Journal of Plant Diseases and Protection (2006) 113, 74-80
C. Sengonca, M. Thungrabeab and P. Blaeser (2006)
Potential of different isolates of entomopathogenic fungi from Thailand as biological control agents against western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)
Journal of Plant Diseases and Protection 113 (2), 74-80
Abstract: The present study aimed to investigate the potential of 41 entomopathogenic fungal isolates, belonging to 25 species from 11 genera isolated from different hosts in Thailand, as biological control agents against the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Firstly, pathogenicities of all isolates were assessed with single concentration against first instar larvae of F. occidentalis . The results showed that 37 out of 41 isolates, belonging to Akanthomyces sp. , Aschersonia spp. , Beauveria spp ., Cordyceps sp. , Hirsutella spp., Metarhizium spp., Paecilomyces spp. , Torrubiella petchii and Verticillium spp., were pathogenic to F. occidentalis , while Hynennostilbe sp., Torrubiella tenuis, Hypocrella discoidea and Cordyceps pseudomilit were non-pathogenic. In general, the pathogenicities of all fungi varied significantly according to the fungal isolate, and could be classified into three pathogenicity levels. High pathogenicity level contained 14 isolates: six isolates of Beauveria , four isolates of Metarhizium, three isolates of Paecilomyces and one isolate of Cordyceps were identified as virulent isolates.
Secondly, the 14 virulent isolates were screened with multiple concentrations against the first instars larvae. It was found that LC50 values of the isolates varied considerably among fungal isolate, e.g. the LC50 values of Beauveria spp. ranged from 2.39 × 10 to 5.89 × 10 conidia/ml, Metarhizium spp. from 2.00 × 10 to 5.00 × 10 conidia/ml, Paecilomyces spp. from 3.89 × 10 to 5.49 × 10 conidia/ml, and Cordyceps sp. LC50 was 4.67 × 10 conidia/ml. Five isolates with LC50 lower than 6.61 × 10, i.e. two isolates of B. bassiana , two isolates of Metarhizium and one isolate of P. fumosoroseus displayed highest virulence isolates.
Finally, the efficiency of the isolates with high virulence was investigated against various developmental stages of F. occidentalis. The virulence of these five entomopathogenic fungi differed at different developmental stages of F. occidentalis . The susceptibility of developmental stages to the entomopathogenic fungi decreased from larvae over pupae to adults.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Cetin Sengonca, Peter Blaeser
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Frankliniella occidentalis | ||||
| Beauveria bassiana (entomopathogen) | Frankliniella occidentalis | Thailand | ||
| Cordyceps fumosorosea (entomopathogen) | Frankliniella occidentalis | Thailand | ||
| Torrubiella petchii (entomopathogen) | Frankliniella occidentalis | Thailand |
