Conidia of Metarhizium flavoviride were hermetically stored at 13.7% moistu
re content with four constant (20, 30, 40 and 50 degrees C) and six fluctua
ting temperature regimes (20:30, 20:40, 20:50, 30:40, 30:50 and 40 degrees
C:50 degrees C, all 24 h:24 h) for up to 119 days. Survival of conidia stor
ed at both constant and fluctuating temperatures conformed to cumulative ne
gative normal distributions and all 10 survival curves could be constrained
to a common origin. The effect of constant storage temperature on conidia
longevity was quantified satisfactorily by a negative curvilinear semi-loga
rithmic relation developed previously, in which the estimates of the consta
nts C-H and C-Q were 0.0176 (SE 0.0013) and 0.000703 (SE 0.000019), respect
ively. The fitted relation at constant temperatures showed that Q(10) for l
oss in conidia viability increased the warmer the temperature regime. The e
ffect of the cooler temperature of each fluctuating temperature regime on c
onidia longevity was small, since the effective temperature of each regime
for loss in conidia viability was always much warmer than the mean. Conidia
were also stored in two further regimes: at 30 degrees C for 21 or 35 days
before transfer to 50 degrees C. The standard deviations of the conidia su
rvival curves at 50 degrees C were unaffected by the duration of previous s
torage at 30 degrees C. Thus change in temperature per se had no effect on
conidia survival: conidia survival curve slopes were solely dependent upon
the contemporary storage environment. Approaches are developed in order to
predict loss of conidia viability in fluctuating temperature storage enviro
nments, and the predictions compared against independent observations.