Effects of Incubation Temperature on the Dose–Survival Time Relationship of Trichoplusia ni Larvae Infected with Autographa Californica Nucleopolyhedrovirus

The interaction between virus multiplication and host development was studied by determining the survival time of Trichoplusia ni larvae inoculated with a wide range of doses of Autographa californica nucleopolyhedrovirus and incubated at five different temperatures spanning the biologically relevant range. The results support earlier findings that the course of baculovirus infection follows the mathematical description of the birth–death model. Both in vivo rate of virus increase and larval growth rate increased linearly with increasing temperature from 14 to 29°C; developmental zeros for virus replication and larval growth were estimated from these data to be 10.2 and 10.4°C, respectively. The data were used to generate a description of the combined effects of dose and temperature on median survival time at doses greater than the LD50. Implications of the lag times before onset of viral replication and between cessation of replication and larval death with respect to model-based estimation of the critical population level (i.e., amount of virus in the host just prior to death) are discussed.