Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 47: 3195 - 3204. Published November 29, 2011.
A laboratory assessment of the potential of selected entomopathogenic fungi to control the green leafhopper Empoasca decipiens Paoli (Homoptera: Cicadellidae).
Tounou Agbéko Kodjo1, 2*, Poehling Hans-Michael1, Agboka Komi1, 3, Raupach Katharina1, Zimmermann Gilbert4 and Borgemeister Christian1
1Institute of Plant Diseases and Plant Protection, Hanover University, Herrenhäuser Str. 2, 30419, Hanover, Germany; 2Ecole Supérieure d’Agronomie (ESA), Université de Lomé (UL), BP 1515 Lomé, Togo; 3International Institute of Tropical Agriculture (IITA), Biological Control Centre for Africa, B.P. 08093, Cotonou, Republic of Benin; 4Federal Biological Research Center for Agriculture and Forestry (BBA), Institute for Biological Control, Heinrichstrasse 243, 64287 Darmstadt, Germany.
ABSTRACT
Objective: The present study was conducted to evaluate the effect of selected entomopathogenic isolates on various nymphal stages of the green leafhopper Empoasca decipiens Paoli.
Methodology and results: The efficacy of 5 fungal isolates from the genera of Beauveria, Verticillium, Paecilomyces and Metarhizium to the green leafhopper, E. decipiens nymphs, was tested under laboratory conditions. A single exposure concentration (1 x 107 conidia/ml) assays for each isolate were first conducted by contact with treated disc leaf for 5 min. These were followed by multiple-concentration assays on three of the most pathogenic isolates using four test concentrations ranging from 1 x 103 to 1 x 106 conidia/ml. All isolates proved to be highly virulent to late fifth-instar nymphs of E. decipiens, with mortality ranging from 60 to 98% and the mean survival time (MST), from 4.30 to 6.09 days. Among the tested isolates, three isolates, M. anisopliae (Ma43), B. bassiana (Bba113) and P. fumosoroseus (Pfr12) were the most pathogenic to the nymphs, resulting in significantly higher mortality and lower MST values. In the multiple-concentration assays, nymphal mortality was dose-dependent. The LC50 values ranged from 0.8 to 5.0 x 105 conidia/ml with the third- and fifth-instar nymphs being more susceptible than the first-instar. All tested strains were able to complete their life cycle by forming conidiospores on the dead insects; in general one to two days after the host had died.
Conclusion and application of findings: Our current study has identified virulent isolates of M. anisopliae, P. fumosoroseusand B. bassiana,the first two being commercially available, and that are good candidates for further development as biological control agents for E. decipiens.
Key Words: Empoasca decipiens, biological control, Beauveria bassiana, Metarhizium anisopliae, Paecilomyces fumosoroseus, Verticillium lecanicillium
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