Fumigant Activity Research Articles

Disposal of Used Fumigant Containers in Zambia

Fumigation involves the use of a highly toxic pesticide known as a fumigant, to kill target organisms under airtight conditions. After fumigation, the residual containers left are classified as hazardous wastes. Such wastes enter our environment owing to improper disposal of the containers and poses a huge threat to public health and the environment. This study assessed the methods of disposal of fumigant containers practiced in Zambia and the extent to which fumigators comply with Zambian environmental regulations. Both qualitative and quantitative data collection approaches were used and purposive sampling helped in establishing the fumigant package disposal sites. Data was collected from 15 districts along the line of rail, from Livingstone to Chingola. Participants constituted 25 fumigators and 50 assistants conducting fumigation in the 15 districts. Data from 25 questionnaires distributed to the fumigators was analyzed using the Statistical Package for Social Science (SPSS) version 20 alongside Excel 2010. The findings revealed that 68 % always buried the fumigant containers in a 1-meter-deep pit. However, through observations, 17 fumigators from the 15 districts disposed the containers on open surfaces despite being aware of the environmental regulations. On the other hand, the Zambia Environmental Management Agency visited only 48 % of fumigators’ premises. Only 21 % of fumigators were compliant with the law in their disposal methods while the remaining 79 % were non-compliant. Though fumigators were trained before engaging in fumigation activities, they took little useful action for safe disposal of fumigant containers. Findings in this study require immediate enactment laws that will help abolish unsafe disposal of fumigant containers in Zambia. Further, trained fumigators and not their assistants should conduct disposal of fumigant containers. The Zambia Environmental Management Agency should intensify their inspections combined with law enforcement and standard fumigant disposal protocols must be devised and made available to the fumigators.

Chemical Composition and Fumigant Activities of Essential Oils from Piper hancei Maxim against Tribolium castaneum (Herbst).

The present study aimed to analyze the chemical composition and fumigant toxicity of essential oils (EOs) isolated by hydrodistillation from Piper hancei Maxim. EOs extracted from the dry stems and leaves of P. hancei were analyzed by gas chromatography-mass spectrometry (GC-MS). The main compositions of the EOs were humulene (13.624 %), caryophyllene (13.319 %), nerolidol (12.507 %), naphthalene (8.525 %), ledol (6.694 %), caryophyllene oxide (6.404 %), and junenol (6.350 %). The fumigant toxicity of the EOs was tested in 7-14 day old adults of Tribolium castaneum. The LC50 of EOs and individual main compositions were calculated according to the mortality of insects at concentrations of 0, 16, 32, 64, 128, and 256 (μL/L air). The results showed that the EOs (LC50=322.52 (48 h) and 145.82 (72 h) (μL/L air)), caryophyllene (LC50=37.95 (48 h) and 26.53 (72 h) (μL/L air)), junenol (LC50=38.32 (48 h) and 20.33 (72 h) (μL/L air)), caryophyllene oxide (LC50=97.72 (48 h) and 65.22 (72 h) (μL/L air)), and humulene (LC50=104.50 (48 h) and 73.66 (72 h) (μL/L air)) have obvious fumigant activities against T. castaneum adults. The chemical composition of EOs from P. hancei was reported for the first time. The results indicated that the EOs of P. hancei had the potential to be developed as a natural insecticide for the control of T. castaneum adults.

Acute toxicity and repellent activity of essential oil from Atalantia guillauminii Swingle fruits and its main monoterpenes against two stored product insects

ABSTRACT The objective of this work was to analyze the essential oil from Atalantia guillauminii fruits in China and evaluate their chemical compositions, insecticidal and repellent activities against Tribolium castaneum and Lasioderma serricorne adults. The essential oil was obtained by hydro-distillation and its yield was 0.12% (V/W). All together 25 chemical compositions were identified by GC-FID and GC-MS, and the main chemical compositions were D-limonene (41.8%), β-pinene (10.9%) and selina-3,7(11)-diene (6.8%). The bioactivity of the obtained essential oil and its two main compositions (D-limonene and β-pinene) was investigated by fumigation, contact and repellent activity bioassay. The essential oil and its two main compositions all showed significant fumigant toxicity, contact toxicity and repellent activity against two target insects. These results suggest that the essential oil and its two main compositions have potential to be developed as natural insecticides and repellents for the control of stored product insect pests.

Methyl Benzoate Is Superior to Other Natural Fumigants for Controlling the Indian Meal Moth (Plodia interpunctella).

Simple SummaryGlobally, the Indian meal moth is an insect pest of stored goods and manufactured foodstuffs. Synthetic fumigants, such as phosphine and methyl bromide, are widely used agents to control this species. However, due to the development of resistance and increasing concern about the potential adverse effects of synthetic fumigants, it is now necessary to identify environmentally friendly alternatives. Naturally occurring compounds, such as essential oils (EOs), are perhaps the most promising alternative sources; many have been successfully used as active ingredients in contact-based control products, repellents, and fumigants. Methyl benzoate (MBe) is an environmentally friendly, food-safe, natural insecticide that offers a possible alternative to synthetic equivalents. Here, we evaluated the fumigant toxicity of MBe against adults of the Indian meal moth and found that it had great potential for the control of these insect pests in stored products.The Indian meal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is an insect pest that commonly affects stored and postharvest agricultural products. For the control of insect pests and mites, methyl benzoate (MBe) is lethal as a fumigant and also causes contact toxicity; although it has already been established as a food-safe natural product, the fumigation toxicity of MBe has yet to be demonstrated in P. interpunctella. Herein, we evaluated MBe as a potential fumigant for controlling adults of P. interpunctella in two bioassays. Compared to the monoterpenes examined under laboratory conditions, MBe demonstrated high fumigant activity using a 1-L glass bottle at 1 μL/L air within 4 h of exposure. The median lethal concentration (LC50) of MBe was 0.1 μL/L air; the median lethal time (LT50) of MBe at 0.1, 0.3, 0.5, and 1 μL/L air was 3.8, 3.3, 2.8, and 2.0 h, respectively. Compared with commercially available monoterpene compounds used in pest control, MBe showed the highest fumigant toxicity (toxicity order as follows): MBe > citronellal > linalool > 1,8 cineole > limonene. Moreover, in a larger space assay, MBe caused 100% mortality of P. interpunctella at 0.01 μL/cm3 of air after 24 h of exposure. Therefore, MBe can be recommended for use in food security programs as an ecofriendly alternative fumigant. Specifically, it provides another management tool for curtailing the loss of stored food commodities due to P. interpunctella infestation.

Fumigant toxicity of some essential oils against Red Flour Beetles, Tribolium castaneum (Herbst) and its safety to mammals.

Fumigant activities for three essential oils; Garlic oil (Allium sativum L); Chili pepper (Capsicum annuum L.) and Nigella (Nigella sativa L.) were assessed at different concentrations against the adult and 20-days old larval stages of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) in the laboratory. The accumulative mortality was observed at different exposure periods (3, 5 and 7 days). The residual effect of garlic oil that was the effective oil, on the treated wheat grains was evaluated with respect to histological changes in the liver, kidney, and stomach of rat fed on this treated wheat. The results showed that the mortality rates of treated stages increased with increasing the time of fumigation treatment. Moreover the highest essential oils toxicity at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (126, 53, and 47 mg/L air) for adult stage and were (79, 62, and 41 mg/L air) for larval stage, respectively in the case of Garlic oil treatment. While, the lowest essential oils effective was Nigella oil at the Median lethal concentration (LC50) values for exposure periods (3, 5 and 7 days) to fumigation were (3594, 629, and 335 mg/L air) for adult stage and were (1040, 416, and 227 mg/L air) for larval stage, respectively. The toxicity effect of various essential oils against adults and larvae of T. castaneum at the LC50at 7 days fumigation could be arranged in descending order as follows: Garlic oil, Chili pepper oil, and Nigella oil. The histological changes showed that the organs slightly affected at the fumigation for 3 days. It may be concluded that the garlic essential oil is the good effective fumigant to control T. castaneum in the stored products and it recommended that the fumigation period does not exceed 3 days. The garlic essential oil has the potential for applications in IPM programs for stored-grain pests because of its high volatility and fumigant activity and its safety.

Bioassay Essential Oils on Tribolium castaneum and Tribolium confusum (Coleoptera: Tenebrionidae)

Background: Tribolium confusum and Tribolium castaneum are pests spread inside the stores and homes. These pests infest stored grains and many others seeds in the stores and bakery. These controlled by insecticides. The essential have a promising research results in controlling these pests and decreasing the insect infestations. The natural essential oils have a low effect on the human, non-target insects, and do not pollute the environments. This research is an alternative approach to natural control these two stored product pests. Methods: Four essential oils namely, Lantana camara, Acorus calamus, caraway oil and Ammi majus were estimated on two stored product insects T. confusum and T. castaneum. Encapsulation method by the technology of polymerization was followed. The nano oils at 0.5% were estimated on the 3rd larval instars. Percentages of accumulative mortality were calculated after seven days of the experiments. The effect of nano-oils on oviposition experiments made by spraying two grams of foams of the tested oils and their nano formulations mixed with 100 gram of wheat. Results data obtained detected that, the Percentage of larval mortality increase by increasing the concetrations for both insects T. confusum and T. castaneum. T. confusum tested larvae were more susceptible to the treatments than T. castaneum larvae. Nano A. majus oil showed a stronger effecte than that L. camara or A. calamus oil. Adult emergence percent and fecundity showed a highly decreasing after treatments with nano-oil L. camara, A. calamus, A. majus oils under storage conditions, compared to those of the controls or non-nano-oils. The results suggested that nano A. majus can be used as a valuable tool in pest management programs of T. confusum and T. castaneum Conclusion: The results of this work indicate that some essential oils might be helpful management of pests in the stores because of their fumigant and odor action. Essential oils of plant origin contain active ingredients which are effective against many insects. Nano formulations of essential oils, through controlled release, prevent speed violate and decay and, also increase the stability of the oils. Treated foam, using L. camara, A. majus, caraway, and A. calamus oils gave protectthe wheat seeds from two pests infestations.

Vapour-phase efficacy of selected essential oils individually and in combination against Aspergillus flavus, A. niger, Fusarium proliferatum, and Curvularia lunata

Grain storage plays a crucial role in ensuring food security to Thai farmers so sustainable protection methods against deleterious microorganisms, such as fungi, are necessary. Essential oils (EOs) have demonstrated broad-spectrum fumigant antifungal activity against most storage fungi that are problematic in Thailand. Four storage fungi (Aspergillus flavus, A. niger, Curvularia lunata and Fusarium proliferatum) were isolated from dried rice and corn grains (stored for at least six months). EOs were extracted by hydrodistillation from clove buds (Syzygium aromaticum), fruit peel and leaves of makrut lime (Citrus hystrix), eucalyptus leaves (Eucalyptus sp.) and lemongrass stems (Cymbopogon citratus). The fungi inoculated on PDA in plastic cups were exposed to each EO vapour originating from paper disc attached in the lids in an inverted position. The minimum inhibitory concentration (MIC) for each EO was determined. Selected MICs were combined in a binary manner and similarly tested against the fungi. Fractional inhibitory concentration indices (FICI) were determined for each combination. Lemongrass and makrut lime leaf EOs were the most effective with MICs of 0.09 µL/mL against Curvularia lunata and 0.19-0.28 µL/mL against A. flavus, A. niger and F. proliferatum. Eucalyptus oil produced the least effective vapour (MIC 0.56-0.74 µL/mL) against all tested pathogens. A combination of lemongrass and makrut lime leaf EOs was partially synergistic against A. niger (FICI=0.75) but was fully synergistic against the other three fungi tested (FICI=0.5). The EOs from lemongrass and makrut lime leaf have potential to suppress the growth of the four grain-storage fungi tested.

Investigation of chemical composition of Ailanthus Altissima (Mill.) Swingle

Ailanthus altissima (Mill.) Swingle is a source of various classes of biologically active compounds. This determines its phytotoxic, fumigant, antioxidant, antimicrobial, and anthelmintic action. However, the scientific literature lacks information about its chemical composition and prospects for use in medicine.The aim of the work. The study of the qualitative and quantitative composition of Ailanthus altissima (Mill.) Swingle leaves and fruits by GS / MS analysis. Identify possible future prospects for the use of the test plant in medical practice as a source of potential medicines.Materials and research. The object of research is Ailanthus altissima leaves and fruits. The tincture was obtained by maceration, the raw material was extracted with methyl alcohol at room temperature for 10 days.Qualitative and quantitative determination of active compounds was carried out on a gas chromatograph “Agilent 7890B GC System” (Agilent, Santa Clara, CA, USA) with mass spectrometric detector “Agilent 5977 BGC/MSD” (Agilent, Santa Clara, CA, USA) and chromatographic column DB-5ms (30 m × 250 μm × 0,25 μm).Results. In the course of the study, 35 biologically active compounds were identified in the leaves and 41 – in the fruits of Ailanthus altissima. It has been found that the main components of leaves are phytol – 21.15 %, hexadecanoic acid – 8.53 %, α-tokospiro A – 8.14 %, 2-C-methyl-myo-inositol – 7.78 %; the main components of fruits are α-tocopherol – 13.35 %, vaccenic acid – 11.42 %, butyric acid 2-ethylhexyl ester – 9.77 %. α-tocopherol is known for its antioxidant and anti-inflammatory effects.Conclusions. It is for the first time when chemical composition of Ailanthus altissima leaves and fruits was established with GS/MS. 35 biologically active compounds in leaves and 41 in fruits of the studied object were identified. The main components of the leaves are phytol – 21.15 %, hexadecanoic acid – 8.53 %, α-tocospiro A – 8.14 %, and these of the fruits comprise α-tocopherol – 13.35 %, vaccine acid – 11.42 %, 2-ethylhexyl ester of butanoic acid – 9.77 %. The results can be used to create new potential antimicrobial, antioxidant and anti-inflammatory drugs.

Target verification of allyl isothiocyanate on the core subunits of cytochrome c oxidase in Sitophilus zeamais by RNAi

Allyl isothiocyanate (AITC) is a volatile organic compound with a potent insecticidal activity to the stored-grain pest Sitophilus zeamais Motschulsky, which severely damages grain storage and container transport worldwide. Our previous study showed that mitochondrial complex IV was the primary target of AITC in adult Sitophilus zeamais. To further verify the targets of AITC, we employed RNA interference (RNAi) by using double-stranded RNA (dsRNA) to knockdown three core subunits of cytochrome c oxidase (COX)-I, -II and -III in 18-day-old larvae prior to their exposure to AITC to detect susceptibility changes. The susceptibility of dsRNACOX-I and -II injection treatments to AITC significantly increased at 72 h while the mortality reached up to 85.56% and 67.78%, respectively, and dsRNACOX-I and dsRNACOX-II injection showed the same subcellular structural characteristics showing vacuolization and vague mitochondrial cristae and decrease of COX activity during AITC fumigation treatment, suggesting the potential of COX-I and COX-II as the targets of AITC. High mortality reached up to 75.55%, 71.88% and 82.22%, respectively, and the phenotype of larvae turning from milky white to dark brown in the thorax and death eventually was confirmed after dsRNACOX-I, -II and -III injection. COX-I and -II were elucidated as the potential targets of AITC and dsRNACOX-I, -II and -III have the potential to be developed into nucleic acid pesticides for their robust lethal effects and are worth pursuing for improving AITC fumigation activity in Sitophilus zeamais control. © 2020 Society of Chemical Industry.

Efficacy of Ocimum tenuiflorum essential oil as grain protectant against coleopteran beetle, infesting stored pulses.

In the present investigation, essential oil (EO) of Ocimum tenuiflorum and its principal constituent (eugenol) was evaluated for its toxicity and mode of action against Callosobruchus maculatus. Furthermore, fumigant toxicity and germination studies on the application of O. tenuiflorum EO and eugenol against C. maculatus on different pulses was also studied. Fumigant activity studies revealed that EO toxicity was significantly (p < 0.05) influenced by concentration and exposure time. In fumigant toxicity assay without food, O. tenuiflorum EO and eugenol showed LC50 value of 278.6 and 256.5µL/L air, respectively, at one hour exposure. Further, O. tenuiflorum EO displayed fumigant toxicity via inhibiting acetylcholinesterase activity. Pulses treated with O. tenuiflorum EO showed 70% of C. maculatus mortality at 250µL/L air concentration after 24h. Furthermore, these treatments didn't affect the seed viability of the pulses tested. Hence, the application of O. tenuiflorum EO has potential scope as a botanical insecticide.

Fumigation Activity against Phosphine-Resistant Tribolium castaneum (Coleoptera: Tenebrionidae) Using Carbonyl Sulfide.

Simple SummaryPhosphine is one of the most widely used fumigants for the control of stored grain pests in quarantine. However, PH3 resistance to many stored pests has been reported. In this study, the fumigation activity of carbonyl sulfide was researched as an alternative fumigant to control PH3-resistant pests. In PH3 treatment, there was a clear difference in the fumigation activity of domestic strain Tribolium castaneum and resistance strain T. castaneum, but both the d- and r-strains of T. castaneum showed similar results in the carbonyl sulfide (COS) treatment. Furthermore, both PH3 and COS showed no significant difference in fumigation activity in Oryzaephilus surinamensis.Phosphine resistance is occurring among stored-grain pests worldwide. This study investigated the fumigation activity of phosphine (PH3) and carbonyl sulfide (COS) against domestic strain (d-strain) Tribolium castaneum, resistance strain (r-strain) T. castaneum and Oryzaephilus surinamensis. All developmental stages of the pests were exposed to two fumigants (PH3 and COS), and the fumigation activity according to the dose and exposure time was evaluated in a 12-L desiccator and 0.5 m3 fumigation chamber. The rice sorption rate and quality following exposure to thetwofumigants were evaluated. The mortality was 2.9% in r-strain T. castaneum, 49.5% in d-strain T. castaneum and 99.2% in O. surinamensis when 2 mg/L PH3 was used in a 12-L desiccator for 4 h. However, all pest developmental stages showed 100% mortality after 24 h of exposure in the 0.5 m3 fumigation chamber, except for the r-strain T. castaneum. A mortalityof 100% was observed in all of the r-strain T. castaneum developmental stages at an exposure time of 192 h. For COS applied at 40.23 mg/L and 50 g/m3 in the 12-L desiccator and the 0.5 m3 fumigation chamber, respectively, 100% mortality was observed across all developmental stages regardless of species and strain. The sorption of COS was 10% higher than that of PH3, but there was no significant difference in rice quality compared to that in the control. Therefore, this study suggests that COS can be used for controlling T. castaneum resistant to PH3.

Insecticidal and behavioral effects of some plant essential oils against Sitophilus granarius L. and Tribolium castaneum (Herbst)

Insecticidal, repellent and fumigant activities of Rosemary [Rosmarinus officinalis (Lamiaceae)], Daphne [Laurus nobilis (Lauraceae)], Echinacea (Echinacea purpurea (Asteraceae), Marjoram [Origanum majorana (Lamiaceae)], Basil [Ocimum basilicum (Lamiaceae)] and Fennel [Foeniculum vulgare (Apiaceae)] extracts were tested against Sitophilus granarius (Col.: Curculionidae) and Tribolium castaneum (Col.: Tenebrionidae) under laboratory conditions. The composition of essential oils extracted from the plants was also determined. Eucalyptol and Terpinyl acetate were the main components of Daphne oil. Similarly, the main components of Basil oil were Methyl cinnamate, Linalool and Eucalyptol, whereas Camphor and Eucalyptol were the main constituents of Rosemary oil. Likely, γ-Terpinene and β-Terpineol were the main components of Marjoram oil, while Estragole was the main component in Fennel oil. The β-Cubebene and Caryophyllene were the main components of Echinacea oil. Echinacea and Basil oils exhibited high contact toxicity against S. granarius. Basil oil caused 99.59% mortality of S. granarius 24 h after application, whereas Echinacea oil caused 99.59% mortality 72 h after application. In single-dose fumigant toxicity assays, Rosemary oil exhibited 58.41% fumigant activity against S. granarius after 24 h, whereas Fennel oil indicated 100% fumigant toxicity against T. castaneum. All essential oils showed repellent effects against both the pests. The essential oils caused 34.12–95.29% decrease in the progeny production of F1 generation of T. castaneum, while the decrease in the F1 generation of S. granarius ranged between 84.27 and 98.88%. It is concluded that essential oils of Fennel, Rosemary, Echinacea and Basil could potentially be used for the control of studied stored grain pests.

QSAR models for the fumigant activity prediction of essential oils

The Quantitative Structure-Activity Relationships (QSAR) theory, which allows predicting the insecticidal activity of chemical compounds through calculations from the molecular structure, is applied on 23 essential oils composed of 402 structurally diverse compounds at different chemical compositions. A large number of 114,871 conformation-independent molecular descriptors are computed through different types of freely available open-source programs. Mixture descriptors are calculated based on molecular descriptors of the essential oil components and their composition. The best resulting three-descriptor linear regression models are established through the Replacement Method variable subset selection approach. The results obtained in the present work are interesting for predicting the fumigant activity of these essential oil complex mixtures, by means of simple non-conformational QSAR models.

Volatile chemical composition of Colombian Piper gorgonillense Trel. &amp; Yunck. essential oil and its repellent and fumigant activity against Tribolium castaneum Herbst

Essential oils (EOs) are mixtures of volatile organic compounds, mostly terpenes, from the secondary metabolism of plants. These oils exert various activities on insects that damage crops and cause losses worldwide for the economy and agriculture. Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) is one of the main pests causing the loss of a large amount of stored food. The objective of this study was to evaluate the volatile chemical composition of the essential oil from Piper gorgonillense Trel. &amp; Yunck. and its repellent and fumigant activity on T. castaneum. The volatile composition was determined with gas chromatography coupled to mass spectrometry. The majority compounds found in the EO were b-caryophyllene (28.7%), a-copaene (13.5%), and d-cadinene (7.3%). The repellency percentages obtained were 78 and 90% at a concentration of 1% with exposure times of 48 and 72 hours, respectively. The fumigant activity refers to the insecticidal action that an essential oil vapor can have without coming into direct contact with insects; this was 100% at a concentration of EO 350 µg mL-1. The results showed that the P. gorgonillense EO had repellent and insecticidal properties for the biological control of T. castaneum.

Relationship Between The Presence Of Bromide Ion InThe Blood And Disturbance Of Body Balance In The Fumigator At Tanjung Emas Port, Semarang

Introduction Tanjung Emas Port Semarang is one of the ports that organizes fumigation activities. Fumigation measures in the context of controlling pests or insects on conveyances and their cargo are very risky of exposure to methyl bromide fumigants, one of which is disruption of body balance. The purpose of this study was to determine the relationship between the presence of bromide ions in the blood and disturbances in body balance in the fumigator. Methods: This study was an observational study with a cross sectional study design. The number of samples was 38 fumigators with the criteria of being willing to be respondents aged 19-55 years with the sampling technique method with saturated samples. The method of examining bromide ions in the blood is through a qualitative inorganic analysis test, while the method of measuring body balance disorders uses the Romberg test method (sharpened). Results: The results of data analysis showed that laboratory tests of the bromide ion in the fumigator blood were positive for 22 people or 57.9%. The compliance factor for wearing Personal Protective Equipment and the frequency of fumigation were not related to the presence of bromide ions in the fumigator blood. Measurement of body balance disorders showed positive 26 people or 68.4% and 12 people or 31.6% negative. Analysis of the variables of the presence of bromide ions in the blood with disturbed body balance in the fumigator using the ChiSquare test (X2) obtained a p value of 0.002 less than α (0.05). Conclusion: There is a relationship between the presence of bromide ions in the blood and disturbances in body balance in the fumigator at Tanjung Emas Port, Semarang

Fumigant and feeding deterrent activity of essential oils against Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae)

Abstract. Ikawati S, Himawan T, Abadi AL, Tarno H. 2020. Fumigant and feeding deterrent activity of essential oils against Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae). Biodiversitas 21: 4301-4308. This study aimed to determine the fumigant and antifeedant activity of some plant essential oils against Cryptolestes ferrugineus. Essential oils were extracted from cinnamon (Cinnamomum verum), kaffir lime (Citrus hystrix), citronella grass (Cymbopogon nardus), zodea (Euodia suaveolens), and clove (Syzygium aromaticum). The extraction used the maceration method with n-Hexane as a solvent. The results of the experiments showed that all essential oils have fumigant toxicity. Fumigant toxicity of kaffir lime, citronella grass, zodea, and clove oil; eggs and pupae were more susceptible than adults and larvae, while for cinnamon, pupae and adults were more susceptible than eggs and larvae. Median Lethal Concentration (LC50) of all essential oils for eggs larvae, pupae, and adults respectively, for cinnamon were 17, 24, 9, and 12 ppm, for kaffir lime were 12, 17, 8 and 15 ppm, however, on citronella grass were 11, 22, 8, and 14 ppm, for zodea were 16, 22, 10 and 20 ppm, for clove were 11, 24, 7 and 14 ppm. The fifth essential oils showed antifeedant activity in a no-choice test against C. ferrugineus adults. Also, the fifth essential oils significantly reduced the relative growth rate (RGR), relative consumption rate (RCR), and food utilization (ECI) of C. ferrugineus adults. It shows that the essential oils have great potential as one of the storage pest control components.

Evaluation of the Insecticidal Activities of α-Pinene and 3-Carene on Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae).

Simple SummaryIn order to assure food security, proven postharvest pest management tools are needed to secure grains and processed food from insect infestations. Plants and plant products have over the years been proven to possess great insecticidal properties. Farmers in Cameroon use cypress leaves (Cupressus sempervirens) as pesticide against the maize weevil (Sitophilus zeamais). Two pure compounds (α-Pinene and 3-Carene) from cypress were tested against the maize weevil for contact and fumigant toxicities. Both compounds demonstrated efficacies against both adult and immature weevils. These compounds did not change the color of the treated stored maize and could be exploited as novel maize insecticides.Pest management in most sub-Saharan subsistence agriculture involves mainly the use of botanicals that are either applied as powders, solvent extracts, ash or essential oils. Two hydrogenated monoterpenes (α-pinene and 3-carene) from Cupressus sempervirens were tested against Sitophilus zeamais in the laboratory to evaluate the contact and fumigation effects on the mortality of adult and immature weevils, progeny production, and grain damage. Contact toxicity of the terpenes was investigated at these concentrations: 0.08, 4, 8 and 12 ppm (terpene/maize), while fumigant action was studied at the following doses: 1, 2, 3, and 4 ppm. The results indicate that insecticidal effects were concentration-dependent since mortality increased with dosage and exposure periods. After a 14-day exposure period at the concentration of 12 ppm of α-pinene and 3-carene/grain, more than 98% mortality of the mature weevils was observed at concentrations of 4.1333 and 1.642 ppm respectively and progeny production was reduced by 98% and 100%, respectively. When α-pinene and 3-carene were applied as fumigants, LC50s (lethal concentrations that generate 50% mortality) of 1.402 and 0.610 ppm were obtained after 24 h of exposure, respectively. At concentrations above 3 ppm, both monoterpenes acted as repellents to weevils and reduced grain damage by 80%. Both monoterpenes inhibited the development of immature stages of the weevil and reduced progeny by up to 94%. These compounds are very promising and effective and could be exploited as novel phytoinsecticides against the maize weevil.

Efficacy of nano-formulated certain essential oils on the red flour beetle Tribolium castaneum and confused flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae) under laboratory and storage conditions

AbtractBackgroundThe confused flour beetles Tribolium confusum (Jacquelin) and red flour beetle Tribolium castaneum (Herbst) are widespread insects found in the stores and homes that attack many stored foods in several commodities. They are controlled by synthetic chemical insecticides. The natural oils give good results in controlling these pests and decreasing its infestations. The natural essential oils have a low effect on the human, non-target insects, and do not pollute the environments. This research is an alternative approach to naturally control these two stored product pests.MethodsNano-formulations of four essential oils, namely, coriander, black seed, caraway oil, and Janesville were tested against T. confusum and T. castaneum in the laboratory and stored conditions. Encapsulation method by the technology of polymerization was followed. The nano-oils were tested at the concentrations of 0.5% against the 3rd larval instars. Cumulative percentages of mortality was determined after 7 days of the first applications. The effect of nano-oils on oviposition was carried out by spraying 2 g of foams of the tested oils and their nano-formulations mixed with 100 g of wheat.ResultsThe results obtained showed that the percentage of larval mortality of T. confusum and T. castaneum increased with an increase in the treatment concentrations. Larvae of T. confusum were more susceptible to the treatments than T. castaneum larvae. Nano Janesville oil was more effective than that of coriander or black seed oil. Fecundity and adult emergence percentage are highly suppressed by nano-formulations of coriander, black seed, or Janesville oils under storage conditions, compared to those of the controls or non-nano-oils.The results suggested that nano Janesville can be used as a valuable tool in pest management programs of T. confusum and T. castaneumConclusionThe results of this work indicate that some essential oils might be helpful management of pests in the stores because of their fumigant and odor action. Essential oils of plant origin contain active ingredients that are effective against many insects. Nano-formulations of essential oils, through controlled release, prevent rapid vaporization and degradation and increase the stability of the oils. Treated foam, using coriander, Janesville, caraway, and black seed (habat al Baraka) oils, gave protection against the red flour beetles Tribolium castaneum and confused flour beetle Tribolium confusum.

Essential oil composition and insecticidal activity of Satureja boissieri against Sitophilus granarius (Coleoptera:Curculionidae) and Spodoptera littoralis (Lepidoptera: Noctuidae)

In the scope of this study, we have investigated fumigant and contact toxicity effects of Satureja boissieri Hausskn. ex Boiss. essential oil against Sitophilus granarius L. (Coleoptera: Curculionidae) and Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae). The fumigant and contact toxicity experiments were carried out with the adults of Sitophilus granarius whereas the contact toxicity experiment was carried out with the 3rd, 4th and 5th larvae of S. littoralis. Also, various fractions of S. boissieri essential oil were investigated for fumigant activity against S. granarius. In fumigant toxicity studies, the highest activity was obtained at 36 hours with a dose of 0.1 μl/ml with a 100% mortality rate. Fractions of the essential oil had significant fumigant activity on S. granarius (100% fumigant activity at 0.1 μl/ml). Contact toxicity of 100 μl/ml essential oil on the 3rd and 4th larval stage of S. littoralis, was determined to be 100%, however, on the 5th larval stage it was 90.17%. The activity at 25 μl/ml dose was 71.12% in the 3rd larval stage whereas the activity remained very low (6.39- 22.20%) in other larval stages. These results indicated that essential oil of S. boissieri have significant potential which merits to be studied further in possible applications as fumigant and contact insecticide in the control of S. granarius and S. littoralis.

Reactive oxygen species mediated-antifungal activity of cinnamon bark (Cinnamomum verum) and lemongrass (Cymbopogon citratus) essential oils and their constituents against two phytopathogenic fungi

To find new and safe type of control agents against phytopathogenic fungi, the fumigant antifungal activity of 10 plant essential oils and constituents identified in cinnamon bark (Cinnamomum verum) and lemongrass (Cymbopogon citratus) essential oils was investigated against two phytopathogenic fungi, Raffaelea quercus-mongolicae and Rhizoctonia solani. Among plant essential oils, cinnamon bark and lemongrass essential oils showed 100% inhibition of R. quercus-mongolicae and R. solani at 5 mg/paper disc, respectively. Among test constituents, salicylaldehyde, eugenol, and hydrocinnamaldehyde showed 100% inhibition of growth of R. quercus-mongolicae at 2.5 mg/paper disc. Neral, geraniol, geranial, trans-cinnamaldehyde, methyl cinnamate, isoeugenol, and methyl eugenol exhibited >80% inhibition of growth of R. quercus-mongolicae at 2.5 mg/paper disc. Neral, geranial, trans-cinnamaldehyde, hydrocinnamaldehyde, and salicylaldehyde showed 100% inhibition of growth of R. solani at 2.5 mg/paper disc. A fumigant antifungal bioassay of artificial blends of the constituents identified in cinnamon bark and lemongrass essential oils indicated that trans-cinnamaldehyde and geranial were major contributors to the fumigant antifungal activity of the artificial blend. Confocal laser scanning microscopy images of fungi treated with cinnamon bark and lemongrass essential oils, trans-cinnamaldehyde, neral, and geranial revealed the reactive oxygen species (ROS) generation and cell membrane disruption.