Seasonal abundance and life tables of the cotton bollworm, Heliothis armigera (Hubner) (Lepidoptera: Noctuidae), at Kamphaeng Saen campus, Nakhon Pathom
1994
Choosang Pangwangthong
Seasonal abundance of Heliothis armigera (Hubner) at Kamphaeng Saen, Nakhon Pathom was studied in 1990-92 by using pheromone traps. The insects were found in abundant throughout the year with at least seven generations. There were more moths caught from traps near the host plants than from all other traps over the campus area. No correlations were found between moth catches and either weather data or egg counts on the host plants. Ten cohost life tables were constructed from field samplings with the assessment of age-specific mortalities. Key factor analysis of the life tables indicated that the mortality in the fifth-sixth instar larvae contributed most to population changes. Rainfall accounted for the main mortality of the egg stage, while the unidentified factors were major causes of larval mortality. Pupal mortality came from bacterial diseases, nuclear polyhedrosis virus, and nematodes, Heterorhabditis spp. Test of density-dependent relationships showed that most age-specific mortalities acted like density-independent fashions except during the first-second instars in which a density-dependent effect was found.
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