Oviposition Deterrent Activity Research Articles

Insecticidal, biological and biochemical response of Musca domestica (Diptera: Muscidae) to some indigenous weed plant extracts.

In the current study; insecticidal, growth regulation, oviposition deterrence and repellency of petroleum ether extracts of Azadirachta indica, Penganum harmala, Datura stramonium, Tribulus terrestris and Chenopodium murale against 2nd instar larvae of housefly was investigated. Five different concentrations (5%, 10%, 15%, 20% and 25%) were used through larval feeding and the mortality data was recorded after 24, 48 and 72 hrs. Highest mortality was induced by P. harmala (63.87%) followed by D. stramonium (62.78%), A. indica (53.84%), T. terrestris (41.86%) and C. murale (4.09%) after 72 h at 25% concentration, respectively. Increased mortality was observed with increased time duration and concentration. Longest larval duration (9.33 ± 0.33 days) and pupal duration (7.33 ± 0.33 days) days) was recorded in larvae treated with 25% concentration of P. harmala which also caused a decrease in the activity of AChE, ACP, AKP, α-Carboxyl, and β-Carboxyl enzymes. However, at 25% concentration, C. murale showed highest oviposition deterrence activity (81.88%) followed by D. stramonium (79.58%). In comet assay test, at highest concentration (25%) the mean comet tail lengths represented by Penganum harmala, Datura stramonium and Azadirachta indica (Reference plant) were 10.20 ± 0.49, 9.20 ± 0.37 and 7.80 ± 0.49 μm while percent DNA damage was 10.56 ± 0.77, 10.67 ± 1.62 and 8.11 ± 0.85% respectively compared to controls cells. Phytochemical analysis indicated the presence of flavonoids, steroids, saponins, cardiac glycosides, tannins, alkaloids, terpenoids and anthraquinones. Fourier Transform Infrared spectroscopy (FTIR) analysis revealed the presence of phenolic flavonoids, saponins, tannins as major functional groups. Further studies are needed to explore and thus, to incorporate weed plant extracts for the management of house flies.

Neem oil water dispersible tablet as effective larvicide, ovicide and oviposition deterrent against Anopheles culicifacies

ABSTRACT User- and eco-friendly approaches to manage immature stages of mosquitoes are urgently needed in order to minimize the undesirable impact of synthetic pesticides on nature and mankind. Plant-derived pesticides are considered as user- and environmental friendly. In this study, attempts have been made to develop water dispersible tablet (WT), containing neem (Azadirachta indica) oil as a mosquitocide. The tablet dispersion with concentration of 40 mg/L exhibited 98% mortality against third instars larvae of Anopheles culicifacies followed by residual effect upto sixth week. Ovicidal effect on freshly laid eggs were observed. Oviposition deterrent activity of tablet suspension was also assessed, which showed reduction in egg laying of gravid female by 89%. The tablet suspension was found to be non-toxic to the non-target fish, Poecilia reticulate.

Oviposition deterrent activity of different botanicals against Spodoptera litura (Lepidoptera: Noctuidae) in soybean

Tobacco caterpillar, Spodoptera litura (F.) is a polyphagous pest widely distributed in south east Asia which is an economically important pest as it can cause 25 to 100 per cent crop loss by defoliation. Heavy use of insecticides caused it to gain resistance over almost all groups of insecticides. Use of botanicals is a conventional approach for pest management as it is a two-tier approach by being eco-friendly and also manages the pest population. Therefore, the present study was carried out to determine the ovicidal and repellent activities of botanicals viz., Datura leaf extract 5%, Annona leaf extract 5%, Marigold leaf extract 5%, Neem oil 5%, Pongamia oil 5% and Eucalyptus oil 2% against S. litura in soybean. The study revealed that the Eucalyptus oil 2 % was least preferred for oviposition as the number of eggs laid in this treatment were 71.20, out of which 31.50 per cent eggs hatched and it also possessed the lowest oviposition index 0.20, followed by Neem oil 5% as the number of eggs laid in this treatment were 157.20, among which 46.28 per cent eggs hatched having an oviposition index of 0.23. Hence, the results indicate that eucalyptus oil and neem oil were least preferred, hence the botanicals are reliable source for eco-friendly management of S. litura in soybean.

Larvicidal, adulticidal, and oviposition-deterrent activity of Piper betle L. essential oil to Aedes aegypti.

Background and Aim:Aedes aegypti is a primary vector of many arthropod-borne diseases. One of the diseases, dengue fever, is an endemic disease in Indonesia causing high mortalities for decades. There are no preventive and specific treatments for dengue so far. Therefore, prevention of this disease largely depends on the mosquito control. Since resistance to chemical insecticides occurred worldwide, the study on alternate and new mosquito insecticides are mandatory. This study aimed to demonstrate the effect of essential oil from P. betle L. in the larval and adult stages, as well as its influence on oviposition activity of A. aegypti mosquito.Materials and Methods:P. betle efficacy was evaluated in various stages of A. aegypti development. For the larvicidal activity, larvae instar III stage was used. Adulticidal assay in this experiment was performed using newly emerged A. aegypti. For oviposition assay, mated A. aegypti was tested for their responses to P. betle-treated and non-treated ovitraps.Results:P. betle L. - adulticide activity was effective with a concentration of 2.5 μl/ml, caused 100% mortality within 15-30 min. Larvicide activity was observed after 1 h, 24 h, and 48 h post-treatment with LC50183, 92.7, and 59.8 ppm and LC90 637, 525, and 434.7 ppm, respectively. Oviposition activity index was −0.917 in 1000 ppm. In addition, the eggs number of A. aegypti oviposition with 100 ppm of essential oil P. betle L. was 5 times lower than the control.Conclusion:This study demonstrated clearly that essential oil derived from P. betle L. potentially acts as alternate bioinsecticide to control A. aegypti population. The application can be varied or combined in different stages of mosquito development.

Toxicity of several botanical essential oils and their combinations against females of Aedes albopictus (Skuse) and Anopheles minimus (Theobald): Oviposition deterrent, ovicidal and adulticidal efficacies

Objective: To investigate the efficacies of 12 essential oil (EO) formulations from three Zingiberaceae plants (Alpinia galanga, Curcuma zedoaria, and Zingiber cassumunar) individually and in combination with an augmenting Eucalyptus globulus (E. globulus) EO against females of Aedes albopictus (Ae. albopictus) and Anopheles minimus (An. minimus). Methods: These formulations were evaluated for their ovicidal, oviposition deterrent and adulticidal activities against Ae. albopictus and An. minimus by a topical method, a double-choice method and a WHO susceptibility test, respectively. Results: It was found that all formulations of Zingiberaceae plants EOs augmented with E. globulus EO were more effective in oviposition deterrent, ovicidal, and adulticidal activities against the two mosquito species than all of the formulations used without E. globulus EO. Their oviposition deterrent, ovicidal and adulticidal activities were equivalent to those of 10% w/v cypermethrin. In contrast, 70% v/v ethyl alcohol as a control alone was not effective at all. The highest synergistic effect in effective repellency against Ae. albopictus was achieved by 5% Alpinia galanga EO + 5% E. globulus EO and against An. minimus was 5% Zingiber cassumunar EO + 5% E. globulus EO. Moreover, the highest synergistic effects in ovicidal activities against Ae. albopictus and An. minimus were achieved by 10% Zingiber cassumunar EO + 10% E. globulus EO and 5% Curcuma zedoaria EO + 5% E. globulus EO, respectively. For the adulticidal activities, the highest synergistic effect against two mosquitoes was achieved by 5% Curcuma zedoaria EO + 5% E. globulus EO. Conclusions: These results suggest that Zingiberaceae plant EOs augmented with E. globulus EO have a high potential to be developed into oviposition deterrent, ovicidal, and adulticidal agents for controlling populations of Ae. albopictus and An. minimus.

Oviposition deterrent activities of some plant extracts against tomato leaf miner, Tuta Absoluta meyrick (Lepidoptera: Gelehiidae)

Tuta absoluta Meyrick Lep Gelechiidae is a very serious pest worldwide causing damage to tomatoes In this study the oviposition deterrence efficacy of extracts obtained from Tanacetum vulgare L Asteracea Tanacetum parthenium L Asteracea Aleo vera L Liliaceae Melaleuca alternifolia Maiden amp Betce Myrtaceae and Juglans regia L Juglandecae on Tuta absoluta Meyrick Lep Gelechiidae was investigated Eggs laid daily were placed in Petri dishes and observed until pupa After larvae become pupae were distinguished male or females using a stereomicroscope After that two male and one female were released within cage to couple during h Adults were put into cages containing with extract treated plant The experiment was replicated four times including control Daily monitoring was conducted for fourteen days and the total number of eggs was recorded According to the results obtained the extract of T parthenium showed the highest deterrence effect at the highest concentration The extracts of T vulgare and A vera were the deterrence effect and in the same concentration respectively It was reported that the deterrence effect of Gamatol fungatol and J regia were and at the highest concentration respectively The percent oviposition deterrence was at Neem Azal T S The percent oviposition deterrence increased with increase in concentration of plant materials

Potential of essential oils to prevent fly strike and their effects on the longevity of adult Lucilia sericata.

Lucilia sericata is a facultative ectoparasite causing fly strike or myiasis in warm-blooded vertebrates. It is controlled by traps or insecticides, but both have drawbacks and alternative ways of control are urgently needed. Essential oils (EOs) of vetiver (Chrysopogon zizanioides), cinnamon (Cinnamomum zeylanicum), and lavender (Lavandula angustifolia) and their blends (OBs); OB1 (2 ml of each EO plus 4 ml of sunflower oil as a carrier) and OB2 (2 ml of each EO) were tested. Oils were tested at 5% for deterrence assays, and a dose response assay 0.01-0.6%, was conducted to determine forced-contact toxicity. We evaluated the efficacy of oils as oviposition deterrents, repellents/attractants, and their effects on mortality and longevity of adult L. sericata. Our data indicated that 0.2% EOs killed all flies by 5 min post-treatment and that vetiver oil greatly deterred flies from the oviposition medium and reduced adult longevity. Sunflower oil repelled all flies from ovipositing and greatly reduced the lifespan of treated adults. The blend of the four oils (OB1) had the greatest repellent effect on the flies. EOs have insecticidal, repellent, and oviposition-deterrent activities against L. sericata that could be used for suppression of blow fly populations.

Biopesticidal potential of green chemicals against Callosobruchus analis (f.) (Coleoptera: Bruchidae):

Pulses have 20-27% proteins which is 2- 3 times higher than traditional cereals. These constitute the main source of proteins for developing countries, like India where per capita consumption of the animal protein is low, thus they are rightly considered the poor man’s meat. India is largest pulse consumer, importer and producer country of the world occupying an area of 228.47 lakh hectares with the production of 17380 million tones every year. With the United Nations declaration of 2016 as International Year of Pulses to replace the social evil of malnutrition by legume, the research pertaining to the biology and bio intensive management of bruchids pests has become increasingly important. Therefore, laboratory bioassay of essential oils which are regarded as “Green Chemicals” extracted from Zanthoxylum armatum DC., Rabdosia rugosa Wall. ex Benth, Artemisia maritima Linn. and Colebrookea oppositifolia Sm. by hydro distillation was carried out against Callosobruchus analis (F.) to evaluate biopesticidal potential in terms of oviposition and progeny deterrence and ovicidal activities. There was a significant difference in the number of eggs laid on treated and control sets and among the different treatments of essential oils. Z. armatum at 100 µl/ml allowed the bruchid to lay only 19.15±3.6 eggs as compared to 82.35±4.5 in control and proved to be most effective treatment with 76.74% oviposition deterrence. R. rugosa and A. maritima oil were found most effective in reducing the egg hatchability to 48.00±3.2 and 49.52±2.2% respectively at a lowest dose of 10 µl/ml. Egg hatching inhibition percentage increased with an increase in concentration of all the treatments. R. rugosa oil at 100 µl/ml proved to be most effective in reducing the adult emergence with 85.48% progeny deterrence followed by A. maritima showing 81.67% deterrence. All the tested essential oils revealed a wide range of bioactivities against the bruchid pest.

English

Tabebuia avellanedae is an important timber source belonging to the family of Bignoniaceae. The latter is known for its richness in terms of variety of bioactive chemical constituents, and it has been used in folk medicine for treatment of various diseases. The aim of this work was to investigate the chemical composition, oviposition deterrent and larvicidal activities of the wood extracts of T. avellanedae from the Cerrado of Brazil. Extracts of acetone, ethyl acetate and ethanol from T. avellanedae were obtained using various extraction methods. Quantitative analysis of phytochemical screening confirmed the presence of phenols and tannins in the wood extracts, however, anthraquinones, coumarins and alkaloids were absent. The toxicity of T. avellanedae extracts against 3rd instar larvae of Aedes aegypti using maceration and Soxhlet extraction methods was analyzed. The acetone and ethyl acetate extracts obtained by Soxhlet extraction were more toxic against 3rd instar A. aegypti larvae, with CL50of 100.1 and 151.0 μg/mL, respectively. The mortality values (LT50 and LT95) were 38.66 and 66.74 min for ethyl acetate extract, respectively, and 53.47 and 119.96 min for acetone extract, respectively. In all cases, the assay showed that all extracts presented mortality of 100% to 3rd instar larvae after 12 h. The oviposition assay showed that gravid A. aegypti females laid their eggs preferentially in the control ovitraps. The ethanol extract at 333.3 μg/mL strongly deterred oviposition by 89.89% while the ethyl acetate and acetone extracts presented 89.04 and 68.10% deterrence, respectively. The bioactive compounds in T. avellanedae make it a potential source for the control of A. aegypti vectors, without promoting deforestation of trees. Key words: Mosquitoes, larvae, toxicity, Ipê-roxo, Aedes aegypti, phytochemical, phenolic compounds. &nbsp

Acaricidal activity of different fractions of Moringa peregrina on two spotted spider mite Tetranychus urticae (Acari: Tetranychidae)

The acaricidal, oviposition deterrence and repellent activity of the subsequent nonpolar to polar extracts and fractions of Moringa peregrina (Forssk.) Fiori Agricolt. was studied against Tetranychus urticae Koch under laboratory conditions at 25 ± 1 °C, 65 ± 5% RH and 16:8 (L:D) h. Leaf disc method was employed to study the acaricidal activity of the fractions. The statistical analysis revealed that the ethyl acetate fraction had the highest contact toxicity and repellency. The LC50 of the ethyl acetate fraction was 4.259 mg ml−1, showing a significant decrease compared to other fractions. The remaining LC50 values of the samples were 6.464 mg ml−1 (methanol), 7.992 mg ml−1 (butanol), 9.742 mg ml−1 (chloroform) and 10.350 mg ml−1 (hexane). Up to six hours after treatment, no mites were found in the area treated with ethyl acetate fraction. Hexane (70.25%) and chloroform (22.59%) extracts had the highest and the lowest ovicidal activity at 8 mg ml−1. However, at 4 mg ml−1, chloroform extract had the most oviposition deterrence (21.67%). From the findings, it could be concluded that, the ethyl acetate fraction of M. peregrina is contained effective bioactive compounds against T. urticae. Therefore, further investigations are necessary for commercialization of this promising product for the agrochemicals industries of the natural pesticides.

Oviposition Deterrent Efficacy and Characteristics of a Botanical Natural Product, Ocimum gratissimum (L.) Oil-Alginate Beads, against Aedes aegypti (L.).

This study was aimed at investigating the oviposition deterrent activity of Ocimum gratissimum (L.) essential oil (O. gratissimum oil) and its product, Ocimum gratissimum (L.)- alginate beads (beads), against Aedes aegypti (Ae. aegypti) mosquitoes. Chemical analysis of O. gratissimum oil obtained by hydrodistillation, using gas chromatography-mass spectroscopy techniques, presented eugenol (67.38%) and Z-β-ocimene (14.95 %) as major constituents. Good characteristics of beads were obtained by the orifice-ionic gelation method with calcium chloride as hardening agent and Tween®20 as emulsifier. The beads exhibited a good spherical shape and good hardness and flexibility with an average size of 1.49 ± 1.36 mm. The oil content, the yield percentage, and the entrapping efficiency were also examined. The beads (formulation code, F2) could prolong the essential oil release until the 10th d. This beads provided a remarkably longer oviposition deterrence activity against gravid Ae. aegypti with high percentage for 27 d, whereas free O. gratissimum oil showed a short period of time (8 d) in this activity. The stability study showed the stability of oil content and its compositions in storage condition. These results are very affordable approaches to control the dengue fever.

Bioactivity of Clusia palmicida Rich. ex Planch. & Triana (Clusiaceae) Leaf and Fruit Extracts Against Cowpea Bruchid Callosobruchus maculatus (Fab.) (Coleoptera: Bruchidae)

This is the first report of a Clusia species assessment for Callosobruchus maculatus management and provides reference information for future research. n-Hexane, chloroform, ethyl acetate and methanol extracts from the fruits and leaves of Clusia palmicida were evaluated at 1000, 500, 250, 125 and 62.5 ppm for contact mortality and oviposition deterrent activities against C. maculatus adults infesting dried Cajanus cajan seeds. Ethyl acetate leaf extract was most toxic (LC50 = 1289.74 ppm) at a corresponding median lethal time (LT50) of 64.89 h, while the n-hexane leaf extract exhibited the lowest LT50 value of 32.35 h. Methanolic leaf extract was most effective at reducing egg laying with 50% oviposition occurring after 38.77 h at 1000 ppm. All C. palmicida leaf and fruit extracts displayed contact mortality and oviposition deterrence against C. maculatus. The results suggest that leaves are more effective as a natural insecticide against C. maculatus than fruits.

Insecticidal effects of Vernonanthura nebularum against two economically important pest insects.

Vernonanthura nebularum (Cabrera) H. Rob. (Asteraceae), an endemic species from the north of Argentina, is a rich source of elephantopus-type sesquiterpene lactones. These compounds have proved to be promising antiparasitic agents, but there is no report about their action against pest insects. In this work we studied for the first time the antifeedant and toxic effects of V. nebularum natural products against the fall army warm Spodoptera frugiperda Smith and the oviposition deterrent activity against the fruit fly Ceratitis capitata Wiedemann. As a result, we found that extracts, fractions composed of sesquiterpene lactones and pure sesquiterpene lactones altered larval feeding behavior in the food choice test. Nutritional parameters of S. frugiperda larvae were also affected. Fraction II (300 μg/g of diet.), containing compounds 1, 2 and 3, was the most toxic substance with 80% pupal mortality and wing malformations in adults. In oviposition deterrent experiments against Ceratitis capitata, we observed a moderate effect at 30 μg/cm2 of the test compound. The most active substances were the methanolic extract, dichloromethane subextract and lactone 2. According to our results, V. nebularum natural products could be used for maximizing the effectiveness and specificity in future insecticide design with specific or multiple target sites, while ensuring the economic and ecological sustainability, in addition to combat the increasing resistance rates developed by synthetic pesticides.

Larvicidal, pupicidal and oviposition deterrent activities of essential oils from Umbelliferae plants against house fly Musca domestica

Objective: To evaluate the toxicity against house fly Musca domestica L. (M. domestica)-larvicidal, pupicidal, and oviposition deterrent activities of essential oils (EOs) from five plants: Anethum graveolens L. (A. graveolens), Centratherum anthelminticum L. (C. anthelminticum), Foeniculum vulgare Mill. (F. vulgare), Pimpinella anisum L. (P. anisum), and Trachyspermum ammi L. (T. ammi) Sprague. Methods: Dipping, topical and dual-choice assays were performed by using each EO at three concentrations (1%, 5% and 10%) as well as cypermethrin (positive control) and ethyl alcohol (negative control) in order to determine their larvicidal, pupicidal and oviposition deterrent activities against M. domestica mortality rate and morphogenic abnormality of larvae and pupae were recorded after 3 and 10 days of incubation. Oviposition deterrent activity was recorded for 5 consecutive days from the beginning of the assay. Results: All EOs at the highest concentration (10%) were highly effective in oviposition deterrent with 100% effective repellency and an oviposition activity index of -1.00. Ten percent of F. vulgare oil exhibited the highest efficacy against the larvae with 89.6% mortality rate at 3 days and an LC50 value of 5.4%. Ten percent of A. graveolens and T. ammi oils showed the highest efficacy against the pupae with 100% mortality and an LC50 value ranging from 1.81%-2.24%. Conclusions: These results indicate that F. vulgare, A. graveolens and T. ammi EOs are effective larvicidal, pupicidal and oviposition deterrent agents against house fly M. domestica.

Efficacies of four plant essential oils as larvicide, pupicide and oviposition deterrent agents against dengue fever mosquito, Aedes aegypti Linn. (Diptera: Culicidae)

Objective: To evaluate larvicidal, pupicidal and oviposition deterrent activities of four plant essential oils from Alpinia galanga (L.) Willd rhizome, Anethum graveolens L. (An. graveolens) fruit, Foeniculum vulgare Mill. fruit, and Pimpinella anisum L. fruit against Aedes aegypti (Ae. aegypti). Methods: Four essential oils at 1%, 5% and 10% concentrations were assessed for insecticidal activity against larvae and pupae of Ae. aegypti, following the procedure of a dipping method assay. Oviposition deterrent activity of four essential oils was evaluated on gravid female of Ae. aegypti by a dual-choice oviposition bioassay. Results: The results revealed that An. graveolens oil provided the strongest larvicidal activity against Ae. aegypti among four tested plant essential oils with the highest mortality rate of 100% and LC50 value of -0.3%. From the pupicidal experiment, An. graveolens also showed the highest toxicity against Ae. aegypti pupae with the highest mortality rate of 100% at 72 h and LC50 value of 2.9%. In addition, 10% An. graveolens had an oviposition deterrent effect against Ae. aegypti with effective repellency of 100% and an oviposition activity index of –1.0. Conclusions: An. graveolens oil has a good potential as a larvicidal, pupicidal and oviposition deterrent agent for controlling Ae. aegypti.

Essential oils from selected wooden species and their major components as repellents and oviposition deterrents of Callosobruchus chinensis (L.)

Essential oils (EOs) from different parts of some selected wooden plants (Illicium verum, Bursera delpechiana, Croton anisatum, Cinnamomum cassia and Aniba rosaeodora) and the major components, trans-anethole, trans-cinnamaldehyde, linalool and linalyl acetate, as well as the major component of Gaultheria fragrantissima, methyl salicylate were tested for adult repellence and oviposition deterrent effects on adzuki bean beetle (ABB), Callosobruchus chinensis L. in a Y-tube olfactometer assay and no choice assay, respectively. EOs of I. verum and C. anisatum as well as their common major component, trans-anethole and the major component of G. fragrantissima, methyl salicylate were effective repellents and had high degree of oviposition deterrent activity without affecting the seed viability. Linalool, the major component of A. rosaeodora and B. delpechiana EOs exhibited male repellency in higher concentrations but was not effective oviposition deterrent. From this study, two EOs: I. verum and C. anisatum and two major components; trans-anethole and methyl salicylate could be selected for use against C. chinensis for safe storage of adzuki bean.

Adulticidal, larvicidal, pupicidal and oviposition deterrent activities of essential oil from Zanthoxylum limonella Alston (Rutaceae) against Aedes aegypti (L.) and Culex quinquefasciatus (Say)

ObjectiveTo evaluate adulticidal, larvicidal and oviposition deterrent response of the essential oil from dried Zanthoxylum limonella (Z. limonella) fruit against Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus (Cx. quinquefasciatus). MethodsZ. limonella oil was tested by biological assays at 1%, 5% and 10% concentrations in ethanol. Adulticidal efficacy was tested against the 2–3 day old adult females. Larvicidal activity was tested against immature stage of mosquitoes. Oviposition deterrence of the oil was evaluated on gravid females. ResultsThe adult mortality was observed after 24 h with the LC50 of 6.0% for Ae. aegypti, and 5.7% for Cx. quinquefasciatus. Larvicidal bioassay was carried out with the 10% Z. limonella oil against immature stages of Ae. aegypti and Cx. quinquefasciatus, which caused 100% mortality after 12 h and 24 h. In the larvicidal experiment, Z. limonella showed effective result at 1%, 5% and 10% concentrations with the values of LT50 Ae. aegypti = 9.78, 5.61, 0.24 h for larvae and LT50 = 64.08, 21.23 h for pupae; Cx. quinquefasciatus had LT50 = 28.46, 20.25, 1.01 h for larvae and LT50 = 67.52, 27.96, 4.11 h for pupae, respectively. Oviposition deterrence of the oil was evaluated on gravid females. In the study, 10% Z. limonella showed 100% repellency for Ae. aegypti and 99.53% for Cx. quinquefasciatus. Likewise, oviposition activity indexes of these oil concentrations were all negative values ranging from–0.89 to −1.00 for Ae. aegypti and–0.64 to–0.99 for Cx. quinquefasciatus. The oviposition activity indexes values revealed that Z. limonella oil has deterrent effect, and it caused a remarkable negative response resulting in very few eggs. ConclusionsThis result indicates that Z. limonella oil can be used as an effective adulticide, larvicide and oviposition deterrent against Ae. aegypti and Cx. quinquefasciatus.

Plant oils as oviposition deterrents against winterform females of pear psylla, Cacopsylla pyri (L.) (Hemiptera: Psyllidae)

Oviposition deterrents have potential to prevent arthropod pest infestations making the crop habitat less or no favorable for pests to lay eggs and even to settle. In this study, seed oils of maize, safflower, rapeseed and castor oil plant were evaluated in the field between years of 2015 and 2016 for their oviposition deterrent activity against winterform females of pear psylla, Cacopsylla pyri (L.) (Hemiptera: Psyllidae), the most important insect pest of pears in Turkey. All the oils were used at three different concentrations, 1, 1.5 and 2 L/100 L water including 0.01% Tween-20 for a good mixture and applied at the dormant period (just before the first eggs were deposited by overwintered females). Only one application was made each year. Oviposition deterrency was evaluated by counts of eggs deposited by overwintered females of the pest on treated dormant shoots during the sampling times 3, 7, 14, 21 and 28 days after application. The results showed that significant reductions in total numbers of eggs laid by winterform females were observed in all the oil-treated plots compared with the controls sprayed with tap water including Tween-20 (0.01%). Safflower and castor oils exhibited 100% oviposition deterrent activity at all the concentrations during the 3 weeks period in both years. Even after 4 weeks, the deterrency of these oils was higher than 70%. In the control plots, the first eggs were deposited by overwintered females within 3 days after application in both years. These findings suggest that these oils are promising oviposition deterrents against winterform females of C. pyri.

Oviposition deterrent activity of basil plants and their essentials oils against Tuta absoluta (Lepidoptera: Gelechiidae).

The leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yields by up to 100% in greenhouses and fields, in several countries globally. Because synthetic insecticides lead to resistance and have adverse effects on natural enemies and the health of producers, alternative control methods are needed. In this study, we assessed the oviposition-deterring effect of basil plants, Ocimum gratissimum L. and O. basilicum L. (Lamiaceae), using dual-choice behavioural assays performed in flight tunnels. We found that both plants significantly reduced T. absoluta oviposition behaviour on a tomato plant located nearby. To evaluate the potential effect of basil volatile organic compounds, we formulated essential oils of both plant species in paraffin oil, and observed a similar oviposition-deterring effect. Gas chromatography analyses detected 18 constituents in these essential oils which the major constituents included thymol (33.3%), p-cymene (20.4%), γ-terpinene (16.9%), myrcene (3.9%) in O. gratissimum and estragol (73.8%), linalool (8.6%), β-elemene (2.9%) and E-β-ocimene (2.6%) in O. basilicum. Twenty and 33 compounds were identified of the volatiles collected on O. gratissimum and O. basilicum plants, respectively. The main components include the following: p-cymene (33.5%), γ-terpinene (23.6%), α-terpinene (7.2%), α-thujene (6.7%) and E-α-bergamotene (38.9%) in O. gratissimum, and methyl eugenol (26.1%), E-β-ocimene (17.7%), and linalool (9.4%) in O. basilicum. Four compounds (α-pinene, β-pinene, Myrcene, Limonene) were common in essential oils and plants. Our results suggest the valuable potential of basil and associated essential oils as a component of integrated management strategies against the tomato leafminer.

Repellent, oviposition-deterrent and egg-hatching inhibitory effects of some plant essential oils against citrus mealybug, Planococcus citri Risso (Hemiptera: Pseudococcidae)

The citrus mealybug (Planococcus citri) is a serious pest of citrus groves in Turkey and has recently caused considerable damages to some cut flowers (especially, roses and orchids) in greenhouses in Antalya (southwestern Turkey). In this study, repellent and oviposition-deterrent activities of essential oils from anise (Pimpinella anisum), rosemary (Rosmarinus officinalis), peppermint (Mentha piperita), Turkish oregano (Origanum onites) and thyme (Thymus vulgaris) were investigated against female adults of P. citri under laboratory conditions. The results from the study showed that all the essential oils tested had a repellent activity in varying degrees, and the repellency was concentration and time dependent. Based on the highest dose (5 mL/L water) and the longest time period after the insect introduction (96 h), the oils from O. onites and T. vulgaris had the highest percent repellency in both choice and no-choice tests (O. onites: 88.9 and 65.4%; T. vulgaris: 88.8 and 69.6%, respectively), and followed by P. anisum (80.1 and 50%) and R. officinalis (57.1 and 45.2%) oils. In the oviposition deterrency assays using the highest concentration (5 mL/L water), O. onites essential oil showed the most potent oviposition deterrency (63.7%) resulting in the lowest mean number of eggs laid by the mealybug females (48.8 eggs per female) followed by P. anisum (56.9%). Furthermore, these two oils had the most potent egg-hatching inhibitory effects and inhibited egg hatching by 59.2 and 46.8%, respectively. Overall results suggest that the essential oils tested may help for us in controlling P. citri populations in various agroecosystems.