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Juan-Blasco M.,Instituto Valenciano Of Investigaciones Agrarias Ivia | Sabater-Munoz B.,Instituto Valenciano Of Investigaciones Agrarias Ivia | Argiles R.,Transformaciones Agrarias SA TRAGSA | Jacas J.A.,Jaume I University | And 2 more authors.
Journal of Economic Entomology | Year: 2013

Vienna-8 sterile males are currently released in Spain to reduce wild populations of the medfly. Because pesticides are required to maintain populations of some citrus key pests below economic thresholds, there is a need to evaluate the effects of pesticides commonly used in citrus on Vienna-8 males. Males were exposed to differently aged residues of eight pesticides. Abamectin, etofenprox, etoxazole, petroleum spray oil, pymetrozine, and pyriproxyfen resulted harmless to Vienna-8 males. However, fresh residues of chlorpyrifos and spinosad caused high mortalities and had residual effects until 21 and 28 d after treatment, respectively. Following the same method, the lethal effects of chlorpyrifos and spinosad on Ceratitis capitata (Wiedemann) wild-type (wt) males were determined. Surprisingly, these pesticides resulted more toxic for wt than for Vienna-8 males. To determine whether these results could be attributed to intrinsic characteristics of the pesticides or to behavioral differences among Vienna-8 and wt males, a topical application trial was conducted. Vienna-8 males were twice as susceptible to chlorpyrifos as wt males, whereas their susceptibility to spinosad was slightly lower. These results in intrinsic toxicity did not directly explain the differences observed in the extended-laboratory tests with these pesticides. We hypothesize that the lower flight activity of Vienna-8 males relative to wt conspecifics can explain the lower risk observed for Vienna-8 males in the residual tests. Our results should be taken into account when planning area-wide Sterile Insect Technique programs against C. capitata especially in those areas where treatments with chlorpyrifos are approved. © 2013 Entomological Society of America.

Juan-Blasco M.,Instituto Valenciano Of Investigaciones Agrarias Ivia | Sabater-Munoz B.,Instituto Valenciano Of Investigaciones Agrarias Ivia | Argiles R.,Transformaciones Agrarias SA TRAGSA | Jacas J.A.,Jaume I University | And 2 more authors.
Pest Management Science | Year: 2013

Background: The success of an area-wide sterile insect technique (SIT) programme against Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) relies on the mating success of sterile males in the field. Limited information is available about the effectiveness of sterile males in achieving mates with wild females and how these matings contribute to reducing wild populations. To this end, firstly a mating competition test was performed in the laboratory with different release ratios (1:1:0, 1:1:1, 1:1:5, 1:1:10 and 1:1:20 for wild females:wild males:sterile VIENNA-8 males respectively) and different host fruit. Secondly, the same release ratios were evaluated under semi-natural conditions on caged trees and on sentinel host. Results: By means of molecular markers, VIENNA-8 male sperm was positively detected in those females exposed to the male ratios 1:5, 1:10 and 1:20 in the laboratory. In the field test, sterile VIENNA-8 male matings and the C. capitata progeny on apples were positively correlated with the ratio of sterile males released and with the percentage of sterile matings respectively. Conclusions: These results confirm the validity of using the molecular detection of VIENNA-8 male sperm to predict the C. capitata population under semi-natural conditions. Implications of these results in measuring the efficacy of an SIT programme are discussed. © 2012 Society of Chemical Industry.

Juan-Blasco M.,Instituto Valenciano Of Investigaciones Agrarias Ivia | Sabater-Munoz B.,Instituto Valenciano Of Investigaciones Agrarias Ivia | Pla I.,Transformaciones Agrarias SA TRAGSA | Argiles R.,Transformaciones Agrarias SA TRAGSA | And 4 more authors.
Bulletin of Entomological Research | Year: 2014

Area-wide sterile insect technique (SIT) programs assume that offspring reduction of the target population correlates with the mating success of the sterile males released. However, there is a lack of monitoring tools to prove the success of these programs in real-time. Field-cage tests were conducted under the environmental conditions of the Mediterranean coast of Spain to estimate: (a) the mating success of sterile Vienna-8 (V8) Ceratitis capitata males using molecular markers and (b) their efficacy to reduce C. capitata populations under six release ratios of wild females to wild males to V8 males (1:0:0, 1:1:0, 1:1:1, 1:1:5, 1:1:10, and 1:1:20). Statistical models were developed to predict: (a) the number of females captured in traps, (b) sperm ID (sterile or not) in spermathecae of the trapped females, and (c) the viable offspring produced, using release ratio and temperature as predictors. The number of females captured was affected by relative humidity. However, its influence in the model was low. Female captures were significantly higher in ratios 1:0:0 compared to ratios where V8 males were released. The proportion of V8 sperm in spermathecae increased with temperature and with the number of V8 males released, but leveled off between ratios 1:1:10 and 1:1:20. In all seasons, except winter (no offspring), viable offspring increased with temperature and was lowest for ratio 1:1:20. For the first time, a strong negative relationship between proportion of V8 sperm detected by molecular tools and C. capitata offspring was established. The models obtained should contribute to enhance the efficacy of SIT programs against this pest. Copyright © Cambridge University Press 2014Â.

Juan-Blasco M.,Jaume I University | San Andres V.,Jaume I University | Martinez-Utrillas M.A.,Transformaciones Agrarias SA TRAGSA | Argiles R.,Transformaciones Agrarias SA TRAGSA | And 3 more authors.
Journal of Applied Entomology | Year: 2013

Autocidal control of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) is an environmentally friendly and safe practice employed successfully worldwide. A key component in the Sterile Insect Technique (SIT) is to release sterile males that can compete with wild males in nature. Exposure of sterile males to ginger root oil (GRO) in the form of aromatherapy prior to release has been shown to significantly improve male competitiveness and performance. However, alternatives to GRO exposure are desired to (i) reduce personnel costs and handling-time requirements and (ii) find new aromatherapeutic compounds. In this study, alternatives to GRO aromatherapy were investigated, such as incorporating GRO into the post-teneral diet, or employing other molecules (limonene and linalool) occurring naturally in citrus release areas. Our results reveal that both the GRO-supplemented diet and linalool aromatherapy were equal to the GRO aromatherapy control in improving mating performance in sterile males. In contrast, exposure to limonene did not afford a mating advantage to sterile mates when compared to the control. In addition, sterile male survival was not affected by any of the treatments tested. Implications for how both new approaches could be implemented in SIT programmes in citrus production areas are discussed. © 2011 Blackwell Verlag, GmbH.

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