Inhibition Of Adult Emergence Research Articles

Susceptibility of Tribolium castaneum (Coleoptera: Tenebrionidae) and Trogoderma inclusum (Coleoptera: Dermestidae) to cold temperatures

Studies were conducted by exposing different life stages of Tribolium castaneum (Herbst), the red flour beetle, and Trogoderma inclusum (LeConte), the larger cabinet beetle, for different time intervals to −18 °C. Assessments were made of direct mortality to eggs, larvae, and adults, and eventual adult emergence of immatures. Data were described by non-linear equations. The eggs and larvae were the most tolerant life stage of T. castaneum. Eight hours of exposure were required for 100% kill of 3–4-day-old eggs and 0–10- and 11–21-day-old larvae, but only 4, 0.5, and 0.5 h respectively were required to completely inhibit adult emergence. For T. inclusum, the most tolerant life stage was 15–28-day-old larvae; 64 and 16 h respectively were required for complete mortality and inhibition of adult emergence. Results indicate that T. inclusum was the more tolerant species, and specific treatment protocols may be required for different stored product beetle species when using −18 °C as a disinfestation strategy.

X-ray radiation and development inhibition of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

Abstract Effect of X-ray radiation on the development inhibition was evaluated for all stages of the life cycle of Helicoverpa armigera to determine a radiation dose for potential quarantine treatment against the insect. ED 99 values for inhibition of hatching, pupation, and adult emergence from irradiated eggs were 413, 210, and 154 Gy, respectively. ED 99 values for inhibition of pupation and adult emergence from irradiated larvae were 221 and 167 Gy, respectively. Pupa was the most tolerant to X-ray radiation. ED 99 value for inhibition of adult emergence from irradiated pupae was as high as 2310 Gy, whereas that for inhibition of F 1 egg hatching was only 66 Gy. ED 99 value for inhibition of hatching of F 1 eggs which were laid by irradiated adults was estimated to 194 Gy. X-ray irradiation against H. armigera is recommended as an alternative method to methyl bromide fumigation for phytosanitary treatments during quarantine. X-ray radiation dose of 200 Gy is proposed as a potential quarantine treatment dose for H. armigera eggs and larvae.

Acute Toxicity of Two Tropical Plant Extracts on the Fecundity and Fertility of Culex Quinquefasciatus Say

Acute toxicity tests were conducted to determine the biological effects of partially purified extract of two tropical plants Croton hirtus L'Her., Pogostemon quadrifolius (Benth.) F.Muell on the juveniles of Culex quinquefasciatus Say. Rearing of C. quinquefasciatus larvae in water at concentration less than the critical concentrations for inhibition of adult emergence in 50% of treated larvae (EC50) of the ethyl acetate fraction of Croton hirtus and Pogostemon quadrifolius leaf extracts from hatching to emergence significantly decreased the fecundity of the C. quinquefasciatus and the hatchability of their eggs. At highest concentration of 50% EC50 of the extracts the decrease in the fecundity over the control ranged between 72.4 and 85.4 %.

Effect of electron beam irradiation on developmental stages of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

Abstract Helicoverpa armigera Hubner (Lepidoptera: Noctuidae), is an economically important and polyphagous pest, which harms various kinds of food crops and important agricultural plants, such as cotton and paprika. Effects of electron beam irradiation at six dose levels between 50 and 350 Gy on the egg (24–48 h old), the larval (4–5th instar), and the pupal (7-d old for female, 5-d old for male) development, and on the adult (1-d old) reproduction were tested to identify a potential quarantine treatment dose. Increased doses of irradiation on eggs decreased egg hatchability, pupation and adult emergence and increased larval period. ED 99 values for inhibition of hatching, pupation and emergence were 460.6, 236.9 and 197.8 Gy, respectively. When larvae were irradiated with more than 280 Gy, no larvae could develop into pupae. ED 99 values for inhibition of pupation and adult emergence were 265.6 and 189.6 Gy, respectively. Even though the irradiation on pupa did not completely inhibit adult emergence, most of the pupae emerged to deformed adults. When adults were irradiated, fecundity was not affected. However, F 1 egg hatching was completely inhibited at the dose of 350 Gy. ED 99 value for inhibition of adult emergence was estimated at 366.5 Gy. Our results suggest that electron beam irradiation could be recommendable as an alternative to MB and as a phytosanitary treatment for quarantine. A treatment dose of less than or equal to 220 Gy is suggested as a potential quarantine treatment to H. armigera egg for prevention of pupation and to larva for prevention of adult emerge.

The Effect of Some Plant Extracts on Mosquito Aedes aegypti (L.)

In this study, the biological effects of various concentrations of Melia azedarach, Rhazya stricta, Jatropha curcas, Artemisia herba alba, Calotropis procera, Matricharia chamomella and Diflubenzuron were assayed on an Aedes aegypti (L.) test population under controlled laboratory conditions. Concentration levels of responses were evaluated. Characteristics such as IC50 and IC90 the susceptibility of immature stages to these plant extracts and insect growth regulator and their accumulation effects were studied. The percentage mortality of the fourth instar of Ae. aegypti larvae increased significantly with latex concentrations, indicating a direct relationship between the concentration and different effects. The larval mortalities ranged between low or moderate. According the mode of action of different plant extracts and Diflubenzuron did not appear to give high percentage of mortality against larval stages, although in most cases a clearly delayed inhibition of adult emergence was noted. The survival pupae percentage that produced from treated with different concentrations indicated that increased significantly of pupal survival due to decreasing the concentrations. There were significantly larval mortality and inhibition adult emergency percent in the treated groups compared to the control group. The characteristics investigated here indicate that this plant extracts and insect growth regulators are effective alternatives for controlling the dengue vector.

Developmental inhibition of gamma irradiation on the peach fruit moth Carposina sasakii (Lepidoptera: Carposinidae)

Ionizing irradiation is a useful technique for disinfestation under plant quarantine as well as post-harvest management. Effects of gamma irradiation treatment were tested on different developmental events of Carposina sasakii, which is a serious pest of various orchard crops. Apple fruits infested by C. sasakii were irradiated by gamma rays ranging from 0 to 300Gy. Inhibition rates were determined on behavioral events related to development, including larval exit from apples, cocoon formation, adult eclosion, and oviposition. Failure rates of all these developmental events increased with increasing doses of irradiation. Rates of larval exit from apples and cocoon formation decreased to 13.2% and 1.7%, respectively, at 300Gy. However, the adult eclosion rate decreased to 5.4% at 100Gy and was completely inhibited at doses greater than 150Gy. LD99 values for the inhibition of cocoon formation and adult emergence was estimated into 313.4 and 191.0Gy. Furthermore, adults developed from irradiated larvae completely failed to lay eggs. Thus, irradiation of infested apples at doses of 200Gy and higher completely inhibited the next generation of C. sasakii. Our results suggest that gamma irradiation treatment would be a promising technique for the control of C. sasakii.

Aedes aegypti (Diptera: Culicidae): evaluation of natural long-lasting materials containing pyriproxyfen to improve control strategies.

Natural materials such as beeswax or a paraffin/stearin mixture containing pyriproxyfen and used as a slow release formulation may convert any breeding place into a larvicidal ovitrap for Aedes aegypti (L.) control. Effectiveness and residual activity of beeswax and paraffin/stearin 1:1 discs containing from 10(-5) to 10(-1) % pyriproxyfen and sticked at the bottom of plastic jars were evaluated for adult emergence inhibition (EI) on late 3rd or early 4th instar A. aegypti larvae. At the initial time t = 0, the EI was 100% for vessels containing beeswax or paraffin/stearin 1:1 discs containing up to 10(-4)% pyriproxyfen. For the lowest pyriproxyfen concentration of 10(-5)%, paraffin/stearin mixture gave a higher EI% value than beeswax (100 and 50%, respectively). Jars were kept at room temperature, and water was totally replaced every 15 days. Bioassays for residual activity repeated monthly showed that at 30 days and for pyriproxyfen 10(-5) % and both matrices, the EI values were low and comparable to control values. For pyriproxyfen 10(-4) %, EI remained above 95% for at least 90 days and around 75% up to 180 days. The EI values are always higher for paraffin/stearin mixture than for beeswax. For all other higher concentrations, 100% EI was obtained at least during 300 days. In a semi-field trial, paraffin/stearin/sand O-rings (2:1:2), containing pyriproxyfen 1%, were sunken in 200-l water-storage tanks and held outdoors in a shadow place. After 72 h, a 250-ml aliquot was taken (t = 0) obtaining 100 % EI. Water level was completed to 200 l every 15 days and bioassays repeated monthly as before. Residual activity remains with 100% EI at least for 6 months.

Pyriproxyfen for mosquito control: female sterilization or horizontal transfer to oviposition substrates by Anopheles gambiae sensu stricto and Culex quinquefasciatus.

BackgroundThe use of gravid mosquitoes as vehicles to auto-disseminate larvicides was recently demonstrated for the transfer of pyriproxyfen (PPF) by container-breeding Aedes mosquitoes and presents an appealing idea to explore for other disease vectors. The success of this approach depends on the female’s behaviour, the time of exposure and the amount of PPF that can be carried by an individual. We explore the effect of PPF exposure at seven time points around blood feeding on individual Anopheles gambiae sensu stricto and Culex quinquefasciatus fecundity and ability to transfer in laboratory assays.MethodMosquitoes were exposed to 2.6 mg PPF per m2 at 48, 24 and 0.5 hours before and after a blood meal and on the day of egg-laying. The proportion of exposed females (N = 80-100) laying eggs, the number of eggs laid and hatched was studied. Transfer of PPF to oviposition cups was assessed by introducing 10 late instar insectary-reared An. gambiae s.s. larvae into all the cups and monitored for adult emergence inhibition.ResultsExposure to PPF between 24 hours before and after a blood meal had significant sterilizing effects: females of both species were 6 times less likely (Odds ratio (OR) 0.16, 95% confidence interval (CI) 0.10-0.26) to lay eggs than unexposed females. Of the few eggs laid, the odds of an egg hatching was reduced 17 times (OR 0.06, 95% CI 0.04-0.08) in Anopheles but only 1.2 times (OR 0.82, 95% CI 0.73-0.93) in Culex. Adult emergence inhibition from larvae introduced in the oviposition cups was observed only from cups in which eggs were laid. When females were exposed to PPF close to egg laying they transferred enough PPF to reduce emergence by 65-71% (95% CI 62-74%).ConclusionPPF exposure within a day before and after blood feeding affects egg-development in An. gambiae s.s. and Cx. quinquefasciatus and presents a promising opportunity for integrated control of vectors and nuisance mosquitoes. However, sterilized females are unlikely to visit an oviposition site and therefore do not transfer lethal concentrations of PPF to aquatic habitats. This suggests that for successful auto-dissemination the optimum contamination time is close to oviposition.

Larvicidal, smoke toxicity, repellency and adult emergence inhibition effects of leaf extracts of Swietenia mahagoni Linnaeus against Anopheles stephensi Liston (Diptera: Culicidae)

ObjectiveTo analyze the larvicidal, smoke toxicity, repellency and adult emergence inhibition activity of crude and solvent extracts of Swietenia mahagoni (S. mahagoni) leaves against larva of Anopheles stephensi (An. stephensi). MethodsTo examine the mosquito larval mortality, third instars larvae of An. stephensi were terated with different concentrations of crude and ethyl acetate extracts of mature leaves of S. mahagoni. For smoke toxicity, comparative study was done between mosquito coils prepared from S. mahagoni leaves and commercial mosquito coils. Mosquito repellency was studied with crude and petroleum ether extracts of mature leaves. Inhibition in adult emergence was examined with crude and ethyl acetate extracts of leaves. ResultsAbout 97% mortality of third instars larvae was found in 0.5% crude and 80 mg/L ethyl acetate extracts of mature leaves after 72 h of exposure. Smoke of S. mahagoni leaves showed appreciable toxicity. Crude and petroleum ether leaf extracts of leaves showed repellency up to 2 h after treatment. Regression coefficients (R2) of adult emergence inhibition are close to one. ConclusionsThis study reveals that the plant, S. mahagoni has considerable potentiality for malaria vector control. The plant could be utilized as source compounds for the development of safe plant-based herbal insecticides. The leaf extracts of S. mahagoni showed remarkable effect as larvicide, smoke toxic, repellent and adult emergence inhibitor against An. stephensi.

Clerodendron inerme Gaertn. plant as an effective natural product against dengue and filarial vector mosquitoes

ObjectiveTo investigate insecticidal properties of organic solvent extracts of Clerodendron inerme (C. inerme) leaves against larval stages of Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus (Cx. quinquefasciatus) mosquito species. MethodsThe sundried leaf powder of C. inerme was subjected for extraction using organic solvents viz. methanol, chloroform, petroleum ether and hexane extract, and were tested against third/fourth instar larvae of Ae. aegypti and Cx. quinquefasciatus species in accordance with WHO standard methods. Experiments were conducted in four replicates with control group containing water alone and positive control group containing respective solvent (dimethylsulfoxide/acetone) used for dissolving the extracts. ResultsAmong the four solvent extracts, hexane extract has effective growth disruptive activity against Ae. aegypti, and showed positive tests for presence of four groups of phytochemical constituents viz. tanin, phytosteriod, terpenoid and cardiac glycoside. The hexane extract was tested against field collected filarial vector Cx. quinquefasciatus larvae for growth disruptive activity. Adult emergence inhibition values for 50 percent suppression (EI50) of the tested population for methanol, chloroform, petroleum ether and hexane extracts treated against third instar larvae of Ae. aegypti were found to be 37.45, 14.79, 2.56 and 1.96 mg/L respectively, while hexane extract treated against Cx. quinquefasciatus was found to be equally effective with EI50 value of 3.74 mg/L. Hexane extract treated against fourth instar larvae of Ae. aegypti and Cx. quinquefasciatus showed EI50 values of 8.07 and 19.55 mg/L respectively in comparison with that of standard insect growth regulator methoprene demonstrating EI50 value of 0.05 mg/L. Besides, the hexane extract was also found to possess toxic effect against non-target organism Gambusia affinis (a bio-control agent), however, the lethal concentration (LC50=172.7 mg/L for 24 h) against Gambusia affinis was much higher in comparison with that of tested concentrations against Ae. aegypti and Cx. quinquefasciatus. ConclusionsWe conclude from the present investigation that the hexane extract of C. inerme has positive implications for its consideration in integrated control of dengue/filarial vectors due to their ecological distinctness in comparison with non-target organism and further due to ecofriendly nature of the extract in terms of easy biodegradability.

Botanicals as eco friendly biorational alternatives of synthetic pesticides against Callosobruchus spp. (Coleoptera: Bruchidae)-a review.

The article presents the potential of botanicals in the management of Callosobruchus spp., the primary insect pest causing deterioration to a variety of stored legume grains. Different botanical formulations have been reported time to time showing pronounced insecticidal activity, repellence to pest, oviposition deterrency, adult emergence inhibition, ovicidal, larvicidal, pupaecidal activity and feeding deterrency based on their contact toxicity and fumigation effects. Some of the botanicals have also been practically proved efficacious to protect the stored food commodities from the bruchids during storage conditions. Such botanical formulations have shown their promise in integrated management of the pest as semiochemicals by showing behaviour altering efficacy against the bruchids, thereby, reducing the induced pest resistance problem which is frequently reported with synthetic pesticides. Hence, they may be recommended in food security programmes as eco-friendly and biorational alternatives of synthetic pesticides providing integrated management of the losses of stored food commodities due to infestation of bruchids.

Effectiveness of Slow-Release Tablet Formulations of the IGR Diflubenzuron and the Bioinsecticide Spinosad Against Larvae ofAedes aegypti(L.)

The larvicidal effectiveness of slow-release tablet formulations of the chitin synthesis inhibitor Dudim® (diflubenzuron) and the bioinsecticide Natular™ (spinosad) against mosquito larvae of Aedes aegypti (L.) has been evaluated. The results showed that the test formulations provided long-term residual control against the larvae. Effective control giving 90–100 % inhibition of adult emergence was achieved for 10 weeks post-treatment for diflubenzuron and 7 weeks for spinosad. In addition, larval treatments with slow-release diflubenzuron formulations led to a marked prolongation in the time needed for blood meal digestion and a reduction in the reproductive potential of adult survivors. On the other hand, larval treatments with slow-release formulations of spinosad tablets affect neither the time of blood meal digestion nor the reproductive capacity of mosquito adults that emerged from surviving larvae.

A New Ovitrap Made of Slow Release Natural Materials Containing Pyriproxyfen for <I>Aedes aegypti</I> (Diptera:Culicidae) Control

ABSTRACT This initial study is aimed to measure the performance of incorporating pyriproxyfen in natural materials with low environmental impact to obtain slow release formulations that can be used as larvicidal or autocidal ovitraps avoiding hatched Aedes aegypti (L.) eggs to emerge as adults. Hollow candles made of beeswax or paraffin:stearin 1:1 mixture containing pyriproxyfen 0.01 and 0.05% were prepared and used as holding water containers for larval bioassay. Pyriproxyfen was released quickly into the larvae-breeding water. Ae. aegypti larvae were introduced immediately after the addition of tap water to the hollow candles (t = 1 min) or after 1, 4, and 8 h. More than 40% of the larvae did not emerge as adults for t = 1 min, reaching 80-100% when the larvae were added after 1 or 4 h, respectively. The hollow candles were kept at room temperature, and water was replaced every 15 d. Bioassays performed every 30 d showed that the residual activity obtained for both matrices and both concentrations of pyriproxyfen was higher than 360 d, with 100% inhibition of adult emergence.

Effect of triflumuron, a chitin synthesis inhibitor, on Aedes aegypti, Aedes albopictus and Culex quinquefasciatus under laboratory conditions

BackgroundResistance to traditional insecticides represents a threat to the control of disease vectors. The insect growth regulators (IGR) are a potential alternative to control mosquitoes, including resistant populations. The chitin synthesis inhibitors (CSI) are IGRs, which interfere with the insect molting process and represent one major class of compounds against Aedes aegypti populations resistant to the larvicide organophosphate temephos. In the present study, we evaluated the efficacy of the CSI triflumuron on Culex quinquefasciatus, Aedes albopictus and against several Ae. aegypti field populations.MethodsThe efficacy of triflumuron, against Cx. quinquefasciatus and Ae. albopictus was evaluated with laboratory strains through dose–response assays. Additionaly, this CSI was tested against seven Ae. aegypti field populations exhibiting distinct resistance levels to both temephos and the pyrethroid deltamethrin. Aedes aegypti populations were exposed to both a dose that inhibits 99% of the adult emergence of mosquitoes from the susceptible reference strain, Rockefeller, (EI99 = 3.95 μg/L) and the diagnostic dose (DD), corresponding to twice the EI99.ResultsOur results indicate that triflumuron was effective in emergence inhibition (EI) of Cx. quinquefasciatus (EI50= 5.28 μg/L; EI90= 12.47 μg/L) and Ae. albopictus (EI50= 1.59 μg/L; EI90= 2.63 μg/L). Triflumuron was also effective against seven Ae. aegypti Brazilian populations resistant to both temephos and deltamethrin. Exposure of all the Ae. aegypti populations to the triflumuron EI99 of the susceptible reference strain, Rockefeller, resulted in complete inhibition of adult emergence, suggesting no cross-resistance among traditional insecticides and this CSI. However, a positive correlation between temephos resistance and tolerance to triflumuron was observed.ConclusionThe results suggest that triflumuron represents a potential tool for the control of disease vectors in public health. Nevertheless, they point to the need of constant monitoring of the susceptibility status of vector populations to CSIs.

팥바구미에 대한 도꼬마리 열매의 살충력 평가

화학합성 농약을 대체하기 위한 친환경 방제법 개발을 위해 1, 2, 4%의 도꼬마리 열매 수용성 추출물을 이용하여 팥바구미 살충력을 실험하였다. 실험한 추출 농도에서 곤충 치사율, 기피성, 산란율과 성충 우화 및 팥의 피해 억제에 효과를 보여 주었다. 4%의 추출물은 처리 후 2일 후에 26%의 치사율과 처리 후 3시간에 53.3%의 기피율을 각각 보였다. 또한 4%의 추출물을 팥과 섞었을 때 가장 낮은 산란율(113.7/암컷)과, 성충 우화율이 가장 많이 억제(37.0%)되었고 종자 손상을 가장 적게(42.3%) 받았다. 이러한 결과는 도꼬마리 추출물이 저장곡물을 팥바구미로부터 보호하는 종합적 방제수단으로 사용될 수 있다. In this study, 1, 2 and 4% aqueous extracts of common cocklebur (Xanthium strumarium) fruit were tested against pulse beetle (Callosobruchus chinensis) for development of an environmental friendly control methods of this pest. The common cocklebur fruit extracts showed effects on mortality, repellency, fecundity and adult emergence of C. chinensis and inhibited pulse grains from damage. The 4% extract showed the highest mortality (26%) and repellency rate (53.3%) at 2 day after treatment and 3 hours after treatment, respectively. The studied insects revealed lowest fecundity (113.7 female-1), highest percentage of adult emergence inhibition (37.0%) and lowest percentage (42.3%) of seed damage when they were reared on pulse grains mixed with 4% extract. This finding indicated that common cocklebur fruit extract may be used in the integrated management of pulse beetle for protecting stored grains.

Field comparison of thermal and non‐thermal ultra‐low‐volume applications using water and diesel as solvents for managing dengue vector, Aedes aegypti

To compare the effectiveness on Aedes aegypti (Linneo) (Diptera: Culicidae) of a larvicide-adulticide ULV formulation applied by a thermal or a cold fogger using different solvents. We applied, in field conditions, a ULV formulation containing pyriproxyfen and permethrin, using a thermal and a cold fogger and water or diesel as solvent. We determined the effectiveness of these applications on Ae. aegypti adults and larvae by different bioassays and measuring Breteau, house and adult indices. When water was used as solvent, the treatments applied with the cold or the thermal foggers were equally effective on adult mortality (close to 90%) and adult emergence inhibition (% EI) (close to 70%). When the thermal fogger was used with water as solvent, the adult mortality outside the houses (85%) was higher, but not significantly different, than with diesel (65%). The contrary happens inside (22%vs. 58%), while there were no differences in %EI. Adult and larval indices behaved similarly in all areas, with a slight tendency for the treatments applied using water as solvent to be more effective. Water-based formulations are equally or more effective than the one applied with diesel as solvent. The use of water as solvent will not only improve the effectiveness of this formulation but also reduce the environmental impact and costs of spraying compared to the use of diesel.

Efficacy of permethrin, dinotefuran and pyriproxyfen on adult fleas, flea eggs collection, and flea egg development following transplantation of mature female fleas (Ctenocephalides felis felis) from cats to dogs

A novel spot-on formulation combining permethrin, pyriproxifen and dinotefuran (Vectra 3D™ spot-on solution for dogs) was evaluated in adult Beagle dogs in a study to determine adulticidal efficacy, egg laying inhibition and viability of Ctenocephalides felis felis eggs (development and emergence of fleas from the collected eggs). Prior to treatment sixteen dogs were checked for their ability to keep fleas 24hours after infestation and were allocated to treatment groups: 8 dogs served as untreated controls, and 8 dogs were treated once with the tested formulation. The spot on was administered respecting the laboratory recommendations at a dosage of 65–126mg/kg of permethrin; 8.9–17.4mg/kg of dinotefuran and 0.8–1.5mg/kg of pyriproxyfen. Each dog was infested with 100 adult cat fleas ready to lay eggs after 72hours spent feeding on cats. Dogs were infested 24hours after treatment and then weekly during 63 days. Eggs were collected and counted 24hours after each infestation and dogs were combed 48hours after each infestation. Fleas were counted and removed. Collected eggs were placed in incubator to study their development in larvae and into newly emerged adults. A single treatment provided 99.7% adulticidal efficacy on fleas within 48hours after treatment and controlled re-infestations for up to 30 days (efficacy >96.20%, p<0.05). The egg laying inhibition was over 92.3% for up to 29 days (p<0.05). The adult emergence inhibition remained 100% during 8 weeks after treatment and was 99.8% nine weeks after treatment (p<0.001).

The efficacy of a chitin synthesis inhibitor against field populations of organophosphate-resistant Aedes aegypti in Brazil

The mosquito Aedes aegypti is the main focus of dengue control campaigns. Because of widespread resistance against conventional chemical insecticides, chitin synthesis inhibitors (CSIs) are considered control alternatives. We evaluated the resistance status of four Brazilian Ae. aegypti populations to both the organophosphate temephos and the pyrethroid deltamethrin, which are used in Brazil to control larvae and adults, respectively. All vector populations exhibited high levels of temephos resistance and varying rates of alterations in their susceptibility to pyrethroids. The effect of the CSI novaluron on these populations was also investigated. Novaluron was effective against all populations under laboratory conditions. Field-simulated assays with partial water replacement were conducted to evaluate novaluron persistence. Bioassays were continued until an adult emergence inhibition of at least 70% was attained. We found a residual effect of eight weeks under indoor conditions and novaluron persisted for five-six weeks in assays conducted in an external area. Our data show that novaluron is effective against the Ae. aegypti populations tested, regardless of their resistance to conventional chemical insecticides.

Larvicidal and Adult Emergence Inhibition Effect of Crude Aqueous Leaf Extract of Jatropha curcas Against Anopheles arabiensis (Diptera: Culicidea)

This study aimed at evaluating the larvicidal and adult emergence inhibitory effects of crude aqueous leaf extract of Jatropha curcas against laboratory reared late third instar larvae of Anopheles arabiensis. For this purpose, standard larvicidal and recovery bioassays were used. At 500–1000 ppm, larvicidal activity of aqueous leaf extract of J. curcas was comparable to the larvicidal activity of 0.5 ppm Temephos (positive control). The LC50 and LC90 values of crude aqueous leaf extract of J.curcas were found to be 359 and 921. 61 ppm, respectively. More than 70% adult emergence inhibition (IE) was occurred in larvae recovered from treatments with test concentrations ranging from 125–1000 ppm. Generally, crude aqueous leaf extract of J.curcas showed dose dependent larvicidal and adult emergence inhibitory activities against the tested larvae. Future studies are recommended to identify active chromatographic fractions from the crude aqueous leaf extract of J. curcas because its larvicidal and adult emergence inhibitory activities may not be due to the synergistic effect of its bioactive fractions.

Experimental Confirmation of the Bruchidae Natural Parasitism Efficacy using an Innovative Device, Friendly to the Environment

ABSTRACTDue to the high cost factor the existing methods of managing pests in stored grains are not feasible for small-scale farmers. Management of pests by using locally and naturally available materials will be affordable by farmers and it will also be environment-friendly. In the present work, an innovative device (parasitoid facilitator bin), friendly to the environment with provision for the free movement of parasitoids into the bin was designed and employed to manage one of the major pests of pulses, the cowpea weevil, Callosobruchus maculatus (F.). The parasitoids that naturally entered the experimental setup were the egg parasitoid, Uscana lariophaga (S.) and the larval and pupal parasitoid, Dinarmus basalis (R.). The number of pests (all life stages) gradually decreased in grains stored in bins where there was provision for the movement of natural parasitoids. Adult emergence was very high in the control (320 to 416 per 500 egg-carrying grains), whereas it was much lower (33 to 46 per 500 egg-carrying grains) in the experiment, i.e. in the parasitoid facilitator bin. The adult emergence inhibition index in the experiment was 81.21%. In areas where natural parasitoids are abundant, this bin can be a boon to the farmer and this may have practical implications in the development of efficient large- scale storage systems.