The effect of air-dry storage environment on the longevity of conidia from seven isolates of Beauveria bassiana produced at different times and locations was determined by estimating the parameters of a viability equation. Conidia were stored hermetically at six to 11 moisture contents between 2.3 and 32.0% with one (50±0.5 °C) to five constant temperatures (10, 20, 30, 40 and 50±0.5 °) for various periods up to 372 d and then tested for viability. All isolates behaved similarly (P > 0.25) in terms of the relative effect of moisture content (CW) and temperature (CH and CQ) on conidial longevity; common values were CW = 3.05 (SE = 0.07), CH = 0.0293 (SE = 0.0078), and CQ = 0.00081 (SE = 0.00011). Estimates of the low-moisture-content limit to the negative logarithmic relation between conidial moisture content and longevity were 4.6 and 5.0% at 50° and 40°, respectively, for isolate 198-1140ss, and 5.2 and 5.1% moisture content, respectively, for isolate 197-1111. Absolute longevity (KE) varied considerably (P < 0.005) among isolates, even within an isolate when conidia were produced at different locations. Among the eight samples of seven isolates, two cohorts were identified with respect to KE (P < 0.005): conidia of three isolates which were produced at Ascot had a common estimate of KE of 6.696 (SE = 0.170), whereas those produced at Nairobi or Carolina provided a lower estimate (6.203, SE = 0.029). This difference in KE means that for any given viability period in any given environment, the conidia produced in Ascot provided about three times the longevity of the other samples.
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics
- Plant Science