Bioassay of conidial thermotolerance of Beauveria bassiana strains from different hosts and geographic origins

In order to search for fungal biocontrol agents adaptable to pest control during hot summer of southern China, aerial conidia of 12 Beauveria bassiana strains from different host insects and geographic origins were separately suspended in a solution containing 2% sucrose and 0.5% peptone. For each s...

Full description

Saved in:
Bibliographic Details
Main Authors: LI Hong-wen, FENG Ming-guang
Format: Article
Language:English
Published: Zhejiang University Press 2008-03-01
Series:浙江大学学报. 农业与生命科学版
Subjects:
Online Access:https://www.academax.com/doi/10.3785/j.issn.1008-9209.2008.02.006
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In order to search for fungal biocontrol agents adaptable to pest control during hot summer of southern China, aerial conidia of 12 Beauveria bassiana strains from different host insects and geographic origins were separately suspended in a solution containing 2% sucrose and 0.5% peptone. For each strain, the conidial suspension of 1 mL in a 10 mL glass tube was exposed to the thermal stress of 48 ℃in water bath. The residual viability of the conidia after a given period of exposure was measured as survival index, which was defined as the ratio of their germination rate (observed after 24 h incubation at 25 ℃) over the germination rate of unexposed conidia (blank control). Observations made at 6 min intervals during the thermal stress fitted well to a logistic equation (r<sup>2</sup>&gt;0.98), which yielded the estimates of median lethal time (LT<sub>50</sub>) depicting fungal thermotolerance. As a result, the LT<sub>50</sub> estimates fell in a range of 6.7-21.2 min, being significantly different among the 12 strains tested. The method developed is simple and convenient for the evaluation of conidial thermotolerance, and could be useful for screening of thermotolerable fungal biocontrol agents and enhancement of their field persistence.
ISSN:1008-9209
2097-5155