock feed formulation to be ZAR 2.8 billion, compared against the higher cost of feed formulation with maize, which currently stands at ZAR 24.9 billion. This study has shown that C. limon wastes (the peel and leaves) contain EOs with unique chemical profiles, valuable medicinal properties as free radical scavengers, and considerable insecticidal properties for agricultural use in post-harvest grain preservation, presenting a cost-effective and promising bioresource for livestock feed production.

Mechanical stirring of bulk-stored maize in steel bins to suppress maize weevils and other beetle populations

This study investigates the effectiveness of periodic stirring as a non-chemical approach to suppress maize weevils, Sitophilus zeamais, and other beetle populations in large-scale grain storage bins. The research was conducted in a farm steel bin with a diameter of 9.8 m holding 127 Mg of maize, and a control bin of diameter 7.3 m holding 102 Mg of maize. Both bins were loaded with maize at 13% moisture and infested at a commercial tolerance rate of 2 weevils/kg of maize. Probe traps monitored beetle populations except for S. zeamais before stirring was initiated. Maize samples were collected at depths of 0, 0.9, 1.8 and 2.7 m with a vacuum-probe sampler prior to stirring and at 10, 20, 30 and 40 days of continuous stirring machine operation. Stirring achieved 100% control of live S. zeamais while the control bin experienced an increase in its S. zeamais population after 40 days. The stirring process also led to a significant reduction in dominant beetle populations such as hairy fungus beetles, Typhaea stercorea, and foreign grain beetles, Ahasuerus advena. Although the quality of maize in both bins changed at different depths and storage times, the treatment bin had higher bulk density (732.7 ± 3.98 kg/m3 to 768.9 ± 2.41 kg/m3), lower insect damage (0.02 ± 0.02% to 0.9 ± 0.28%), and higher allowable storage time (>249 days). Moisture content and molded kernels increased in the control bin, reaching 26.4 ± 1.29% and 3.2 ± 0.53%, respectively. The average percentage of broken corn and foreign material (BCFM) in the sweepings on the floor of the emptied treatment bin was 6.5 times higher than that in the control bin. Calculated packing factor values below 1.5 from the sweepings indicated that BCFM concentrations did not affect airflow. Stirring maize provides an alternative to the use of chemicals to control stored maize insect pests at a production scale.

Analysis of potential volatile organic compounds in Sitophilus zeamais (Coleoptera: Curculionidae)-infestedwheat based on lipid oxidation-a reference to early and rapid detection method.

The maize weevil, Sitophilus zeamais Motschulsky, is a hidden pest that presents serious risk to grain quality during postharvest storage. Lipid-derived volatile detection is considered a key reference for early prediction of S. zeamais infestation. However, the exact compositions of fatty acids and volatile organic compounds (VOCs) in S. zeamais-infested wheat are yet to be determined. In this study, we aimed to explore the effect of S. zeamais infestation on lipid metabolism in wheat infested with S. zeamais eggs (4 days), larvae (20 days), pupae (35 days), and adults (45 days). Compared to those in the control group, the activities of lipid oxidation enzymes, such as lipase, lipoxygenase, and alcohol dehydrogenase, increased by 82.73%, 105.12%, and 487.86%, respectively, during the storage period of 1 life cycle of S. zeamais. Additionally, the fatty acid composition of S. zeamais-infested wheat was significantly altered (palmitic acid [1.10-fold], oleic acid [1.07-fold], and linoleic acid [0.95-fold]). Furthermore, 91 VOCs were identified in all wheat samples; then, multivariate statistical analyses categorized these samples into 4 groups: uninfested, longer storage, lightly infested, and heavily infested. Moreover, 31, 26, and 45 potential VOCs were identified to distinguish uninfested wheat from those in the other 3 groups. These results demonstrated that S. zeamais infestation induces an elevation in lipid-related enzymatic activities, which potentially leads to a decrease in lipid content alongside the production of specific VOCs (undecan-4-olide, heptaldehyde, and 2-nonenal). These findings provide novel insights for rapidly identifying grains infested by hidden pests and effectively managing these pests during grain storage.

Particle Size Effect of Piper guineense in the Control of the ‘Sitophilus zeamais Motchulski’ on Maize

Sitophilus zeamais is perhaps the most important storage insect pest of maize. The negative health implication of synthetic pesticides necessitates research into botanicals. We investigated the efficacy of ground Piper guineense (particles sizes 150, 300, 600, 1180, and 2360 µm) in controlling S. zeamais. The botanicals were compared with pirimorphos methyl and control (untreated seeds). Completely Randomized Design was used with three replications. Each treatment was infested with 20 adult weevils. Weevils were withdrawn after 14 days and the experiment was observed for another 38 days to count emerged adult weevils, numbers of damaged grains and exit holes on seeds, and determine loss in seed weight. Progressive efficacy and significant differences were observed among the botanicals and Pirimorphos methyl from four days after treatment application (DAT) to 14 DAT (90%, 100%, 100%, and 46.67%for Pirimorphos methyl, 150, 300, and 2360 µm of Piper respectively) as the particle size decreases. Piper of 150 and 300 µm particle sizes produced no new adult weevil and no seed weight loss at 52 DAW compared to others. The efficacy of piper at different particle sizes from 4 DAT showed that graduating piper particle size has significant effects on its insecticidal activity. It was concluded that ground piper of particle size 150µm is the most effective and is therefore recommended for effective control of maize weevils in storage.

Bioinsecticide textile bags for control of maize weevil during grain storage

The loss of stored grains due to the activity of insects is one of the main problems in maize production. The maize weevil, Sitophilus zeamais, is one of the major pests found in storage systems. We developed and evaluated the insecticidal efficiency against S. zeamais of three different bioactive fabric bags (cotton, polypropylene, and fibranne) loaded with latex paint-based formulation and pulegone, alpha-methly-trans-cinnamaldehyde, and a mixture of both compounds (at 24 and 48 h of exposure). Additionally, we determined the phytotoxicity of these formulations on maize grains and the release from the bags of the formulation with pulegone, that is, the amount of pulegone that is emitted from the bags. We found that at 24 h of exposure pulegone (1%) fibranne and cotton bags (26.71% and 15.81% respectively) were more effective against weevils than pulegone (1%) polypropylene (5.34%). The bags painted with the pulegone formulation at higher concentrations (at 2% and 3%) were effective, regardless of the fabric type used (cotton, polypropylene, or fibranne fabrics). The formulations with pulegone were not phytotoxic. Moreover, cotton bags showed the highest release of pulegone. These results are of interest because cotton bags painted with formulations based on pulegone-paint could serve as a potential tool for controlling the maize weevil in a grain storage system, such as in small storage in sacks or silo-bags.

Olfactory Preferences of Sitophilus zeamais to Cereal- and Legume-Based Pasta.

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.

Biocontrol potential of entomopathogenic nematodes against the grey maize weevil Tanymecus dilaticollis (Coleoptera: Curculionidae) adults.

The grey maize weevil, Tanymecus dilaticollis, is a polyphagous species, which is among the most important pests of maize in Southeastern Europe. The efficacy of commercial products with two species of entomopathogenic nematodes (EPNs), Steinernema carpocapsae and Heterorhabditis bacteriophora, was investigated against adults of the grey maize weevil under laboratory conditions. Nemastar®, containing S. carpocapsae was more effective on T. dilaticollis adults than Nematop® containing H. bacteriophora, when applied uniformly to the surface of the soil, on Petri dishes containing T. dilaticollis adults. Results showed that S. carpocapsae rates of 83-333 infective juveniles/adult caused > 94% mortality in T. dilaticollis adults, whereas H. bacteriophora caused 27-61%, adult mortality, after exposure of insects to the commercial products of EPNs for 15days. The infection rates of EPNs increased with concentration applied and ranged from 70-83% and 19-64% for Nemastar® and Nematop®, respectively. Subsequent field and semi-field tests were conducted with Nemastar® (application rate of 50 million S. carpocapsae per 100m2) in maize crops with biological (mycoinsecticide Naturalis®, biofungicides and fertilizers) and chemical seed treatment (Gaucho® FS 600; active ingredient: imidacloprid) in Knezha, Bulgaria. Nematodes were found only in the dead specimens, in open plots and cages sprayed with the commercial nematode product. Nematode sprayings contributed for higher maize yields in the open maize plots in the fields with different seed treatments. We suggest that the use of powder formulation of S. carpocapsae in combination with biologically treated maize seeds can contribute to minimize the use of chemical insecticides against the grey maize weevil. The results obtained can be used as a base to further tests to ascertain the efficacy of EPNs products before they can be recommended for use in the integrated approach to T. dilaticollis management.

Determination of chemical composition and insecticidal potential of leaf essential oil of Mentha piperita L.

Pulverised fresh Mentha piperita leaves was subjected to hydrodistillation for three hours in a Clevenger-type apparatus. The oil obtained was characterised using Gas Chromatography-Mass Spectrometry (GC-MS) and also evaluated for insecticidal activity on Callosobruchus maculatus (bean weevils) and Sitophilus zeamais (maize weevils). The oil afforded a yield of 0.78% (w/w). A total of 39 compounds were identified from their mass spectra representing 98.9% of the oil. The classes of compounds identified revealed predominance of oxygenated monoterpenoids (72.4%), hydrogenated monoterpenoids accounted for 6.0%, hydrogenated sesquiterpenoids and oxygenated sesquiterpenoids constituted 12.2 and 4.0% respectively. Other non-terpenic compounds detected in the oil accounted for 4.3% of the total oil. The most abundant compound was menthol (40.4%), other major compounds identified were menthone (12.3%), menthofuran (9.2%), 1, 8-cineole (5.6%) and limonene (5.5%). The percentage mortality of between 68-94.5% and 65-90.2% were recorded for bean weevils and maize weevils respectively after exposure to 10µl essential oil vapour in fumigation chambers for 6, 12, 18 and 24 hours. The insecticidal activity of the oil compared favourably with that of standard insecticide and so can be used to formulate an alternative insecticide from botanical source.

Efficacy of fumigant compounds from essential oil of feverfew (Chrysanthemum parthenium L.) against maize weevil (Sitophilus zeamais Mots.): Fumigant toxicity test and in-silico study

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. GC-MS 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, b-farensen, bornyl-tiglate, g-terpinene, p-cymene, bornyl-acetate, bornyl-isovalerate, terpinen-4-ol, trans-chrysanthenyl-acetate and a-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.&#x0D; KEY WORDS: Essential oil, Fumigants, Insecticides, Binding affinity, Maize weevil&#x0D; Bull. Chem. Soc. Ethiop. 2024, 38(2), 457-472. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v38i2.13

The distribution of insect pests and the associated loss of stored sorghum in the Kena district of Konso Zone, South-Western Ethiopia.

Sorghum is a staple crop grown in the poorest and most food-insecure regions of Ethiopia. But storage insect pests are its key constraints that have been causing considerable loss. Accordingly, an assessment of the prevalence of insect pests and the associated loss of sorghum stored under farmers' traditional storages was done in randomly selected major sorghum-growing kebeles of Kena District using a nested design between November 1, 2019 and December 30, 2020. It was conducted through the sampling of one kg of grain from a total of 360 randomly selected farmers' storages. Pests' abundance was determined by dividing the total number of individual species by the total number of samples. A count and weight method was used to estimate percent grain damage and weight loss by pests. Sitophilus zeamais, Sitophilus oryzae, Sitotroga cereallella, Tribolium castaneum, Tribolium confusum, Cryptolestes ferrugineus, Cryptolestes pusillus, Rhyzopertha dominica, and Plodia interpunctella were the pests identified from grain samples. When compared to mid-latitude, where they were found in the range between 2.36± 0.21 and 17.50±0.98 mean number of species, all of these pests had a considerably (p < 0.05) larger distribution in low-land kebeles, where they predominated in the range between 5.44±2.00 and 23.61±1.75 amean number. During the nine-month storage period, the degree of pest infestation, percentage of grain damage, and weight loss were significantly (p < 0.05) higher in the bamboo bins when no management measures were implemented in the mid-land and low-land kebeles, respectively, than in the barn. Consequently, bamboo bin storage was considered ineffective for sufficient sorghum grain protection against pests and the associated loss over a longer storage period. But barn storage and the use of cultural pest management practices performed better in protecting stored sorghum from pests. Therefore, improving the bamboo bin storage method is needed to improve its grain protection efficacy.

Potential of Solid Gel Formulation of Kaffir Lime Peel Extract Against Postharvest Pest Sitophilus Zeamais on Stored Rice

Maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) is a primary pest on maize, rice, wheat, sorghum, and other cereal grains. The purpose of this study was to determine the effectiveness of using kaffir lime peel extract in solid gel formulation as a plant-based insecticide. This study used five treatments, untreated (control), 0.5%, 1%, 1.5%, and 2%. The results of this study are the treatments tested had effects on adult mortality and repellency. The 2% concentration showed the highest adult mortality and repellency. The major volatile organic compounds contained in kaffir lime peel were α-fernesene, α-sinensal, D-citronellol, and citronellal.

Evaluation of Insecticidal Activity of Bioactive Compound Isolated from Seeds of Psoralea corylifolia L. on Maize Seeds Deteriorating Insect (Sitophilus zeamais M.)

Evaluation of Insecticidal Activity of Bioactive Compound Isolated from Seeds of Psoralea corylifolia L. on Maize Seeds Deteriorating Insect (Sitophilus zeamais M.)

Effectiveness of bagasse and rice straw ashes against postharvest pest, Sitophilus zeamais on maize seed

Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) is the main pest on maize seed in the storage. In general, postharvest pest control uses synthetic insecticides. However, the use of these synthetic insecticides causes insect resistance and negative impact on human health. This study aimed to determine the effectiveness of rice straw and bagasse ashes as inert dust in postharvest pest management of S. zeamais. This study was conducted at the Laboratory of Entomology, Faculty of Agriculture, Universitas Hasanuddin. This study used two treatments with four different doses i.e., 2, 4, 6, 8 g, and untreated (control). The results showed that complete (100%) of adult mortality at highest dose (8 g/kg seed) of bagasse ash in three days after infestation, while in the higher doses (6 and 8 g/kg seed) of rice straw ash killed 99.15%. The use of inert dust also causes typical symptoms in mortality in the form of wings coming out of the elytra, which is different from adult mortality without treatment.

Atividade inseticida e repelente do capim-limão nativo e exótico no gorgulho do milho

Corn crop, due to its easy adaptation to the most diverse agroecosystems, spreads throughout the different regions of the world, making it one of the most important agricultural crops. In this crop, pest insects stand out for causing losses both in the field and in warehouses. The application of essential oils can be an important technique to be investigated in the management of insects due to its known insecticidal activity and low risk to the environment. The objective of the work was to value the insecticide and repellent effect of essential oils of exotic lemongrass (Cymbopogon citratus) and native lemongrass (Elionurus sp.) for the management of maize weevil (Sitophilus zeamais (Mots., 1855, Coleoptera: Curculionidae)). The chemical analysis of the oils made by CG-MS showed that the chemical composition of the native and exotic lemongrass is similar, however, the exotic species presented a greater number of compounds. The essential oils of native and exotic lemon grass have efficiency on maize weevil mortality, and it is verified that the increase in the applied dose reflects in a reduction in the insect's exposure time for death to occur. The essential oil of both species showed repellent capacity at all times evaluated. Thus, it can be said that both species have the capacity and potential to be used in the management of corn weevil, and can be an alternative for smallhorders farmers and organic production.