Population dynamics of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae)

Abstract

The study of the population dynamics of Helicoverpa armigera (Hubner) in Cicer arietinum (chickpea), Lycopersicon esculentum (tomato), Abelmeschus esculentus (okra) and Zea mays (maize) crops revealed that the insect passed through five overlapping generations in a year. The growth of the population of H. armigera and its generation survival were maximum in second generation followed by fourth, third, fifth and first generations. Parasitoids, predators, fungal and viral diseases and abiotic factors were among the various observed mortality factors, although the role of predation was not specifically investigated. The key mortality factor within generation was an unidentified pupal parasitoid. The key mortality factor operating between generations was the variation in natality (log of ratio of maximum potential natality and actual eggs). In spite of the biotic mortality factors operating on H. armigera populations, the number of eggs laid is the most important factor that governs the trend of the population growth in all generations. Therefore, a powerful control measure is necessary by either trapping the adult moths or by cultivating trap crop to distract egg laying for those crops to be protected.