Journal of Economic Entomology (2015) 108, 629-639

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M.A. Silva, G.C.D. Bezerra-Silva, J.D. Vendramim, M.R. Forim and I.C.G. Sá (2015)
Threshold concentration of limonoids (Azamax) for preventing infestation by Mediterranean fruit fly (Diptera: Tephritidae)
Journal of Economic Entomology 108 (2), 629-639
Abstract: This study identified the threshold concentration of limonoids for the complete inhibition of oviposition of Ceratitis capitata (Wiedemann) in grapes 'Itália.' Choice and no-choice experiments with the insect were performed. The three no-choice bioassays were conducted following a completely randomized design with 18 treatments (three densities of insects [one, two, or three females] × five concentrations of limonoids and control) and 20 replicates. In a free choice bioassay, two fruits per cage (a treatment grape and a control) were provided for ovipositing. Three densities of insects (one, two, or three females) were used, with 15 replicates. Bioassays were conducted at 25 ± 2°C, 60 ± 10% relative humidity, and a photoperiod of 14:10 (L:D) h. The inhibition of oviposition of C. capitata was concentration dependent, with infestation occurring at lower concentrations of azadirachtin (+ 3-tigloylazadirachtol) and complete inhibition occurring at concentrations at or exceeding 100 ppm azadirachtin (+28.5 ppm of 3-tigloylazadirachtol), maintaining protective effects even at the most densely populated treatment (three females per fruit). When the pest had a free choice of host grapes (treatment vs. control), severe inhibition was observed at concentrations >50 ppm azadirachtin (+14.3 ppm of 3-tigloylazadirachtol). We conclude that a threshold concentration of 100 ppm azadirachtin (+28.5 ppm of 3-tigloylazadirachtol) is capable of preventing grape infestation. This concentration is likely to provide a reliable level of protection, as the experimental population density of three females per fruit usually does not occur in the field and wild flies usually have more host options.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Marcio Alves Silva, José Djair Vendramim

Research topic(s) for pests/diseases/weeds:
control - general

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Ceratitis capitata