Author : Suharto

Summary : The population dynamics of H. armigera and H. assulta and their natural enemies on tobacco was conducted in Jember, East Java, Indonesia from January 1993 to March 1994 to determine the spatial and temporal distribution of H. armigera, species composition of genus Helicoverpa in tobacco and alternate host and their natural enemies. The occurrence of H. armigera coincided with the presence of tobacco in the field. The highest number of moth caught in the pheromone traps was observed in South Jember. The distribution of H. armigera was clumped both spatially and temporally. In tobacco field, the proportion of H. armigera in South Jember was higher than in Central and North Jember. H. assulta was more abundant in Central and North Jember. Four parasitoids were found in the tobacco areas in Jember, two tachinids, Carcelia sp. and Palexorista sp., and two ichneumonids, Enicospilus sp. and Campoletis sp. A nuclear polyhedrosis virus was the most frequent pathogen recorded on tobacco budworm throughout the study. In cigar tobacco, the population of Helicoverpa spp. egg started to rise at 4 WAT and increased until it reached a peak at 8 WAT. Larvae were observed in the first week after transplanting and reached the peak of 10 WAAT. The peak population of pupae and adults occurred during the reproductive stage of tobacco. In flue-cured tobacco, the egg and larval population of Helicoverpa spp. and two peaks. The pupa and adult populations were very low throughout the growth stage of the plants. In cigar and flue-cured tobacco, the mirid bug Cyrtopeltis tenuis (Reuter) and Rhinicoris fuscipes (F.) were the most potent natural enemies on tobacco budworm. Among pathogens, NPV infection was the most frequently encountered in the field. Two population tables of Helicoverpa spp. were contructed on cigar tobacco. Both population tables indicated that the highest percentage mortality was on the egg stage due to predation and infertility. Trend index of both population tables were positive.