J. Sanchis

Evaluation of Traps and Lures for Mass Trapping of Mediterranean Fruit Fly in Citrus Groves

Abstract Mass trapping has proven to be a powerful weapon in the control of Ceratitis capitata (Wiedemann), and its application in Mediterranean countries has currently increased notably as a control method. In this study, the efficacy of newly developed traps and dispensers of attractants were assessed with the aim of finding the best trap and set the lifetime of the dispensers, thus improving the total efficacy of mass trapping. Efficacy trials with six different types of traps and six different types of female dispensers were carried out. Moreover, the lifetime of three female dispensers, including a new attractant composition dispenser with n-methyl pyrrolidine, were studied. Results show significant differences among the trap types using female attractants, with an advantage of nearly 3 times more catches in best trap. Tested female dispensers showed no significant differences in efficacy between trimethylamine and putrescine attractants regard n-methyl pyrrolidine, however we observed differences in lifetime between dispensers. Thus, there are significant differences among different types of traps and dispensers in efficacy, and the appropriate selection of the trap and dispenser will improve the mass trapping results.

Controller Tuning by Means of Multi-Objective Optimization Algorithms: A Global Tuning Framework

A holistic multi-objective optimization design technique for controller tuning is presented. This approach gives control engineers greater flexibility to select a controller that matches their specifications. Furthermore, for a given controller it is simple to analyze the tradeoff achieved between conflicting objectives. By using the multi-objective design technique it is also possible to perform a global comparison between different control strategies in a simple and robust way. This approach thereby enables an analysis to be made of whether a preference for a certain control technique is justified. This proposal is evaluated and validated in a nonlinear multiple-input multiple-output system using two control strategies: a classical proportional-integral-derivative control scheme and a feedback state controller.

Automatic segmentation and 3D reconstruction of intravascular ultrasound images for a fast preliminar evaluation of vessel pathologies

Intravascular ultrasound (IVUS) imaging is used along with X-ray coronary angiography to detect vessel pathologies. Manual analysis of IVUS images is slow and time-consuming and it is not feasible for clinical purposes. A semi-automated method is proposed to generate 3D reconstructions from IVUS video sequences, so that a fast diagnose can be easily done, quantifying plaque length and severity as well as plaque volume of the vessels under study. The methodology described in this work has four steps: a pre-processing of IVUS images, a segmentation of media-adventitia contour, a detection of intima and plaque and a 3D reconstruction of the vessel. Preprocessing is intended to remove noise from the images without blurring the edges. Segmentation of media-adventitia contour is achieved using active contours (snakes). In particular, we use the gradient vector flow (GVF) as external force for the snakes. The detection of lumen border is obtained taking into account gray-level information of the inner part of the previously detected contours. A knowledge-based approach is used to determine which level of gray corresponds statistically to the different regions of interest: intima, plaque and lumen. The catheter region is automatically discarded. An estimate of plaque type is also given. Finally, 3D reconstruction of all detected regions is made. The suitability of this methodology has been verified for the analysis and visualization of plaque length, stenosis severity, automatic detection of the most problematic regions, calculus of plaque volumes and a preliminary estimation of plaque type obtaining for automatic measures of lumen and vessel area an average error smaller than 1mm(2) (equivalent aproximately to 10% of the average measure), for calculus of plaque and lumen volume errors smaller than 0.5mm(3) (equivalent approximately to 20% of the average measure) and for plaque type estimates a mismatch of less than 8% in the analysed frames.

Chemosterilants as control agents of Ceratitis capitata (Diptera: Tephritidae) in field trials.

Lufenuron is a chitin synthesis inhibitor, which is able to impede Mediterranean fruit fly, Ceratitis capitata (Wiedemann), reproduction. In laboratory trials, following ingestion of lufenuron, the eggs laid by female Ceratitis capitata were prevented from hatching. In field trials in Valencia, Spain, lufenuron showed its effectiveness by reducing C. capitata wild populations and its continuous application to several generations of fruit fly resulted in increased pest control. This field trial was conducted in an isolated valley some 80 ha in size, over a continuous four-year period. In order to maintain the sterilizing effect in the field throughout the whole year, a new lufenuron bait gel was developed. This bait gel was introduced in to delta traps suspended in trees at a density of 24 traps ha-1, and these traps were replaced once a year during the field trial. Monitoring of the adult C. capitata population was conducted to assess the effects of the chemosterilant treatment. In the first year of treatment with sterilizing traps, a reduction of the C. capitata population was observed, indicating that the traps reduce the population right from the first generation. In the second, third and fourth years, a continuous and progressive reduction of the adult Mediterranean fruit fly population was observed. Therefore, the successive application of chemosterilization treatment has a cumulative effect on reducing the fly population year after year. Aerial treatment using malathion does not produce this cumulative effect, and consequently every year it is necessary to start again with the same number of flies as the year before. The possibility of using the chemosterilant method alone or combined with the sterile insect technique is discussed.

Genetic algorithms optimization for normalized normal constraint method under Pareto construction

This paper presents the resolution of multiobjective optimization problems as a tool in engineering design. In the literature, the solutions of this problems are based on the Pareto frontier construction. Therefore, substantial efforts have been made in recent years to develop methods for the construction of Pareto frontiers that guarantee uniform distribution and exclude the non-Pareto and local Pareto points. The normalized normal constraint is a recent contribution that generates a well-distributed Pareto frontier. Nevertheless, these methods are susceptible of improvement or modifications to obtain the same level of results more efficiently. This paper proposes a modification of the original normalized normal constraint method using a genetic algorithms in the optimization task. The results presented in this paper show a suitable behavior for the genetic algorithms method compared to classical Gauss-Newton optimization methods which are used by the original normalized normal constraint method.

Evaluation of lufenuron as a chemosterilant against fruit flies of the genus Anastrepha (Diptera: Tephritidae)

BACKGROUND Chemosterilisation with lufenuron bait stations is a recently developed technique that is being implemented for Ceratitis capitata Wiedemann control. The aim of this work was to evaluate the chemosterilising effect of lufenuron against four economically important Latin American fruit flies species: Anastrepha ludens (Loew.), A. obliqua Macquart, A. serpentina Wiedemann and A. striata Schiner (Diptera: Tephritidae) in order to design a similar strategy for their control. RESULTS Sexually mature adults were treated by ingestion with concentrations ranging from 0.1 to 30.0 mg g(-1) of lufenuron in the diet. In addition, conspecific crosses with only one of the sexes being treated (30.0 mg g(-1)) were performed in order to appraise the contribution of each sex to the sterilising effect. In all cases, fecundity was not affected by the treatments, as opposed to fertility where all Anastrepha species studied were significantly affected, although to different extents. The conspecific crosses showed that treated males of A. ludens, A. obliqua and A. serpentina were not able to transmit the sterility to their respective untreated females. Only in the case of A. striata did crossing treated males with untreated females significantly reduced egg hatch. CONCLUSION Although further investigations are required, the present results demonstrate that the use of lufenuron for controlling A. striata could be potentially viable.

Field Efficacy of a Metarhizium anisopliae-Based Attractant-Contaminant Device to Control Ceratitis capitata (Diptera: Tephritidae)

ABSTRACT Biological control of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) using entomopathogenic fungi is being studied as a viable control strategy. The efficacy of a Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae)-based attractant—contaminant device (ACD) to control C. capitata was evaluated in a medium-scale (40 ha) 2-yr field trial using a density of 24 ACD per ha. Results showed that this density was adequate to efficiently reduce fruitfly populations and that the inoculation dishes (IDs) needed replacing mid-season to provide protection for the entire season. In this study, fungal treatment was even more effective than conventional chemical treatment. Population dynamics in fungus-treated fields along with the infectivity study of field-aged IDs in the laboratory found that the ACD remained effective for at least 3 mo. The results suggest M. anisopliae-based ACD can be used to control C. capitata in the field. The implications of its use, especially as a tool in an integrated pest management program, are discussed.

Chemosterilant Bait Stations Coupled with Sterile Insect Technique: An Integrated Strategy to Control the Mediterranean Fruit Fly (Diptera: Tephritidae)

ABSTRACT During 2008 and 2009, the efficacy of the combination of two Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), control techniques, sterile insect technique (SIT) and a chemosterilant bait station system (Adress), was tested in three crops: citrus (Citrus spp.), stone fruit (Pranus spp.), and persimmon (Diospyros spp.). Two thousand sterile males were released per ha each week in the whole trial area (50,000 ha, SIT area). For 3,600 ha, within the whole trial area, 24 Adress traps per ha were hung (SIT + Adress area). Ten SIT + Adress plots and 10 SIT plots in each of three different fruit crops were arranged to assess Mediterranean fruit fly population densities and fruit damage throughout the trial period. To evaluate the efficacy of each treatment, the male and female populations were each monitored from August 2008 to November 2009, and injured fruit was assessed before harvest. Results showed a significant reduction in the C. capitata population in plots treated with both techniques versus plots treated only with the SIT. Likewise, a corresponding reduction in the percentage of injured fruit was observed. These data indicate the compatibility of these techniques and suggest the possibility of using Adress coupled with SIT to reduce C. capitata populations in locations with high population densities, where SIT alone is not sufficiently effective to suppress fruit fly populations to below damaging levels.

Well-Distributed Pareto Front by Using the \epsilon \hskip-0.9em \nearrow \hskip-0.4em-MOGA Evolutionary Algorithm

In the field of multiobjective optimization, important efforts have been made in recent years to generate global Pareto fronts uniformly distributed. A new multiobjective evolutionary algorithm, called \(\epsilon \hskip-0.9em \nearrow \hskip-0.4em-MOGA\), has been designed to converge towards \(\mathbf{\Theta}_P^*\), a reduced but well distributed representation of the Pareto set Θ P . The algorithm achieves good convergence and distribution of the Pareto front J(Θ P ) with bounded memory requirements which are established with one of its parameters. Finally, a optimization problem of a three-bar truss is presented to illustrate the algorithm performance.In the field of multiobjective optimization, important efforts have been made in recent years to generate global Pareto fronts uniformly distributed. A new multiobjective evolutionary algorithm, called ∉-MOGA, has been designed to converge towards ΘP*, a reduced but well distributed representation of the Pareto set ΘP. The algorithm achieves good convergence and distribution of the Pareto front J(ΘP) with bounded memory requirements which are established with one of its parameters. Finally, a optimization problem of a three-bar truss is presented to illustrate the algorithm performance.

A Smart-Distributed Pareto Front Using the ev-MOGA Evolutionary Algorithm

Obtaining multi-objective optimization solutions with a small number of points smartly distributed along the Pareto front is a challenge. Optimization methods, such as the normalized normal constraint (NNC), propose the use of a filter to achieve a smart Pareto front distribution. The NCC optimization method presents several disadvantages related with the procedure itself, initial condition dependency, and computational burden. In this article, the epsilon-variable multi-objective genetic algorithm (ev-MOGA) is presented. This algorithm characterizes the Pareto front in a smart way and removes the disadvantages of the NNC method. Finally, examples of a three-bar truss design and controller tuning optimizations are presented for comparison purposes.