Each moth deposits one to five eggs per plant visit and may lay up to 2,000 eggs. Larvae emerge about 4 days later, depending upon temperature. After feeding for 3 weeks, hornworms burrow into the soil and spend 3 weeks after which a new generation of moths emerges. In North Carolina, at least two and one-half generations occur each year. Early generations are potentially damaging to marketable tobacco.
Later ones feed after harvest on noncommercial suckers.
However, these last generations are important because they produce the overwintering pupae. There are a number of natural enemies that help control hornworm populations. Wasps prey on larvae. Offspring emerge from fourth and fifth instar larvae and spin numerous white cocoons on their backs. Bacillus sphingidis White causes hornworm septicemia disease.