J. Fargues et al., LEAF CONSUMPTION BY LARVAE OF THE COLORADO POTATO BEETLE (COLEOPTERA,CHRYSOMELIDAE) INFECTED WITH THE ENTOMOPATHOGEN, BEAUVERIA-BASSIANA, Journal of economic entomology, 87(1), 1994, pp. 67-71
In a laboratory feeding experiment, we used a photometric method to st
udy the effect of the entomopathogenic hyphomycete, Beauveria bassiana
(Balsamo) Vuillemin, on foliage consumption by fourth-instar Colorado
potato beetles, Leptinotarsa decemlineata (Say). Three inoculum rates
(10(4), 3 x 10(4), and 10(5) conidia/cm2) were tested, causing time-m
ortality responses ranging from 6 to 12 d. During the first 24 h of ex
posure to any of the three rates, larvae contaminated with B. bassiana
expressed significant phagostimulation, that reached 20%. We found no
significant differences in consumption rates on day 2. After this per
iod, infection caused starvation such that early consumption by inocul
ated larvae was significantly less than that of control larvae. Moreov
er, increasing the fungus rate decreased the length of the feeding per
iod. Finally, the reduction in total food consumption per larva caused
by the B. bassiana treatment was 56.6, 67.8, and 76.2% for the three
rates tested.