Plant host effect on the development of Heliothis virescens F. (Lepidoptera: Noctuidae).

Heliothis virescens F. is an important polyphagous pest that can develop on >100 plant species, including 20 economic crops. Populations of this insect are believed to be locally maintained on a few crops and weed hosts in Washington County, MS. To find the intrinsic value of these plants for the development of H. virescens populations, we fed different laboratory and wild colonies with fresh and lyophilized plant tissue under a constant temperature. Development time of this insect under laboratory conditions varied up to 10 d between plant hosts and was dependent on the type of plant tissue provided: fresh or lyophilized. Life table parameters such as net reproductive rate, finite rate of increase, and generation time indicated that Trifolium repens, a wild host growing around agricultural fields year round, could be one of the most suitable local plant hosts for the development of H. virescens. Two species of Geranium, previously reported as the source of the first H. virescens generation in the region, had lower intrinsic value as a food source than did T. repens. Gossyipium hirsutum, perhaps the most important crop source of H. virescens in the region, produced low net reproductive rate and finite rate of increase parameters. Sampling conducted in agricultural fields during 2006 and 2007 found no larvae on the above mentioned wild hosts as it was previously reported. Results indicated that H. virescens populations in this region were not supported by the wild plant species growing around agricultural fields during the time when the survey took place.