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

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.

Studies on the codling moth (Lepidoptera: Tortricidae) response to different codlemone release rates.

The response of the codling moth (Cydia pomonella L. (Lepidoptera: Tortricidae)) to different emission values of its main pheromone component, 8E,10E-dodecadien-1-ol (codlemone), was investigated in three field trials conducted in plots without mating disruption treatments. Moth catches obtained in traps baited with pheromone dispensers were correlated with the corresponding codlemone release rates by multiple regression analysis. In a preliminary trial conducted in Lleida (NE Spain), a decreasing trend of captures was observed based on increasing pheromone levels. After this, the pheromone release profiles of the pheromone dispensers were studied, in parallel with the field trials, by residual codlemone extraction and gas chromatography quantification. In the trials carried out in Asturias (NW Spain), a correlation between trap catches and emission levels (within the range from 11 to 1,078 µg/d) was found and fitted a logarithmic model. Captures followed a decreasing linear trend in the range of emission rates from 11 to 134 µg/d. Given that release values comprised between 11 and 67 µg/d did not lead to significantly different catches in traps, this emission range could be considered to develop effective formulations for attraction purposes when mating disruption is not acting in the environment.

Advances in the use of trapping systems for Rhynchophorus ferrugineus (Coleoptera: Curculionidae): traps and attractants.

Given the social importance related to the red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae), efforts are being made to develop new control methods, such as the deployment of trapping systems. In this work, the efficacy of a new black pyramidal trap design (Picusan) has been verified in comparison with white and black buckets. In addition, the attractant and synergistic effect of ethyl acetate (EtAc) at different release levels has been evaluated under field conditions. The results show that Picusan traps captured 45% more weevils than bucket-type traps, offering significantly better trapping efficacy. The addition of water to traps baited with palm tissues was found to be essential, with catches increasing more than threefold compared with dry traps. EtAc alone does not offer attractant power under field conditions, and the release levels from 57 mg/d to 1 g/d have no synergistic effect with ferrugineol. Furthermore, significantly fewer females were captured when EtAc was released at 2 g/d. The implications of using EtAc dispensers in trapping systems are discussed.

Chemosterilant bait stations coupled with sterile insect technique: an integrated strategy to control the Mediterranean fruit fly (Diptera: Tephritidae).

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 (Prunus 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.

The first account of the mating disruption technique for the control of California red scale, Aonidiella aurantii Maskell (Homoptera: Diaspididae) using new biodegradable dispensers.

Semiochemical-based pest management programs have been increasingly used to provide environmentally friendly methods for the control of major insect pests. The efficacy of the mating disruption technique has been demonstrated for several moth pests. Unfortunately, not many experiments on mating disruption to control diaspididae species have been documented. In this work, biodegradable dispensers for mating disruption with increasing pheromone loads were used in order to study the potential of this technique for the control of Aonidiella aurantii Maskell. Field trial results demonstrated that dispensers loaded with 50 mg (a.i.) (20 g ha-1) and 100 mg (a.i.) (40 g ha-1) of sex pheromone were the most suitable, achieving significant reductions in male catches, compared to an untreated plot. In treated plots, virtually a 70% reduction in damage to fruit was recorded. Pheromone release profiles of all the dispensers were also studied under field conditions. We found that emission values >250 microg day-1 were the most suitable. This study suggests a new biodegradable dispenser capable of interfering with normal A. aurantii chemical communication. The use of mating disruption as a control method against A. aurantii is discussed.

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.

Implication of SAR of male medfly attractants in insect olfaction.

Medfly (Ceratitis capitata) males are strongly attracted by different compounds, not described as pheromones. The best attractants reported are (+)-alpha-copaene, a sesquiterpene of natural source and (-)-ceralure-B1, a non-natural iodinated cyclohexane ester. Although their origin, atomic composition, chemical and physical properties are rather different, they show similar attraction to medflies. The question of why these compounds, act behaviorally in the same way, has been never addressed in research papers. We show here for the first time that these compounds have quite similar stereochemistry, water accessible surfaces, certain local dipole moments and, to some extent, similar octanol/water partition coefficient (log P). When seven carbons, one oxygen and one iodine belonging to (-)-ceralure-B1 are selectively chosen based on topological homology with (+)-alpha-copaene and are overlaid with nine corresponding carbons of (+)-alpha-copaene, the RMS is 0.367 A. This represents a high degree of steric resemblance. Local dipole moments and charges are similar in those regions where the molecules show topological homologies. Thus, we hypothesize that these two molecules could interact with the same male medfly's odorant receptor(s). The implications of this result in future research in insect olfaction is discussed.