C. Luz et J. Fargues, TEMPERATURE AND MOISTURE REQUIREMENTS FOR CONIDIAL GERMINATION OF AN ISOLATE OF BEAUVERIA-BASSIANA, PATHOGENIC TO RHODNIUS-PROLIXUS, Mycopathologia, 138(3), 1997, pp. 117-125
The effects of temperature, relative humidity and water activity on ge
rmination of conidia of an isolate of Beauveria bassiana (Bals.) Vuill
. pathogenic to the triatomine vector of Chagas' disease, Rhodnius pro
lixus Stal., were investigated in vitro. Germination occurred at tempe
ratures between 15 degrees C and 35 degrees C under saturated atmosphe
re and the optima ranged from 25 degrees C to 30 degrees C. At the ext
reme temperatures tested (15 degrees C and 35 degrees C) the germinati
on process was delayed, but germination rates reached more than 95%. G
ermination of B. bassiana conidia was strongly affected by moisture co
nditions. The availability of water, in both atmospheric and liquid co
nditions, caused changes in germination times as well as in germinatio
n rates. For example, at 25 degrees C + 0.5 degrees C, germination too
k place within 20 h at 95.5% RH, whereas it needed 72 h of incubation
at 90% RH. Germination times increased as the water activity declined
from 0.96 a(W) to 0.92 a(W). Below 0.92 a(W), no germination was obser
ved after a 72 h incubation time.