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Tropentag, October 7 - 9, 2008 in Hohenheim

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Susceptibility of Different Stages of the Mediterranean Fruit Fly Ceratitis capitata, to Entomopathogenic Fungus Lecanicillium muscarium

Ali Ali, Helga Sermann, Carmen Büttner

Humboldt-Universität zu Berlin, Institute for Horticultural Sciences, Phytomedicine, Germany


This study determined the pathogenicity of L. muscarium to eggs, larvae and adults of C. capitata under laboratory conditions.

Four ml of suspension of L. muscarium (4×107 conidia ml-1) was applied on sterile filter paper in Petri dishes and water for the control respectively. Eggs were placed on the infected filter paper and incubated at 20 °C. After 24 h 10 contaminated eggs were transferred on artificial diet and incubated at 25°C and 70% R.H (5 replicates).
The entomopathogenic fungus was low pathogenic to the eggs, although the differences in the mortality between the fungus (24%) and the control (8%) was significantly.

To evaluate the susceptibility of the old larvae, plastic container (3,8 cm diam. × 2,8 cm high) were filled with 10 g dry soil and sprayed with 1 ml suspension (4.3×106 spores/cm2) on the soil surface using a small dash bottle. On each container 10 old larvae were transferred on the treated soil in the container. Container were incubated at 25°C and 70% R.H (5 replicates).
L. muscarium reduced emergence of adult at 46% in comparison to the control with 74%. In the treatment 54% were dead but 40% of those were infected probable with L. muscarium.

To evaluate the susceptibility of adults in plastic container (5 cm diam. × 3,5 cm high) were filled a small layer of soil and 15 ripe pupae spread uniformly on the surface. Above it 2 to 3 cm layer of soil were filled again. Three ml suspension (3×107conidia ml-1) was sprayed on the soil surface. Incubation took place (5 replicates) at 25° C, and 70% RH. All emerged adults were transferred daily to cages with water and dry yeast extract-sucrose. All dead flies were disinfected, placed on water agar in Petri dishes and incubated at 20°C.
The fungus was pathogen to the flies. In course of experiment 65,6% of flies were dead in comparison to the control with 13,2%. 40,6% of emerged flies was moulded.

These results indicate, that L. muscarium is pathogenic against C. capitata. From all developmental stages the adults are mostly susceptible against this entomopathogenic fungus.

Keywords: Ceratitis capitata, developmental stages , lecanicillium muscarium, mortality

Contact Address: Ali Ali, Humboldt-Universität zu Berlin, Institute for Horticultural Sciences, Phytomedicine, Lentzeallee 55-57, 14195 Berlin, Germany, e-mail: aligermany80@yahoo.de

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