Experimental and Applied Acarology (2008) 46, 247-257

Wei-Bing Shi, Ming-Guang Feng and Shu-Sheng Liu (2008)
Sprays of emulsifiable Beauveria bassiana formulation are ovicidal towards Tetranychus urticae (Acari: Tetranychidae) at various regimes of temperature and humidity
Experimental and Applied Acarology 46 (1-4), 247-257
Abstract: Aerial conidia of Beauveria bassiana in an emulsifiable formulation germinated by >95% after 24 h exposure to the regimes of 20, 25 and 30°C with 51%, 74% and 95% RH. Ovicidal activities of the formulation towards two-spotted spider mite, Tetranychus urticae, were assayed at the concentrations of 0, 18, 160 and 693 conidia mm⁻² sprayed separately onto faba bean leaves including 39 (25-76) eggs per capita. All the sprayed eggs on the leaves were directly exposed to the different regimes for hatch after 24 h maintenance in covered Petri dishes. Generally, hatched proportions increased over post-spray days and decreased with the elevated fungal concentrations; no more eggs hatched from day 9 or 10 onwards. Based on the counts of the hatched/non-hatched eggs in the different regimes, the final egg mortalities were 15.0-40.4%, 48.9-66.6% and 62.9-87.5% at the low, medium and high concentrations, respectively, but only 5.6-11.3% in blank controls. The RH effect on the fungal action was significant at 20 and 25°C but not at 30°C whereas the effect of temperature was significant at 51% and 74% RH but not at 95% RH. Probit analysis of the egg mortalities versus the fungal sprays generated median lethal concentrations (LC₅₀) of 65-320 conidia mm⁻² at all the regimes, and of only 65-78 conidia mm⁻² at 25-30°C with 74-95% RH. The results highlight ovicidal activities of the emulsifiable formulation against the mite species at the tested regimes and its potential use in spider mite control.
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Link to article at publishers website
Database assignments for author(s): Shu-Sheng Liu

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus urticae
Beauveria bassiana (entomopathogen)	Tetranychus urticae