Effectiveness and residual activity comparison of granular formulations of insect growth regulators pyriproxyfen and s-methoprene against Florida mosquitoes in laboratory and outdoor conditions (original) (raw)
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Medical and Veterinary Entomology, 2003
The insect growth regulator (IGR) pyriproxyfen is highly active against mosquitoes (Diptera: Culicidae). Through continuous emersion of large larvae (instars 3 4) the concentration causing 50% inhibition of adult emergence (E150) was determined as 0.200p.p.b. for Aedes a1boppictu.s (Skuse) and 3.5 to 7 times less for Ochlerotatus trisrriatus (Say): 1E," 0.0288 p.p.b. As a possible method of application to larval microscosms of these species that oviposit in water containers and phytotelmata, the horizontal transfer of pyriproxyfen to larval microcosms by adult mosquitoes was evaluated under laboratory conditions. Gravid females were forced to walk on surfaces treated with pyriproxyfen (tarsal contact exposure) and then allowed to oviposit in larval microcosms. Using replicate bioassay cages, each with an oviposition container, and a factorial experimental design, we assessed Ae. albopictus for the efrects of (i) pyriproxyfen concentration (0.2: 0.3 and 0.4mg/cm2) contacted by gravid fenlales, and (ii) the number of treated gravid females added to bioassay cages (one, three or five females/cage), on the mortality of larvae in oviposition containers. Only 0.2mg/cm2 treatment rate was tested on Oc. triserirrtfrs. A significant (P < 0.05) curvilinear response in inhibition of emergence (IE) was achieved on both species. Densities of one or three treated Oc. triseriatus females/cage yielded IE rates of only 21-2796, whereas five treated females/cage resulted in 70% inhibition. With Ae. albopictus, densities of three or five treated femaleslcage yielded 48-67% and 59%73% IE, respectively, whereas one treated femaleicage gave only 4 3 0 % inhibition. Use of IGR-treated oviposition containers to achieve horizontal transfer of pyriproxyfen to mosquito oviposition sites could be a field management technique based on mosquito biology and behaviour. In binary choice tests with Ae. albopictlrs, horizontal transfer of pyriproxyfen from a container with a treated ovistrip (0.3 or 0.4mg/cm2) to an untreated n~icrocosm resulted in 1 4 3 8 % inhibition. In larval bioassays, pyriproxyfen activity declined markedly within 10days. Forcibly exposing gravid female mosquitoes to pyriproxyfen-treated paper surface did not affect their fecundity. However, from the 1st to 2nd gonotrophic cycles the egg hatch rate declined by 30% (P < 0.05). Some variation of results could be due to interactions between females at the oviposition site, possibly causing disproportionate transfer of pyriproxyfen to larval microcosms. Comparative studies of the oviposition behaviour of each mosquito are warranted and would potentially provide information needed to improve the technique.
Asian Pacific Journal of Tropical Biomedicine, 2016
To test the relative efficacy of pyriproxyfen and methoprene on mortality, deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes albopictus. Methods: Serial dilutions (0.01-0.05 mg/L) of methoprene, pyriproxyfen 0.5 water dispersible granules (WDG) and pyriproxyfen 1.0 WDG were used to assess mortality and inhibition of 3rd instar larvae of Aedes albopictus and Culex quinquefasciatus. Each concentration and control was replicated four times in completely randomized design. Data on larval mortality, growth inhibition, deformities and adult's emergence was recorded weekly. On the basis of best comparative performance, the efficacy of pyriproxyfen 1.0 WDG at 0.1 g/m 3 was also tested in the field by collecting treated water samples monthly for 1-6 months after field application. Twenty five 3rd instar larvae of Aedes and Culex spp. of the same cohorts were used for bioassays and compared with larvae in control cups containing 1 L of untreated tap water. Results: Results revealed variations in fatality of different insect growth regulators (IGRs) to the 3rd instar larvae of Culex and Aedes mosquitoes. Among the IGRs, pyriproxyfen 1.0 WDG was found best that exhibited significantly high emergence inhibition against Culex and Aedes spp. Based on the results, the IGRs were classified in terms of the tested parameters in order of pyriproxyfen 1.0 WDG > pyriproxyfen 0.5 WDG > methoprene. In case of field studies, pyriproxyfen 1.0 WDG, pool data of the entire target treated sites showed minimum adult emergence from water sampled of habitats treated with 0.1 g/m 3 of pyriproxyfen 1.0 WDG. Conclusions: It is thus concluded that IGRs can be utilized as environment friendly control measures for Culex and Aedes spp. of mosquitoes on small and large scale. This will reduce the use of conventional insecticides by the public health authorities and help in reducing selection pressure of insecticides.
Ovicidal activity of three insect growth regulators against Aedes and Culex mosquitoes
Acta Tropica, 2013
Interspecific variations in the susceptibility of freshly and embryonated eggs of Aedes albopictus, Ae. aegypti, Ae. atropalpus and Culex pipiens were tested against three classes of insect growth regulators (IGRs) including ecdysone agonist (azadirachtin), chitin synthesis inhibitor (diflubenzuron) and juvenile hormone analog (pyriproxyfen) at 0.001, 0.01, 0.1 and 1.0 ppm concentrations. Egg hatching inhibition was dose dependent, the highest being at 1.0 ppm concentration for freshly laid eggs of Ae. albopictus (pyriproxyfen: 80.6%, azadirachtin: 42.9% and diflubenzuron: 35.8%). Aedes aegypti showed lower egg hatching inhibition when exposed to pyriproxyfen (47.3%), azadirachtin (15.7%) and diflubenzuron (25.5%). Freshly laid eggs of Cx. pipiens were most susceptible to diflubenzuron. Aedes atropalpus eggs were tolerant to all three classes of IGRs. Embryonated eggs of Ae. albopictus, Ae. aegypti, Ae. atropalpus and Cx. pipiens were resistant to pyriproxyfen, azadirachtin and diflubenzuron than freshly laid eggs. The median desiccation time (DT 50) of Ae. atropalpus eggs was maximum (5.1 h) as compared to Ae. aegypti (4.9 h), Ae. albopictus (3.9 h) or Cx. pipiens (1.7 h) eggs. Insignificant relationship between the rates of desiccation and egg hatching inhibition suggests other factors than physical providing eggs the ability to tolerate exposures to various IGRs. Egg hatching inhibition was due to the alteration in embryonic development caused by IGRs. Changes in the egg shell morphology and abnormal egg hatching from the side of the egg wall instead of operculum, was observed at higher concentrations of diflubenzuron. Morphological and physiological variations in eggs may be the key factor to influence the ovicidal efficacy of IGRs. The present data provide a base line for the improvement of the ovicidal efficacy of the insecticide and its formulation.
Journal of Medical Entomology, 2013
Pyriproxyfen, a juvenile hormone analog insect growth regulator (IGR), is a recommended insecticide for the control of container-inhabiting mosquitoes. The effects of eight container substrates (three plastics, wood, tire rubber, clay pot, concrete, and glass) were studied on reduction of bio-efÞcacy of pyriproxyfen for Aedes albopictus (Skuse) in the laboratory. Insect growth regulatorbioassay of third instars showed signiÞcant increase of LC 50 with some substrates compared with control probably because of pyriproxyfen adsorption to the substrate. The LC 50 for the control substrate (glass mug) was 0.029 g/liter. In comparison to the control, LC 50 increased 150.1 times with tire rubber (4.354 g/liter) and 8 Ð10 times with wood and high-density polyethylene plastic containers. Slight increases of LC 50 were detected for clay pots, polypropylene, and polystyrene plastics (1.9 Ð2.7 times). Pyriproxyfen efÞcacy with concrete substrate was higher than with glass containers, which might be caused by high pH. The pH of water with wood (5.6) and concrete (9.8) substrates differed from the other substrates tested (6.3Ð7.1). There was no pupal mortality at pH 5Ð11 without pyriproxyfen; however, interaction of pH (5Ð11) with pyriproxyfen (0.05 g/liter) showed additive effects at both low and high pH values. Different substrates have variable impacts on pyriproxyfen efÞcacy, which might be associated with the failure of larval control strategies for the container mosquitoes under certain Þeld conditions.
PLoS ONE, 2013
An insect growth regulator, pyriproxyfen, has been used for the control of a range of pest insects, including mosquitoes. Pyriproxyfen is effective in inhibiting adult emergence and sterilizing adult females. The Asian tiger mosquito, Aedes albopictus (Skuse), is an important vector of dengue and chikungunya, and is expanding its distribution throughout Europe and the Americas. In the present study, we evaluated the impact of pyriproxyfen-treated bed nets on population growth of Ae. albopictus under semi-field conditions, using 6 small microcosms. We created microcosms containing breeding sites to simulate the natural ecosystem of vector mosquito and installing miniature bed net treated with 350 mg/m 2 pyriproxyfen in Experiment I and 35 mg/m 2 in Experiment II. For each experiment, we also established microcosms installing untreated polyethylene net (untreated control). The installing nets were provided with artificially torn holes, to simulate damage and allow mosquitoes to penetrate. We released 100 pairs of Ae. albopictus into each microcosm, and allowed them to feed on a mouse under the bed nets at approximately 1-week intervals. In comparison with the untreated control microcosms, the number of eggs laid by the released adults in the pyriproxyfen-treated microcosms was significantly lower in both Experiment I and II. Moreover, egg hatchability was significantly suppressed and pupal mortality was increased. Our results indicate that tarsal contact with pyriproxyfen has been shown to suppress egg production and hatchability in adult females and the auto-dissemination of pyriproxyfen into larval breeding sites by adult mosquitoes, through contact with pyriproxyfen-treated polyethylene bed nets, may suppress the mosquito population density. Citation: Ohba S-y, Ohashi K, Pujiyati E, Higa Y, Kawada H, et al. (2013) The Effect of Pyriproxyfen as a ''Population Growth Regulator'' against Aedes albopictus under Semi-Field Conditions. PLoS ONE 8(7): e67045.
Journal of the Egyptian Society of Parasitology, 2010
The biological effects of two insect growth regulators (IGRs), pyriproxyfen and diflubenzuron against larvae of the mosquito Aedes aegypti (L.) have been evaluated. Mosquitoes were collected from Jeddah governorate, west of the Kingdom of Saudi Arabia and maintained in the laboratory. According to IC50 values obtained (concentrations which inhibit the emergence of 50% of adults), diflubenzuron (0.00036 ppm) proved to be more effective by 11.4 fold of pyriproxyfen (0.0041 ppm). In addition to the delayed lethal action, larval treatment with the two IGRs, pyriproxyfen and diflubenzuron led to pronounced reduction in the reproductive potential of mosquito adults that emerged from these treatments. Pyriproxyfen caused a 33.2% decrease in egg production compared to 25.5% for diflubenzuron. The reduction in egg hatchability was by 40.6 and 36.2% for pyriproxyfen and diflubenzuron, respectively, with up to 4 fold higher reduction rates than in the control tests. These results shed light on...
Alexandria Science Exchange Journal: An International Quarterly Journal of Science Agricultural Environments, 2010
This study was carried out to evaluate the biological effects of two IGRs (Match ® and Baycidal ®) on Culex pipiens mosquitoes when fed the adults on sugar solution mixed with 0.1, 0.5 and 1 ppm of each compound. Some delayed effects of these treatments were also determined. The results indicated that the use of each of the tested IGRs caused a reduction in the blood-feeding activity of mosquito female when compared with the controls. The reductions were 18.2, 22.7 and 31.8% by using Match and 25, 27.3 and 36.3% by using Baycidal ® , respectively, at the tested concentrations. The reduction in biting activity of mosquito females may lead to a decrease in the number of fully engorged females and accordingly affect their reproductive capacity of mosquitoes. The use of Match ® and Baycidal ® at the tested concentrations caused a marked prolongation in the time needed for blood meal digestion by C. pipiens females. The prolongation percentages were 44.4, 48,8 and 55.5% by using Match and 51.1, 55.5 and 62.2% by using Baycidal ® , respectively. Also, treatments caused a reduction in the reproductive capacity. The maximum decreasing in egg production was 30.3% at concentration of 1 ppm of Match ®. The result showed that the treatment by Baycidal ® at 0.1, 0.5 and 1ppm led to a remarkable reduction in the egg production by 61.9, 66.1 and 69.2%, respectively and also the hatchability was reduced in the treated females. Subsequent study was carried out to investigate the delayed effect of IGRs Match ® and Baycidal ® on the hatched larvae. The result showed that the larval development was gradually inhibited by 17.8, 49.8 and 92.7% by using Match ® at 0.1, 0.5 and 1 ppm, respectively. On the other hand the larval development was completely inhibited after the treatment of adults fed by 0.5 and 1 ppm Baycidal ®. The larvae developed till the 2 nd instar but completely failed in molting to the 3 rd instar. Subsequent study was conduced on the effect of Match ® and Baycidal ® on the longevity of the survived mosquito adults that, the records showed that no significant differences in the mean of adult longevity between treatments and control.
Evaluation of Pyriproxyfen Applied in Barrier Sprays for Mosquito Suppression
2017
OF THESIS EVALUATION OF PYRIPROXYFEN APPLIED IN BARRIER SPRAYS FOR MOSQUITO SUPPRESSION. Despite advances in mosquito management, mosquito-borne disease in the United States is still of relevant public health concern and vector control is a top priority in preventing transmission of pathogens. Insecticide barrier sprays have become a common tool for suppression of mosquitoes in single-homeowner backyards. The application of the synthetic pyrethroid, lambda-cyhalothrin, to perimeter vegetation with a backpack sprayer has been shown to significantly suppress mosquito levels for around 6 weeks. In an attempt to lengthen the effective duration of treatment, the IGR, pyriproxyfen, was added to a backpack mist blower with lambdacyhalothrin, as adult mosquitoes exposed to pyriproxyfen have been shown to disseminate it to oviposition sites and to experience lowered fecundity. This treatment was compared to lambda-cyhalothrin alone and to a water control. Mosquito populations were sampled us...
International Journal of Environmental Research and Public Health
Aedes aegypti were exposed to water treated with mosquitocidal chips containing the insecticide pyriproxyfen in a polymer formulation. Chips were tested under different conditions; different water volumes, in containers made of different material, and in water with different levels of organic matter. Treated chips caused 100% mortality of Ae. aegypti during their pupal stage independent of size or type of container, and the mount of organic matter contained in the water to which the mosquito larvae were exposed. When mosquitocidal chips were used in >25% of the oviposition containers within their cages, there was a significant control of the mosquito populations. Mosquitocidal chips worked in different environments, caused significant mosquito population decreases, and were effective in controlling Ae. aegypti.
Journal of Medical Entomology, 2013
The residual efÞcacy of pyriproxyfen against Aedes aegypti (L.) was examined by treating 2-liter buckets with a range of rates of Sumilarv 0.5G (100, 10, 1, and 0.1 mg product/liter or nominal dose of 500, 50, 5, and 0.5 ppb active ingredient) under semiÞeld conditions. Approximately every 2 wk, pupal emergence inhibition (EI) was measured by using Cairns colony Ae. aegypti. Pooled water samples from the Þve replicate buckets were analyzed for active pyriproxyfen by using ultra-high-pressure liquid chromatography with tandem mass spectrometry detection. A strong doseÐ response in EI was exhibited, with the 0.1 mg/liter giving Ϸ50% EI for only the initial week, whereas the 10 and 100 mg/liter doses produced EI Ͼ 90% for 8 and 40 wk, respectively. Measurable levels of active ingredient were detected in the 100, 10, and 1 mg/liter treatments, with measured starting concentrations of just 1Ð2Ð1.4% of the delivered (active ingredient) dose. Pyriproxyfen was detected in the 100 mg/liter treatment through the entire course of the trial (60 wk).