Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi(Diptera:Culicidae)

Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),Aedes aegypti(Ae.aegypti) and Anopheles stephensi(An. stephensi).Methods:The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions.The hatch rates were assessed 48 h after treatment.The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima exerted zero hatchability(100%mortality) at 375.300 and 225 ppm for Cx.quinquefasciatus,Ae.aegypti and An.Stephensi,respectively.The methanol extract of E. coronaria found to be more repellenct than C.pukherrima extract.A higher concentration of 5.0 mg/cm^2 provided 100%protection up to 150.180 and 210 min against Cx.quinquefasciatus,Ae. aegypti and An.stephensi,respectively.The results clearly showed that repellent activity was dose dependent.Conclusions:From the results it can be concluded the crude extracts of E.coronaria and C.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.

Mosquito larvicidal and ovicidal properties of Eclipta alba(L.) Hassk(Asteraceae) against chikungunya vector,Aedes aegypti(Linn.)(Diptera:Culicidae)

Objective:The present study deals with the investigation of larvicidal and ovicidal activities of benzene,hexane,ethyl acetate,methanol and chloroform leaf extract of Eclipta alba（E.alba） against dengue vector,Aedes aegypti（Ae.Aegypti）.Methods:Twenty five earlyⅢinstar larvae of Ae.aegypti was exposed to various concentrations（50-300 ppm） and was assayed in the laboratory by using the protocol of WHO 2005;the 24 h LC50 values of the E.alba leaf extract was determined by Probit analysis.For ovicidal activity,slightly modified method of Su and Mulla was performed.The ovicidal activity was determined against Ae.aegypti to various concentrations ranging from 100-350 ppm under the laboratory conditions.The egg hatch rates were assessed 48 h post treatment.Results:The LC50 values of benzene,hexane,ethyl acetate,methanol and chloroform extract of E.alba against early third instar larvae of Ae.aegypti were 151.38,165.10, 154.88,127.64 and 146.28 ppm,respectively.Maximum larvicidal activity was observed in the methanol extract followed by chloroform,benzene,ethyl acetate and hexane extract.No mortality was observed in control.Among five solvent tested the methanol extract was found to be most effective for ovicidal activity against Ae.aegypti.The methanol extracts exerted 100%mortality （zero hatchability） at 300 ppm.Conclusions:From the results it can be concluded the crude extract of E.alba was an excellent potential for controlling Ae.aegypti mosquito.

A comparative study of the ovicidal and larvicidal activities of aqueous and ethanolic extracts of pawpaw seeds Carica papaya(Caricaceae) on Heligmosomoides bakeri

Objective:To assess the ovicidal and larvicidal activities of aqueous and ethanolic extracts of pawpaw seeds Carica papaya（Caricaceae） on the eggs and first stage larvae（L1） of Heligmosomoides bakeri.Methods:Eggs of this parasite were obtained from experimentally infested mice（Mus musculus） and larvae were from eggs after incubation at 25℃for about 72 hours.The eggs and larvae were exposed to ten different concentrations（0.125,0.25,0.375,0.5, 0.75,1.0,1.25,1.75,2.25 and 2.75 mg/mL） of both aqueous and ethanolic extracts respectively for 72 hours.Distilled water and 0.05%ethanol used as placebo and negative control,respectively. Results:Placebo and negative control group all showed average 92%embryonnation,98%egg hatching and 2%larval mortality,and did not affect development and larval survival.The extracts inhibited embryonic development,egg hatching and larval survival.In general,the ovicidal and larvicidal activities increased with increasing concentration of different extracts.The aqueous extract was found to be more potent on eggs than on larvae.At 2.75 mg/mL,only 8%of eggs embryonnated and 50%hatched to L1 vs 57%embryonic development and 79%hatching occurred in the ethanolic extract.However,this later extract was more efficient in preventing larval development producing 96%mortality as against 68%with the aqueous extract.Conclusions: These results shows the ovicidal and larvicidal properties of aqueous and ethanolic pawpaw seeds extracts.

Larvicidal,ovicidal and pupicidal activities of Gliricidia sepium(Jacq.)(Leguminosae) against the malarial vector,Anopheles stephensi Liston(Culicidae:Diptera)

Objective:To investigate the potentiality of mosquitocidal activity of Gliricidia sepium（C.sepium） （Jacq.）（Leguminosae）.Methods:Twenty five early third instar larvae of Anopheles stephensi （An.stephensi） were exposed to various concentrations（50-250 ppm） and the 24 h LC50 values of the G.sepium extract was determined by probit analysis.The ovicidal activity was determined against An.stephensi to various concentrations ranging from 25-100 ppm under laboratory conditions.The eggs hatchabilily was assessed 48 h post treatment.The pupicidal activity was determined against An.stephensi to various concentrations ranging from 25-100 ppm.Mortality of each pupa was recorded after 24 h of exposure to the extract.Results:Results pertaining to the experiment clearly revealed that ethanol extract showed significant larvicidal,ovicidal and pupicidal activity against the An.stephensi.Larvicidal activity of ethanol extracts of G.sepium showed maximum mortality in 250 ppm concentration（96.0±2.4）%.Furthermore,the LC50 was found to be 121.79 and the LC50 value was recorded to be 231.98 ppm.Ovicidal activity of ethanol extract was assessed by assessing the egg hatchabilily.Highest concentration of both solvent extracts exhibited 100%ovicidal activity.Similarly,pupae exposed to different concentratioiLs of ethanol extract were found dead with 58.10%adult emergence when it was treated with 25 ppm concentration.Similarly,18.36（n=30;61.20%）;21.28（70.93） and 27.33（91.10） pupal mortality was recorded from the experimental pupae treated with 50,75 and 100 ppm concentration of extracts. Three fractions have been tested for their larvicidal activity of which the Fraction 3 showed the LC50 and LC90 values of 23.23 and 40.39 ppm.With regard to the ovicidal effect fraction 3 showed highest ovicidal activities than the other two fractions.Furthermore,there were no hatchabilily was recorded above 50 ppm（100%egg mortality） in the experimental group.Statistically significant pupicidal activity was recorded from 75 ppm concentration.Conclusions:From the results it can be concluded the crude extract of G.sepium is an excellent potential for controlling An.stephensi mosquito.It is apparent that,iraction 3 possess a novel and active principle which could be responsible for those biological activities.

Ovicidal activity of Atalantia monophylla(L)Correa against Spodoptera litura Fab.(Lepidoptera:Noctuidae)

Objective:To evaluate the efficacy of Atalantia monophylla(A.monophylla)leaf in different solvent crude extracts and fractions against eggs of Spodoptera litura(S.litura).Methods:Hexane,ethyl acetate and chloroform solvent extracts of A.monophylla leaf and 12 fractions from hexane extract were screened at 5.0%t,2.5%,1.0%and 0.5%for crude extracts and 1000,500,250 and 125 mg/kg for fractions against the eggs of S.litura for the ovicidal activity.LC_(50)and LC_(90)were calculated using probit analysis.Results:Hexane crude extract showed maximum ovicidal activity of 61.94%at 5.0%concentration with a correlation value of r^2=0.81,and least LC_(50)value of3.06%.Hexane extract was fractionated using silica gel column chromatography and 12 fractions were obtained.Fraction 9 was active which showed maximum ovicidal activity of 75.61%at 1000mg/kg with the LC_(50)value of 318.65 mg/kg and LC_(90)value of 1473.31 mg/kg.In linear regression analysis,significant and high correlation(r^2=0.81%)was seen between concentration and ovicidal activity of hexane crude extracts and its active frsctien.Conclusions:As per our knowledge,this is the first report for ovicidal activity of A.monophylla against S.litura,A.monophylla could be used for the management of S.litura and other insect pests.

<i>In Vitro</i>Ovicidal and Larvicidal Activities of Stem Bark of <i>Terminalia glaucescens</i>(Combretaceae) against <i>Haemonchus contortus</i>

Objectives: To evaluate the in vitro activity of aqueous and methanolic extracts of stem bark of Terminalia glaucescens on the eggs and larval stages of Haemonchus contortus of sheep. Methods: The eggs were exposed for 24 hours in five different concentrations (625, 1250, 2500, 3750 and 5000 μg/ml) of methanol, hot water (decoction) and cold water extracts at room temperature (25°C). Distilled water, 1.25% DMSO and Albendazole were used as negatives and positive control respectively in the bioassay. Results: A significant effect was obtained with all of the three extracts and differences were observed depending on the parasitic stage. Hot water extract (HWE), Methanol (MET) and Cold water extract (CWE) inhibited embryonic development by 98.1%, 96% and 86.5% respectively at 5000 μg/ml, meanwhile Albendazole had a 77.9% inhibition. For the mean inhibition rate of egg hatching, there was a general increase in the inhibition rate with increase in concentration of the extract from 625 to 5000 μg/ml. Methanol extract had the highest inhibition rate in all concentration from 625 to 5000 μg/ml. Concerning larval mortality, HWE had the highest effect in L1 larval mortality in all concentration above 1250 μg/ml. Distilled water had very little larval mortality on L1 and L2 larvae by 3.3 and 3.3% respectively. Conclusion: This in vitro study brought out the ovicidal and larvicidal properties of stem bark of Terminalia glaucescens.

QTLs for ovicidal response to whitebacked planthopper in rice

Japanese japonica rice commonlyprovides with an ovicidal resistanceagainst the whitebacked planthopper(WBPH). Similarly, ovicidal activi-ty was also found to play a significantrole in a stable field resistance toWBPH in some Chinese japonicarice. Rice varieties with ovicidal re-

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.

Larvicidal,ovicidal and repellent activities of marine sponge Cliona celata(Grant) extracts against Anopheles stephensi Liston(Diptera:Culicidae)

Obective:To evaluate the larvieidal.ovieidal and repellent properties of solvent extracts of marine sponge Cliona celala(C.celata)(Grant) against the malarial vector Anopheles stephensi(An.stephensi) Listen.Methods:Marine sponge C.celala was thoroughly washed with distilled water and shade dried for 48 h.Then the sponges were homogenized and extracted sequentially with hexane,ethyl acetate and methanol,Lanvicidal and ovicidal activities were tested at four different concentrations viz.,62.5.125.0.250.0 and 500.0 ppm.for repellent study extracts were taken in three different concentrations viz..5.0.2.5.1.0 mg/cm at.Results:Among the three solvent extracts of C.celata,methanol extract showed thc highest lanvieidal activity at 500 ppm against the fourth inslar larvae of An.stephensi.The LC_(50)and LC_(90) values of C.celata methanol extract were recorded as 80.61 and 220.81 ppm against An.stephensi larvae respectively.High ovieidal activity of 91.2%was recorded al 500 ppm concentration of methanol extract.The haxane extract was found to be the most effective protectant against the adult female mosquitoes of An.stephensi.The mean protection time recorded in hexane extract was up to 245 min at 5 mg/cm^2 dosage against An.Stephensi adults.Conclusions:The screening results suggest that the hexane and methanol extracts of C.celata arc promising in mosquito control.Considering these bioaclivitics.C.celata could the probed further to obtain some novel pesticidal molecules.

Mosquito larvicidal and ovicidal properties of Pithecellobium dulce(Roxb.)Benth.(Fabaceae)against Culex quinquefasciatus Say(Diptera:Culicidae)

Objective:To assess the larvicidal and ovicidal potential of the crude hexane,benzene,chloroform,ethyl acetate and methanol solvent extracts from the medicinal plant,Pithecellobium dulce(P.dulce)against filariasis vector mosquito,Culex quinquefasciatus(Cx.quinquefasciatus).Methods:Twenty five early third instar larvae of Cx.quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol of W HO(2005).The larval mortality was observed after 24 h of treatment.The ovicidal activity was determined against Cx.quinquefasciatus mosquito eggs to various concentrations ranging from 100-750 mg/L under the laboratory conditions.Results:The methanol extract of the leaves and seed of P.dulce was the most effective against the larvae with LCs0 and LCgo values 164.12 mg/L,214.29 mg/L,289.34 mg/L and 410.18 mg/L being observed after 24 h of exposure.The efficacy of methanol was followed by that of the ethyl acetate,chloroform,benzene and hexane extracts.The mean percent hatchability of the egg rafts were observed after 48 h of treatment.About 100%mortality was observed at 500 mg/L for leaf and 750 mg/L for seed methanol extracts of P.dulce.Conclusions:From the results,it can be concluded that the larvicidal and ovicidal effect of P.dulce against Cx.quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

Self-/conspecific discrimination and superparasitism strategy in the ovicidal parasitoid Echthrodelphax fairchildii （Hymenoptera： Dryinidae）

Superparasitism in solitary parasitoids results in fatal competition between the immature parasitoids, and consequently only one individual can emerge. In the semisoli- tary ovicidal parasitoid Echthrodelphaxfairchildii （Hymenoptera： Dryinidae）, 2 adults can emerge under superparasitism with a short interval （〈24 h） between the first and second ovipositions. We determined the female parasitoid＇s behavioral responses under self- and conspecific superparasitism bouts with first-to-second oviposition intervals of 〈2 h. The self- and conspecific superparasitizing frequencies increased up to an oviposition interval of 0.75 h, with the former remaining lower than the latter, particularly for oviposition intervals of _〈0.25 h, suggesting the existence of self-/conspecific discrimination. The superparasitizing frequency plateaued for oviposition intervals of _〉0.75 h, with no dif- ference between self- and conspecific superparasitism. The ovicidal-probing frequency did not differ under self- and conspecific superparasitism, and was usually 〈20%. The females exhibited no preference for the oviposition side （i.e., ovipositing on the side with or without the first progeny） and almost always laid female eggs for any oviposition in- terval under self- and conspecific superparasitism. The sex ratio was not affected by the type of superparasitism, oviposition sides, or the occurrence of ovicidal probing. These observed results about the oviposition side, ovicidal probing, and sex ratios differed from the predictions obtained assuming that the females behave optimally. Possible reasons for the discrepancies are discussed： likely candidates include the high cost of selecting oviposition sides and ovicidal probing, and, for the sex ratio, the low frequency of encountering suitable hosts before superparasitism bouts.

Evaluation of Andrographis paniculata Burm.f.(Family.Acanthaceae) extracts against Culex quinquefasciatus(Say.) and Aedes aegypti(Linn.)(Diptera:Culicidae)

Objective:To investigate the larvicidal and ovicidal efficacy of different extracts of Andrographis paniculata（A.paniculata） against Culex quinquefasciatus（Cx.quinquefasciatus） Say and Aedes aegypti（Ae.aegypti ） L（Diptera:Culicidae）.Methods:Larvicidal efficacy of the crude leaf extracts of A.paniculata with five different solvents like benzene,hexane,ethyl acetate, methanol and chloroform was tested against the early third instar larvae of Cx.quinquefasciatus and Ae.aegypti.The ovicidal activity was determined against two mosquito species to various concentrations ranging from 50-300 ppm under the laboratory conditions.Results:The benzene, hexane,ethyl acetate,methanol and chloroform leaf extract of A.paniculata was found to be more effective against Cx.quinquefasciatus than Ae.aegypti.The LC50 values were 112.19,137.48, 118.67,102.05,91.20 ppm and 119.58,146.34,124.24,110.12,99.54 ppm respectively.Among five tested solvent,methanol and ethyl acetate crude extract was found to be most effective for ovicidal activity against two mosquito species.The extract of methanol and ethyl acetate exerted 100%mortality at 200 ppm against Cx.quinquefasciatus and at 250 ppm against Ae.aegypti. Conclusions:From the results it can be concluded the crude extract of A.paniculata was a potential for controlling Cx.quinquefasciatus and Ae.aegypti mosquitoes.

Phenotypic Expression of Whitebacked Planthopper Resistance in the Newly Established japonica/indica Doubled Haploid Rice Population

A new doubled haploid (DH) rice population was established from a cross between WBPH-resistant japonica Chunjiang 06 (CJ-06) and susceptible indica TN1. Sucking inhibitory and ovicidal resistance of the DH rice lines were evaluated on the basis of non-preference response of WBPH immigrants and honeydew excretion by WBPH females, and appearance of watery lesions in the necrotic discoloration of leaf sheaths ovipositied by WBPH,respectively. Both the major gene resistance to WBPH, sucking inhibitory and ovicidal resistance, showed 1 (resistant): 1 (susceptible) segregation ratio in the DH population. Relative density of WBPH populations and damage scores in the DH population indicated combined functions of both the major resistance genes as well as QTLs affecting the host plant response to WBPH infestations. Thus, the newly developed CJ-06/TN1 DH population could be a useful material to analyze major genes and QTLs for WBPH resistance in japonica rice.

Acaricidal Activity of Boenninghausenia sessilicarpa Against Panonychus citri

Acaricidal activity of Boenninghausenia sessilicarpa against Panonychus cirri was tested in the laboratory. Four solvents were used to prepare crude extracts, petroleum ether, chloroform, ethyl acetate, and ethanol, among which ethanol was the most effective one. The results suggested that ethanol extracts of B. sessilicarpa had eminent acaricidal and ovicidal activities. Concentrated extracts were prepared using petroleum ether, chloroform, ethyl acetate, or distilled water as solvent. Mite mortality rates in the concentrated extracts by petroleum ether, chloroform, or distilled water were significantly lower than those by ethyl acetate. The LC50 values of eggs and female mites were 0.7639 and 1.1033 mg mL^-1, respectively. After liquid chromatography and thin layer chromatography, the concentrated extracts were separated into 14 groups of fractions and further tests for their acaricidal and ovicidal activities were conducted. Fraction 2 was found to possess higher acaricidal and ovicidal activities. The mortality of eggs and adult mites were 85.83 and 63.07%, respectively. Moreover, fraction 2 showed moderate oviposition inhibition effect （0.8795） against P. citri when the used dose was higher than 2.5 mg mL^-1

Anthelminthic Activity of <i>Moringa oleifera</i>Leaf Extracts Evaluated <i>in Vitro</i>on Four Developmental Stages of <i>Haemonchus contortus</i>from Goats

Haemonchus contortus is a blood-sucking abomasal helminth of small ruminants responsible for major economic losses to small farmers worldwide. Widespread resistance to synthetic anthelminthics has stimulated a need for alternative strategies of parasite control, among which is the use of medicinal plants with natural anthelminthic properties. This study assessed in vitro the efficacy of infused and macerated aqueous extract as well ethanolic extract of Moringa oleifera against fresh eggs, embryonated eggs, L1 and L2 larvae of H. contortus. For this purpose, five different concentrations (0.625, 1.25, 2.5, 3.75 and 5 mg/ml) were prepared from dry extracts via serial dilutions with distilled water. Fresh eggs obtained from artificially infected goat feces were exposed to these different concentrations for 48 hours, while embryonated eggs and larvae were exposed for 6 and 24 hours respectively. Distilled water and 1.5% DMSO were used as negative control. The results were expressed in terms of mean inhibition percentage of egg embryonation, mean inhibition percentage of egg hatch and mean percentage of larval mortality. An overview of results revealed that ethanolic leaf extract of M. oleifera was most efficient on eggs by inhibiting 60.3% ± 8.2% and 92.8% ± 6.2% eggs embryonation at 3.75 and 5 mg/ml respectively with a significant difference (P 0.05), which contributed to obtaining the lowest LC50 value of 0.985 mg/ml. This extract also inhibited 99% ± 2% egg hatching of H. contortus at 5 mg/ml with an LC50 value of 1.7 mg/ml. Concerning activity on larvae, the ethanolic extract was also most potent against them by inducing 98.8% ± 2.5% and 100% ± 0% mortality of L1 and L2 larvae at 5 mg/ml respectively. Infused aqueous extract was more efficient on eggs than on larvae with an IC50 value less than 2 mg/ml and an LC50 value more than 3.5 mg/ml. Macerated aqueous extract showed good activity against the four developmental stages with LC50 values ranging from 2.08 mg/ml for L2 larvae to 2.92 mg/ml for L1 larvae and 2.37 to 2.52 mg/ml for embryonated and fresh eggs respectively. The current study showed that all three extracts of M. oleifera tested possessed potential ovicidal and larvicidal activities against H. contortus. However, further in vivo studies are necessary to validate the anthelminthic property of this plant.

Resistance Performance to Whitebacked Planthopper in Different Phenotypes of Japonica/Indica Doubled Haploid Rice Lines

Field performance of whitebacked planthopper （WBPH）-resistance of four phenotypes was evaluated in Chunjiang 06 （C J-06） / TN1 DH rice lines, which were expressed by different combinations of sucking inhibitory and ovicidal traits inherited independently from C J-06. WBPH established the highest populations in susceptible DH lines that had neither sucking inhibitorynor ovicidal resistance. Both immigration and subsequent population levels were kept below the damage-causing density in the sucking inhibitory DH lines even under a WBPH outbreak. WBPH could not build up populations in the DH lines having both the sucking inhibitory and ovicidal resistance. Although WBPH immigrated preferentially to non-sucking inhibitory DH lines with ovicidal resistance, subsequent population buildup was significantly suppressed. It was concluded that the differential performance to WBPH-resistance in CJ-06 / TN1 DH lines was primarily due to the sucking inhibitory trait, and complementarity to the ovicidal trait.

Effect of diflubenzuron on the chitin biosynthesis pathway in Conopomorpha sinensis eggs

Conopomorpha sinensis is the dominant borer pest of Litchi chinensis(litchi)and Euphoria longan(longan)in China.Control of C.sinensis is difficult because of its cryptic life habit;thus,an effective ovicide could be beneficial.The larvicidal effects of diflubenzuron(DFB)have been documented in many insect pest species.Therefore,DFB might be a useful ovicide to control C.sinensis.However,the detailed mode of action of DFB interference with insect molting and egg hatching is unclear.Thus,we studied alterations in expression of all genes potentially affected by DFB treatment using a transcriptome approach in 2-d-old C.sinensis eggs.Clean reads were assembled to generate 203455 unigenes and 440558 transcripts.A total of 4625 differently expressed genes,which included 2670 up-regulated and 1955 down-regulated unigenes,were identified.Chitin binding and chitin metabolic processes were among the most significant enriched pathways according to Gene Ontology analyses.Most of the genes that encode enzymes involved in the chitin biosynthesis pathway were unaffected,whereas genes that presumably encode cuticle proteins were up-regulated.Furthermore,altered expression patterns of 10 genes involved in the chitin biosynthesis pathway of C.sinensis embryos were observed in response to DFB treatment at different time points by quantitative reverse transcription polymerase chain reaction.We also observed abnormal development;there was reduced chitin content and modulated chitin distribution of newly hatched larvae,and altered egg hatching.Our findings illustrate an ovicidal effect of DFB on C.sinensis,and reveal more molecular consequences of DFB treatment on insects.

Mosquitocidal activity of indigenenous plants of Western Ghats,Achras sapota Linn.(Sapotaceae)and Cassia auriculata L.(Fabaceae)against a common malarial vector,Anopheles stephensi Liston(Culicidae:Diptera)

Objective:To evaluate the mosquito larvicidal,ovicidal,pupicidal and repellent activities of hexane,diethyl ether,dichloromethane,acetone and methanol extracts of Indian medicinal plants,Achras sapota(A.sapota)and Cassia auriculata(C.auriculata)at different concentrations against Anopheles stephensi(An.stephensi),a malarial vector.Methods:Twenty five early third instar larvae of An.stephensi were exposed to various concentrations(30-210 mg/L)of plants extracts and were assayed in the laboratory by using the protocol of WHO 2005;then after 24 h LC_(50) values of the A.sapota and C.auriculata leaf extract was determined by probit analysis.The ovicidal activity was tested with the extracts ranging from 50-350 mg/L.The pupicidal activity was recorded after 24 h of exposure to the extract.The repellent efficacy was determined against mosquito species at two different concentrations 1.5 and 3.0 mg/cm^(2) under laboratory conditions.Results:Among the five different extracts tested against the An.stephensi,methanol extract of A.sapota proved to be an more effective solvent extract in almost all the parameters studied than C.auriculata.Conclusions:It is inferred that the leaf extract of A.sapota and C.auriculata could be used in vector control programme.

Mosquitocidal properties of Oxystelma esculentum(Asclepiadaceae)-Indian medicinal plant tested against Ades aegypti(Linn.)(Diptera:Culicidae)

Objective:To evaluate the mosquitocidal activities of various solvent extract of Oxystelma esculentum(O.esculentum)against the medically important dengue vector mosquito,Aedes aegypti(Ae.aegypti)L.Methods:A total of 25 early third instar larvae of Ae.aegypti were exposed to various concentrations(60-300 mg/L)and were assayed in the laboratory by using the protocol of World Health Organization,2005;the 24 h LC_(50) values of the O.esculentum leaf extract was determined by probit analysis.The ovicidal activity was determined against the freshly laid eggs of Ae.aegypti to various concentrations ranging from 50-300 mg/L under laboratory conditions.The pupicidal activity was determined against pupae of Ae.aegypti to various concentrations ranging from 70-280 mg/L after 24 h of exposure to the concern extract.The repellent efficacy was determined against adult female mosquito species at 1.0,2.0 and 3.0 mg/cm^(2) under laboratory conditions.Results:The LC_(50) value of methanol extract of O.esculentum against 3rd instar larvae of Ae.aegypti was 125.82 mg/L.The same extract showed 100%egg mortality at 250 mg/L and also pupicidal activity observed against the pupae of Ae.aegypti at 280 mg/L.Conclusions:The present results suggest that the O.esculentum leaf extracts provided an excellent,potential phytopesticide for controlling Ae.aegypti mosquito.

Pesticidal activity of Rivina humilis L.(Phytolaccaceae)against important agricultural polyphagous field pest,Spodoptera litura(Fab.)(Lepidoptera:Noctuidae)

Objective:To evaluate the pesticidal activity of antifeedant,oviposition deterrent,ovicidal and larvicidal activities of benzene,dichloromethane,diethylether,ethylacetate and methanol extracts of Rivina humilis at different concentrations against agricultural polyphagous pest Spodoptera litura(Lepidoptera:Noctuidae)(S.litura).Methods:Antifeedant activities of the selected plant extract were studied as described by Isman et al.(1990),with slight modifications.For oviposition deterrent activity,ten pairs of(adult moths)S.litura were subjected in five replicates.After 48 h,the numbers of eggs masses laid on treated and control leaves were recorded and the percentage of oviposition deterrence was calculated.The ovicidal activity was determined against the eggs of S.litura.Twenty five early fourth instar larvae of S.litura were exposed to various concentrations and was assayed by using the protocol of Abbott’s formula(1925);the 24 h LC_(50)values of the Rivina humilis leaf extract was determined by probit analysis.Results:All the extracts showed moderate antifeedant activitiy;however,significant antifeedant,ovicidal,oviposition deterrent and larvicidal activities were observed in methanol extract.Conclusions:This study showed that the selected plant can be a potent source of natural antifeedant,oviposition deterrent,ovicidal and larvicidal activities against field pest S.litura.