The virulence of two products of the fungus Beauveria bassiana (LCPP and Bassianil) on adult Anastrepha ludens (Loew) (Diptera: Tephritidae) and their effect on the mating performance of infected males was evaluated in laboratory and field cage tests. The horizontal transmission capacity of the fungus during copulation or attempted copulation also was quantified using inoculated males as well as the impact of infection on female fecundity and longevity. Both fungal products were found to be highly virulent (LCPP, mortality = 98.7% at 1 x 10(8) conidia per ml, LT50 = 4.20 d, LC50 = 9.35 x 10(5) conidia per ml; Bassianil, mortality = 99.3% at 1 X 10(8) conidia per ml, LT50 = 4.04 d, LC50 = 2.69 x 10(7) conidia per ml). Mating success of inoculated males was not affected compared with the control group during the 3 d postinoculation. Horizontal transmission to females during the first day was 80.6 and 84.3% through mating and 15.4 and 21.6% through attempts to mate and contact during courtship for the LCPP and Bassianil products, respectively. The fertility of infected females was notably reduced, and longevity did not extend beyond 15 d. Our results suggest the possibility of using sterile flies as fungus vectors in sterile insect technique programs, but the potential benefits and shortcomings of this approach require further investigation.
The demographic changes in Anastrepha obliqua (Macquart) (Diptera: Tephritidae) throughout laboratory colonization were characterized over the course of 11 generations. Four significant changes were determined. The first change was a reduction in the preoviposition period from the G(p) to G(1). The second was that wild female flies had difficulty ovipositing in an artificial substrate, yielding the lowest fecundity rates observed throughout the experiment. The third significant change was a decrease in longevity and life expectancy from G(p) to G(1), which then continued to decrease with successive generations. This resulted in a lab strain with high fecundity limited to a short period of oviposition. The last significant change was a reduction in larval and pupal weight. In addition, larval recovery decreased from G(p) to G(1) but displayed rapid recovery over the course of generations. There was no change in adult emergences for all generations, and flight ability increased with successive generations. These changes were correlated with demographic parameters, indicating that the increased investment in early age reproduction incurs costs such as a reduction in life expectancy or fecundity later in life. This trend was also correlated with an increase in early fecundity and reduction in the oviposition period.
Although further investigations are required, the present results demonstrate that the use of lufenuron for controlling A. striata could be potentially viable.
This study reports the pathogenicity of three formulations of Beauveria bassiana (Balsamo) Vuillemin (Hypocreales) – Bb‐ET, GHA, and Bb‐AES – and their application in panel‐type and cylinder‐type autoinoculation devices, and using sterile males as vectors for the control of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in coffee‐producing areas of the Central Highlands of Guatemala. Using sterile adults of C. capitata under laboratory bioassays, mean lethal concentrations (LC50) of 1.4 × 107, 2.4 × 106, and 8.2 × 105 conidia ml−1, and median survival times of 4.1 ± 0.1, 4.2 ± 0.1, and 3.8 ± 0.1 days, were recorded for the strains GHA, Bb‐AES, and Bb‐ET, respectively. These values indicate that the three strains were sufficiently pathogenic and that their period of biological activity was considered adequate for using sterile flies as vectors of the inoculum. Observed percentages of sporulated wild C. capitata flies were 57.3, 44.7, and 44.3% for sterile fly vectors, panel devices, and cylinder devices, respectively. The total population reduction at the end of the study period was over 90% for the three treatments. Our results show that sterile males used as vectors or disseminator devices may represent a new control method for area‐wide integrated management of Mediterranean fruit flies. The potential of this new approach and its integration with other control methods, including the sterile insect technique, is discussed.
Sterile Mediterranean fruit fly, Ceratitis capitata (Wied.), males were evaluated as vectors to spread Beauveria bassiana (Bals) conidia to wild C. capitata populations under field conditions. The inoculated sterile males were released by air, using the chilled adult technique over 7000 ha of coffee growing in Chimaltenango, Guatemala, Central America. The impact of releases was determined using dry traps baited with a food attractant. The effects of these releases on Apis mellifera, Linnaeus (honey bee), Hypothenemus hampei, Ferrari (coffee berry borer) and the parasitic mite Varroa destructor (Oudeman) were also evaluated. Inoculated sterile males were able to transmit fungal spores to 44% of the wild C. capitata flies captured in traps, which likely were infected through intra-and intersexual interactions during leks, mating or mating attempts. There was no transmission of the fungal spores to non-target insect species such as coffee berry borer, honey bees or varroa. We conclude that sterile males of Mediterranean fruit fly inoculated with B. bassiana can act as effective vectors of conidia to wild populations, constituting a safe, environmentally friendly and selective alternative for suppressing the medfly under a Sterile Insect Technique-based IPM approach.
The objective of this study was to determine the relationship between residual time of GF-120 (spinosad) treatment and mortality in three species of Anastrepha Schiner. Concentrations of 96, 72, 48, and 24 ppm were aged on mango leaves under field conditions for 0, 3, 7, 10, 14, 17, and 21 d after application. We found that Anastrepha ludens, A. obliqua, and A. serpentina were highly sensitive to spinosad. The effects of spinosad were not reduced over the 4 d after the initial application, even at a concentration of 24 ppm. Mortality at 14 d after the application of 72 and 96 ppm of spinosad was similar in each of the three fruit fly species. In addition, we found that 24 ppm of spinosad was consumed the most by each species even though no direct relationship between the rate of consumption per female and the dose of the product was observed, in this test, higher consumption of active ingredient was observed at a concentration of 72 ppm, for A. ludens, 48 ppm for A. obliqua, and 96 ppm for A. serpentina. Our results suggest that a spinosad concentration of 72 ppm may effectively control these pests for at least 10 d under field conditions.
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