Oviposition Deterrent Activity Research Articles

Deterrent Activity of Natural Products on Two Spotted Spider Mite <i>Tetranychus urticae</i> Koch

The feeding inhibition and oviposition deterrent activity of natural products were evaluated under laboratory conditions against Tetranychus urticae Koch. Mite feeding specks in the treatments varied from 61.3 to 428 at concentrations ranging from 0.625 to 40%. Darekastra and fermented buttermilk outperformed others to result in reduced number of feeding specks with increase in concentration. The feeding inhibition index for all the products was negative suggesting that these have varied level of inhibition. Cow urine, Darekastra, fermented buttermilk and Tamarlassi were found to effectively reduce the oviposition by mite. The oviposition deterrence index exhibited both attractiveness and repellent activity of natural products. Cow urine, Darekastra and fermented buttermilk proved as potent acaricides against T. urticae under both the deterrence parameters.

Oviposition Deterrent Activity of Fungicides and Low-Risk Substances for the Integrated Management of the Olive Fruit Fly Bactrocera oleae (Diptera, Tephritidae).

Simple SummaryThe olive fruit fly Bactrocera oleae is a very common pest infesting olive orchards wherever they are cultivated, representing the greatest threat to olive production and oil quality. Although broad-spectrum insecticides are often used to protect olive crops against B. oleae, there is increasing concern about their effects on the environment and human health. An important tool in integrated olive fly management could be the use of products with a repellency and oviposition deterrence effect. This research yielded experimental evidence of significant oviposition deterrent activity on the olive fly as side effects of substances used in olive growing such as fungicides or plant biostimulants, highlighting the potential use of these products in B. oleae management.The control of Bactrocera oleae is fundamental to decreasing the significant production loss in olive cultivation. However, traditional containment based on the use of synthetic insecticides has been encountering serious limitations due to their negative effect on human health and the environment. Within the scope of integrated olive fly management, the use of products with repellency and oviposition deterrent activity might represent a more eco-friendly solution. In this study, we tested the oviposition deterrent activity of some commercial formulations already used in olive tree crops as fungicides (copper oxychloride, dodine, mancozeb, pyraclostrobin and difeconazole) and plant bio-stimulants (tannins, clay, flavonoids and a zinc-copper-citric acid biocomplex). The trials were conducted testing the oviposition behavior of mated olive fly females in both choice and no-choice assays. Our results showed that most of the substances have affected the ovipositional activity of the olive fly, except for difeconazole. Moreover, some products (copper oxychloride, flavonoids and tannins) have proven to differently influence the flies’ oviposition comparing the two tests. The repellent effect of these commercial products should be further studied to prove whether the repellency was due either to the active ingredient or to the co-formulants, and to assess their effect in the open field.

Oviposition deterrence, larvicidal activity and docking of β-germacrene-D-4-ol obtained from leaves of Piper corcovadensis (Piperaceae) against Aedes aegypti

The present study compared the chromatographic profile of oils from P. corcovadensis leaves obtained through hydrodistillation, maceration, supercritical fluid, headspace, steam distillation and ultrasound to determine the best method for the obtainment of β-germacrene-D-4-ol. The oviposition deterrent and larvicidal activities of this compound were carried out. The main compounds identified in the oils obtained using these methods were terpinolene, 1-butyl-3,4-methylenedioxybenzene, trans-caryophyllene and β-germacrene-D-4-ol, the proportions of which varied with the extraction method employed. Steam distillation (26.48 ± 0.37%), maceration (25.26 ± 0.39%) and supercritical fluid (24.38 ± 0.47%) were the best methods for extracting β-germacrene-D-4-ol. The oil obtained by maceration had the highest yield and was therefore chosen for the isolation of β-germacrene-D-4-ol. Larvicidal and oviposition assays of isolated compound and the oil obtained by maceration were performed with A. aegypti. Larvicidal activity (LC50) were 18.23 ± 1.19 ppm for β-germacrene-D-4-ol and 6.71 ± 0.16 ppm for the oil. The compound and oil also exhibited oviposition deterrence activity against the mosquito at concentrations of 5, 10 and 50 ppm. Moreover, it could be assumed that the sesquiterpene β-germacrene-D-4-ol achieves oviposition deterrence by interacting with odorant-binding protein 1 (OBP1) in Aedes aegypti, as the highest FitScore was found for this macromolecular target. This suggests how mosquito identifies β-germacrene-D-4-ol at the oviposition site. The findings demonstrate that β-germacrene-D-4-ol and the P. corcovadensis leaf oil obtained by maceration have considerable potential as larvicides and oviposition deterrents for the control of the A. aegypti.

Bioefficacy of plant oils applied through wooden cube impregnation against pulse beetle, Callosobruchus maculatus (F.) in green gram

Aim: To assess the bioefficacy of plant oils against pulse beetle, Callosobruchus maculatus (F.) in green gram through wooden cube impregnation. Methodology: Bioefficacy of plant oils viz; clove, sweet flag, eucalyptus, orange, cedar wood and neem at two doses, i.e., 0.5 ml and 1.0 ml dispensed through a small wooden cube was assessed against the pulse beetle in green gram. The oils except neem are essential oils. A wooden cube impregnated with plant oil was placed over the grain surface and ten pairs of adult insects were released into each treatment. Data on oviposition, adult emergence and grain damage was recorded in each treatment. Insect mortality due to fumigant effect of plant oil at 0.5 ml per cube was also observed. Results: There was no oviposition by pulse beetles in clove, sweet flag, and eucalyptus oil treatments at 0.5 ml against the untreated control which recorded 14 eggs/100 grains. Consequently, no population buildup was observed in clove, sweet flag, eucalyptus and orange oil treatments after 120 days. A total of 2313.33 adults emerged from the untreated green gram inflicting 46.67 percent grain damage. In fumigant toxicity test, hundred per cent mortality of pulse beetle adults was observed with orange oil in 48 hr of treatment and with eucalyptus oil in 72 hr at 0.5 ml. The results indicated that the plant oils showed strong oviposition deterrence as well as insecticidal activity against the pulse beetle. Thus, application of essential oils through a wooden cube was found highly effective to keep away the pulse beetles. Interpretation: Essential oils of clove, sweet flag, eucalyptus and orange when applied through wooden cube impregnation at a dose as low as 0.5 ml showed strong oviposition deterrence and insecticidal activity against pulse beetle. The insecticidal activity of oils can be attributed to the fumigant action and can be used effectively to prevent pulse beetle infestation in grain legumes.

Larvicidal activity against Aedes aegypti and molecular docking studies of compounds extracted from the endophytic fungus Aspergillus sp. isolated from Bertholletia excelsa Humn. & Bonpl.

Endophytic fungi are microorganisms capable of colonizing the interior of plant tissues without causing damage to them. The study of the secondary metabolites produced by their vast biodiversity fungal is relevant for the discovery of new products for biotechnological and agrochemical applications. In addition, extract of the endophytic fungus Aspergillus sp., isolated from the almonds of Bertholletia excelsa Humn & Bonlp collected in the Brazilian Amazon, oviposition deterrent, and larvicidal activity of against Aedes aegypti. In the oviposition deterrence test was observed that females able to lay eggs preferred the control oviposition sites (46.6%). Furthermore, the extract showed larvicidal activity with LC50 26.86µg/mL at 24h and 18.75µg/mL at 48h. Molecular docking studies showed the compound Aspergillol B a potent larvicide by to inhibit the acetylcholinesterase enzyme (- 7.74kcal/mol). These results indicate that compounds from secondary metabolites of Aspergillus sp., isolated from almonds of B. excelsa, are useful biological potential against vectors A. aegypti.

Oviposition behaviour and biochemical response of an insect pest, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae) to plant phenolic compound phloroglucinol

Phenolic compounds are the secondary metabolites (SMs) present in plants carrying different bioactivities. In the present study, we explored the influence of a phenolic compound namely phloroglucinol on oviposition behaviour and different biochemical entities of an insect pest Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae) using artificial diet. Phloroglucinol (IUPAC name: benzene-1,3,5-triol) affected the activity of antioxidant and detoxifying enzymes viz. superoxide dismutases (SOD), catalase (CAT), ascorbate peroxidases (APOX). dehydroascorbate reductase (DHAR), peroxidases (POX), phenol oxidase (PO), glutathione peroxidase (GPOX), glutathione S-transferase peroxidase (GSTpox), glutathione reductase (GR), glutathione S-transferase (GST) and esterases (EST) as well as the biological antioxidants viz. ascorbate content and glutathione. The lipid peroxide content (LP) and hydrogen peroxide content (H2O2) were significantly enhanced in the treated larvae indicating oxidative stress in the insect. Significant inhibition in oviposition was observed and effective repellency percentage increased with phloroglucinol treatment as compared to control. The oviposition deterrent activity and toxic effects of phloroglucinol on various biochemical parameters of Z. cucurbitae larvae revealed in the present study clearly confirms its suitability for use in pest management.

Insecticidal, Oviposition Deterrent and Antifeedant Property of Certain Plant Extracts against Pulse Beetle, Callosobruchus chinensis Linn. (Coleoptera: Bruchidae)

Background: The bruchid Callosobruchus chinensis (L.) is one of the major store grain pest of pulses capable of attacking wide range of legumes viz., green gram, black gram, chick pea and pigeon pea and causes 50 per cent damage during storage within 3 to 4 months. The infestation starts in the field, but heavy damage is done in storage. Hence, the current study was aimed to evaluate the insecticidal, oviposition deterrent and antifeedant activity of certain plant extracts against pulse beetle, C. chinensis under storage condition.Methods: The aquous extracts (10%) of Vitex negundo, Pongamia glabra, Cassia angustifolia and Calotropis gigantea were evaluated against the pulse beetle, Callosobruchus chinensis Linn. were carried out at the Department of Agricultural Entomology, Imayam Institute of Agriculture and Technology, Thuraiyur during 2019-20. The commercial product Azadirachtin was kept as a check and the mortality rate was assessed every 24 Hours after treatment (HAT) for three days.Result: The mortality rate after 72HAT was 85.8-87.5% with V. negundo, followed by C. angustifolia (73.33-80.00%) and P. glabra (70.0-75.0%). Azadirachtin gave 100% mortality of the beetle. The oviposition deterrence percentage for pulse beetle, C. chinensis was found to be highest in Calotropis gigantea (37.66-68.16%) followed by Pongamia glabra (30.91-41.50) and Vitex negundo (7.58-46.75) per cent, respectively. The antifeedant activity for pulse beetle was found to be very high when treated with Azadirachtin where there was no food consumption. This was followed by V. negundo (0.1g) and C. angustifolia (0.2g).

Production of Natural Insecticide on Management of Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) in Family Farming

Collard greens are commonly grown in family farming systems; however, damage caused by the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) reduces yields, leading to successive applications of insecticides and consequently, environmental and toxicological problems. Therefore, it is essential to search for alternatives that reduce the use of pesticides and are economically viable and accessible to small farmers. This study was aimed at evaluating the insecticidal activity of aqueous extracts of neem and tobacco on P. xylostella. First instar caterpillars were offered collard leaf discs treated with different concentrations (30 caterpillars per treatment) and after the third day, mortality was evaluated. To evaluate ovicidal properties, collard leaves with 30 eggs were immersed in extracts and after 48 h, viability was measured. Oviposition deterrent activity was assessed with 23 couples of P. xylostella released in cages (repetitions) containing treated collard plants and after 48 h, the number of eggs per plant was recorded. Neem and tobacco extracts exhibited larvicidal, ovicidal, and oviposition deterrent properties against P. xylostella, indicating that the use of these extracts may be promising alternatives in family farming systems.

Toxicity and Oviposition Deterrent Activities of Thyme Essential Oils against Anopheles arabiensis

Background. Malaria is one of the deadliest mosquito-borne diseases in sub-Saharan Africa and Ethiopia. Owing to their costs and environmental issues, synthetic insecticides are poor choices to control mosquitoes. Plant-based products can be considered as safe and biodegradable alternatives. The present study aimed to test the toxicity and oviposition deterrent activities of Thymus serrulatus and Thymus schimperi essential oils (EOs) against Anopheles arabiensis. Methods. Thyme EOs were extracted by hydrodistillation using the Clevenger-type apparatus. They were named Tar, Ala, and Yil after the areas of thyme collection Tarmaber, Alamata, and Yilmana Densa, respectively. Laboratory-based tests were used to determine the larvicidal, adulticidal, oviposition deterrent, and half lethal dose (LD50) of each EO. Results. The concentrations of 100 μl/L and 50 μl/L resulted in complete mortalities of larvae and adults, respectively, for all the three Eos considered. The EOs exhibited high repellency with oviposition activity index of −1 (OAI = −1) at concentrations of 50 μl/L (Tar), 100 μl/L (Ala), and 200 μl/L (Yil). Conclusions. The EOs of T. serrulatus and T. schimperi were effective against larvae and adult mosquitoes at small doses and resulted in oviposition deterrence at doses from 50 to 200 μl/L. Thus, these EOs are promising mosquitocides and oviposition deterrents. But, further tests both in the presence of already known and effective deterrents and field trials are required.

Essential oils and their bioactive compounds as eco-friendly novel green pesticides for management of storage insect pests: prospects and retrospects.

The control of storage insect pests is largely based on synthetic pesticides. However, due to fast growing resistance in the targeted insects, negative impact on humans and non-target organisms as well as the environment, there is an urgent need to search some safer alternatives of these xenobiotics. Many essential oils (EOs) and their bioactive compounds have received particular attention for application as botanical pesticides, since they exhibited high insecticidal efficacy, diverse mode of action, and favourable safety profiles on mammalian system as well as to the non-target organisms. Data collected from scientific articles show that these EOs and their bioactive compounds exhibited insecticidal activity via fumigant, contact, repellent, antifeedant, ovicidal, oviposition deterrent and larvicidal activity, and by inhibiting/altering important neurotransmitters such as acetylcholine esterase (AChE) and octopamine or neurotransmitter inhibitor γ-amino butyric acid (GABA), as well as by altering the enzymatic [superoxide dismutase (SOD), catalase (CAT), peroxidases (POx), glutathione-S-transferase (GST) and glutathione reductase (GR)] and non-enzymatic [glutathione (GSH)] antioxidant defence systems. However, in spite of promising pesticidal efficacy against storage pests, the practical application of EOs and their bioactive compounds in real food systems remain rather limited because of their high volatility, poor water solubility and susceptibility towards degradation. Nanoencapsulation/nanoemulsion of EOs is currently considered as a promising tool that improved water solubility, enhanced bio-efficacy, stability and controlled release, thereby expanding their applicability.

Larvicidal, oviposition-deterrence, and excito-repellency activities of four essential oils: an eco-friendly tool against malaria vectors Anopheles coluzzii and Anopheles gambiae (Diptera: Culicidae)

Mosquitoes are vectors of pathogens affecting humans causing morbidity, mortality and significant economic losses. Insecticides provide main-protection against vector-mosquitoes. However, synthetic insecticides, cause environmental contamination and increase vector resistance. These effects make it a priority to search for alternative means that are not deleterious to the environment and are public health acceptable. Here, we report oviposition deterrence, blood-feeding inhibition, excito-repellent effect, and larvicidal activities by essential oils (EOs) from the leaves of Lantana. camara L., Hyptis. suaveolens Poit., Hyptis. spicigera Lam, and Ocimum. canum Sims against local laboratory strains of Anopheles. gambiae s. s. and Anopheles coluzzii. All bioassays followed WHO standard protocols including minor modifications to evaluate the oviposition deterrence of gravid females, inhibition of adult blood-feeding and mortality caused by EO (essential oils), and larval susceptibility to EO. All EO tested showed strong oviposition deterrence, and the oviposition activity index ranged from −1 to - 0.75. Using a tunnel, we showed that EO have excito-repellent and blood-feeding inhibitory activities, and induced adult mortality. Engorged females tested ranged from 10.58 to 26.40%. L. camara EO had the highest larvicidal activity on both mosquito strains, and LC50 values of 102.78 and 92.20 ppm (part per million) for An. coluzzii and An. gambiae, respectively. The two mosquito strains showed similar susceptibilities to EOs. Overall, our results show that the EO used in this study could be used in developing effective and environmentally friendly approach to deter oviposition, repel mosquitoes, and control larvae.

Opuntia ficus-indica cladode extract is an embryotoxic, larvicidal, and oviposition-deterrent agent for the diamondback moth, Plutella xylostella

The search for new compounds to control Plutella xylostella, the main pest of Brassica crops, has been stimulated by the environmental impact of the insecticides currently used and reports of resistant populations. This work evaluated the effects of a cladode extract from Opuntia ficus-indica (CE) on the survival and development of P. xylostella, as well as on its oviposition behavior. Additionally, the effects on the histological organization of the larval midgut, as well as digestive enzyme activities, were evaluated. CE contained flavonoids, cinnamic derivatives, terpenes, steroids, and reducing sugars. High-performance liquid chromatography analysis confirmed the presence of rutin and compounds containing aliphatic chains and aromatic rings in their structures. CE reduced the viability of eggs with an EC50 (concentration that reduces egg viability by 50%) at 5.37% (w/v) and killed larvae with an LC50 (concentration that kills 50% of larvae) at 7.75% (w/v). Histological analysis revealed several alterations in the midgut of larvae exposed to the extract, including the presence of spherites, cell nuclei expulsion, the disappearance of the peritrophic membrane, and an increase in the number of goblet cells. CE inhibited the in vitro activity of proteases from larvae midgut extracts. The extract also presented oviposition-deterrent activity. In conclusion, cladodes of O. ficus-indica are a source of compounds toxic to eggs and larvae of P. xylostella and are able to interfere with oviposition site choice. The results suggest potential of CE as a botanical insecticide, though field trials are needed to confirm activity.

Silver nanoparticles containing stearic acid isolated from Catharanthus roseus: Ovicidal and oviposition-deterrent activities on Earias vittella and ecotoxicological studies

In the recent past, many agrochemicals have been used to control pests, but many of these fail due to the development of resistance. Many researchers, therefore, concentrate on developing new pesticide formulations from natural resources (plants/microorganism). In the present study, different extracts from Catharanthus roseus (Madagascar periwinkle) was evaluated for their ovicidal and oviposition deterrent activities against Earias vittella (spiny bollworm). Among the tested extracts DCM (Dichloromethane) extract showed highest ovicidal activity (70.47%) and oviposition deterrent activity (75.41%) against E. vittella. Based on this biological activity, DCM extract was fractionated and isolated 7 fractions; all of these were evaluated for their ovicidal and oviposition deterrent activity against E. vittella. Maximum ovicidal and oviposition deterrent activity was recorded in fraction 5, followed by the 7th fraction. Stearic acid was isolated from fraction 5 and was subjected to nanoparticle synthesis. This nanoparticle was tested for its effects against E. vittella. It was found to exhibit 100% oviposition deterrent and 95% ovicidal activities against E. vittella, and also reduced the protein (53.63%), glutothionine esterase (39.16%), and esterase activity (45.25%) of the treated larvae. The synthesized nanoparticle was subjected to ecotoxicology evaluation against Daphnia sp. (water fleas) and Cyprinus carpio (common carp). The nanoparticle showed >100 mg/L for EC50 and LC50 against both aquatic organisms. Based on the result, it could be studied further to develop the ecofriendly formulation with stability studies for agriculture pest management.

Bioactivity of Plant Essential Oil against Potato Tuber Moth,Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae).

Phthorimaea operculella (Potato tuber moth) is a destructive pest of stored potatoes and potato crops, primarily in subtropical areas of the globe. It is a pest of the field as well as storage, the larvae damage the crop through the foliage, stem, and tubers too. The manifestation of potato tuber moth primes to high economic damages in production worldwide. Post-harvest protection of the potato tubers becomes important and is challenging. A treatment with chemical agents is a possible strategy but cannot be recommended for food items hence alternative methods become important in control of these moths. The present study deals with the assessment of plant oils of Cinnamomum verum, Cupressuss sempervirens and Cymbopogon nardus. These plant oils were used to evaluate the larvicidal, adulticidal, Insect growth regulatory, repellency and oviposition deterrence activities against potato tuber moth. Results of the present work indicated that all the test oils show some promise as pest control agents against P. operculella. Oil of C. verum has exhibited promising toxic action (larvicidal LC50 = 110.10 μg/cm2, adulticidal LC50 = 49.78 μg/cm2). The oil of C. nardus caused promising IGR activity (delay in development = 16.2 days) All three plant oils have shown multifarious activity and can be a part of an eco-friendly and user-friendly method of control.

Artemisia vulgaris efficacies against various stages of Aedes aegypti.

Background and Aim:Aedes aegypti is the vector of dengue fever, dengue hemorrhagic fever, chikungunya, and, most recently, Zika. Dengue fever is one of Indonesia’s endemic diseases. The principal tool for preventing dengue is controlling Ae. aegypti by chemical insecticides since vaccine against dengue is still under research. However, Ae. aegypti developed resistance to various chemical insecticides worldwide. Therefore, research on alternate compounds as mosquito insecticides is urgently needed. This study demonstrated the efficacy of Artemisia vulgaris extract as larvicidal, ovicidal, adulticidal, repellency, and oviposition deterrent activity against Ae. aegypti.Materials and Methods:A. vulgaris was obtained from Temanggung, Indonesia, while the eggs of Ae. aegypti were collected from Yogyakarta, Indonesia, and were hatched in Laboratory of Parasitology, Faculty of Veterinary Medicine, Universitas Gadjah Mada. Larvicidal activity was evaluated according to the WHO protocol; adulticidal activity was performed using the Centers for Disease Control protocol. Oviposition activity was evaluated using ovitraps added with A. vulgaris extract, complete protection time in the repellent assay was defined as the number of minutes elapsed between compound application and the landing of the first mosquito.Results:A test of the larvicidal activity of A. vulgaris extract returned an LC50 of 65.8 ppm (r2=0.9014) in 1 h and 18.6 ppm (r2=0.575) in 24 h. A. vulgaris was effective as an adulticidal, demonstrating LC50 values of 11.35 mg (r2=0.875) in 90 min, 9.63 mg (r2=0.924) in 105 min, and 6.46 mg (r2=0.925) in 120 min. A. vulgaris at a concentration of 1000 ppm was able to reach 96% of oviposition deterrent effect. The ovicidal assay, a concentration of 1000 ppm resulted in 82.67% of eggs remaining unhatched. An extract concentration of 80 mg/ml achieved 63.3±3.5% biting repellency in adults.Conclusion:This study gives a clear indication that A. vulgaris extract acts on Ae. aegypti at various developmental stages and is a potential alternative bioinsecticide for controlling this disease vector.

Oviposition Deterrent Activity and Ovicidal Effect of Pometia pinnata Leaves Extract against Dengue Vector, Aedes aegypti (Diftera: Culicidae)

Aedes aegypti is the main vector of dengue fever that most commonly occurred in Indonesia. The application of botanical insecticides is being developed as an alternative vector control. Botanical components have been reported as the potential alternative to inhibit the process of oviposition and fecundity suppression. This study aims to determine the oviposition deterrent activity and ovicidal effects of ethanol extract of Pometia pinnata leaves against Aedes aegypti. Oviposition deterrent assay was conducted on twenty bloodfed females in a cage (40 cm x 40 cm x 40 cm). One treated oviposition trap and one control oviposition trap were placed in the opposite corner of the cage. Four replicates were performed for each concentration. The eggs were counted and analyzed after 72 hours of trial. Ethanol extract of Pometia pinnata leaves have antioviposition effect on female mosquitoes Aedes aegypti at 400 ppm (effective repellency / ER = 56.38%; oviposition active index/OAI = -0.39) and 500 ppm (ER = 66.4%; OAI = -0.49). In the ovicidal assay, twentyfive eggs are used for determination ovicidal effect and five replicates were performed for each concentration. The hatched larvae were collected and counted daily. The ethanolic extract of Pometia pinnata leaves at 0.05%, 0,1%, 0.15%, 0.2%, and 0.25% concentration have ovicidal activity of 11%, 28%, 87%, 94%, and 98% against Aedes aegypti eggs, respectively. This study revealed that the ethanol extract of Pometia pinnata leaves could be a potential alternative in controlling the dengue vector.

Antifeedant, contact toxicity and oviposition deterrent effects of phyllostine acetate and phyllostine isolated from the endophytic fungus Diaporthe miriciae against Plutella xylostella larvae.

Larvae of the diamond back moth (DBM), Plutella xylostella, are destructive cabbage pests causing economic losses worldwide. Continuous application of synthetic pesticides to control this pest has resulted in environmental pollution and resistant pest strains. Thus, there is a crucial need to seek natural alternatives with minimal detrimental effects. This study was designed to investigate the antifeedant activities of endophytic fungi of Cyperus iria and to determine the antifeedant, contact toxicity and oviposition deterrent activities of phyllostine acetate and phyllostine of the endophytic Diaporthe miriciae fungus. Two cyclohexeneoxidediones, phyllostine acetate (1) and phyllostine (2), isolated from an ethyl acetate extract of D. miriciae exhibited strong antifeedant, contact toxicity, and oviposition deterrent activities against P. xylostella. Phyllostine acetate (1) and phyllostine (2) showed feeding deterrent indexes of 100% at 50 μg cm-2 in the no-choice leaf disc assay and 50% feeding deterrence (DC50 ) values of 9 and 4.7μg cm-2 respectively. The median lethal concentration (LC50 ) values of phyllostine acetate (1) and phyllostine (2) were 4.38 and 6.54 μg/larva in the contact toxicity assay. The oviposition deterrent indexes of the two compounds were 100% for phyllostine acetate (1) and 28.6% for phyllostine (2) at 50 μg cm-2 . Phyllostine acetate and phyllostine show promise as compounds for the control of P. xylostella. This study encourages further investigation of endophytic fungi of the family Cyperacea, for the development of natural pest control agents in agriculture. © 2019 Society of Chemical Industry.

Utilization of electrocoagulation for the isolation of alkaloids from the aerial parts of Stemona aphylla and their mosquitocidal activities against Aedes aegypti

The electrocoagulation (EC) technique is an alternative method of isolating natural products with the advantage of minimizing the amounts of organic solvents required for this process, which are often harmful to the environment. In this research, the EC and the conventional solvent extraction methods were used in the isolation of Stemona alkaloids from the aerial parts of Stemona aphylla. A comparison was made between the amounts of the isolated alkaloids and the solvents used. The isolated alkaloids were evaluated for their larvicidal, ovicidal and oviposition-deterrent activities against the dengue vector, Aedes aegypti. The morphology and histopatology of the alkaloid treated larvae were also investigated. Two Stemona alkaloids, (2′S)-hydroxystemofoline and stemofoline, were isolated from both the EC and the conventional method. The amounts of (2′S)-hydroxystemofoline from the EC method was about the same as that obtained from the conventional method. However, the amounts of stemofoline obtained from the EC method were about two times larger than those obtained from the conventional method. Importantly, the EC method required six times less total organic solvents. The larvicidal activity assays of (2′S)-hydroxystemofoline and stemofoline showed that these were highly effective against Aedes aegypti larvae with LC50 values of 3.91 μg/ml and 4.35 μg/ml, respectively. Whereas, the crude EC extract (LC50 = 11.86 μg/ml) showed greater larvicidal activity than the crude extract obtained from the conventional extraction method (LC50 = 53.40 μg/ml). The morphological observations of the (2′S)-hydroxystemofoline and the stemofoline treated larvae revealed that the anal gills were the sites of aberrations. A histopathological study showed that larvae treated with these alkaloids had cytopathological alterations to the epithelial cells of the midgut. At a concentration 40 μg/ml (2′S)-hydroxystemofoline showed 100% ovicidal activity on 24 h old eggs while stemofoline showed 97.2%. Furthermore, the oviposition-deterrent effects of (2′S)-hydroxystemofoline and stemofoline, at a concentration of 80 μg/ml were 99.5% and 97.2%, respectively.

Oviposition deterrent and ovicidal activity of three edible oils (black seed, sesame and soybean oils) against puls beetle, Callosobruchus chinensis (Lin.) (Coleoptera: Bruchidae) on green gram, Vigna radiata

The effectiveness of three different edible oils - black seed (Nigella sativa), sesame (Sesamum indicum) and soybean (Glycene max) was evaluated for the control of pulse beetle, Callosobruchus chinensis on green mung pulse, Vigna radiata. The oviposition deterrent and ovicidal activity of these three oils were compared between fresh mung pulses and pulses treated at different doses (1, 3 and 6 μl). The results indicated that the rate of oviposition and the mean number of emerged adults of C. chinensis on mung pulses treated with black seed, sesame and soybean oil were lower than their respective control pulses. The lowest number of eggs were recorded in soybean oil treated seeds (13.8 ± 1.07, 12.6 ± 1.36, 10.0 ± 1.82) followed by sesame (51.8 ± 4.63, 25.8 ± 8.52, 14.2 ± 4.50) and black seed oil (67.2 ± 9.71, 27.4 ± 5.52, 21.0 ± 5.54) at dose 1 μl, 3 μl and 6 μl, respectively in order. Soybean oil at the rate of 6μl/50 seeds was significantly effective (10.0 ± 1.82) to inhibit egg deposition. In case of ovicidal activity, minimum number of adults were emerged from black seed oil treated pulses (25.2 ± 2.73, 24.2 ± 0.58, 22.4 ± 1.17 at dose 1, 3 and 6 μl, respectively). Black seed oil at the rate of 6μl/ 50 seeds was the most effective (22.4 ± 1.17) than other edible oils.
 Bangladesh J. Zool. 47(1): 59-65, 2019

BIOACTIVITY OF CITRUS AURANTIFOLIA, CITRUS LIMON AND PIPER NIGRUM ESSENTIAL OILS ON CALLOSOBRUCHUS MACULATUS (F.) (COLEOPTERA:BRUCHIDAE)

ABSTRACT In the current study Callosobruchus maculatus adults were exposed to essential oils of Citrus limon, Citrus aurantifolia and Piper nigrum and the contact mortality, repellency, fumigation effects and oviposition deterrent activities of each oil were determined over a 72h period. After 72h, 50% mortality of C. maculatus adults was observed for C. limon at a concentration of < 1.56 µL/mL, for C. aurantifolia at a concentration between 12.5–25.0 µL/mL and for P. nigrum the concentration causing 50% mortality was 1.56 µL/mL. All oils tested displayed some level of repellency to C. maculatus after 12h and 24h. C. aurantifolia essential oil at concentrations above 6.25µL/mLwere classified as a Class IV repellent, while P. nigrum was classified as a Class IV repellent at 25.0 and 50.0 µL/mL at 24h post application and a Class V repellent only at 50.0 µL/mL at 12h. The results of the 50% fumigant mortality (FC50) indicated that P. nigrum essential oil was the most toxic fumigant (FC50 = 0.140µL/L air) among the three oils tested. Black pepper oil also took the shortest time (FT50 = 7.71h) to cause 50% mortality to a population of C. maculatus.The anti-oviposition effects reveals that both C. limon and C. aurantifolia gave relatively low DQ values at all concentrations. At 25.0 and 50.0 µL/mL, C. aurantifolia had higher values (0.62 and 0.64 respectively). However, apart from the lowest concentration, P. nigrum essential oil consistently gave high DQ values indicating its potential in preventing egg laying on Cajanus cajan seeds. Thus, the use of these essential oils can be considered as alternatives to the use of synthetic insecticides for management of C. maculatus