"Seasonal occurrences and the number of generations of cotton bollworm, Helicoverpa armigera (Huebner) in Nara prefecture [Japan]."
2002
"Imura, T. (Nara-ken. Agricultural Experiment Station, Kashihara (Japan)) | Kunimoto, Y. | Matsumura, M. "
"Seasonal occurrence and the number of generations of cotton bollworm, Helicoverpa armigera (Huebner) were investigated in Nara prefecture. Seasonal occurrences of adults were investigated by sex-pheromone trap reserch at 3 regions from 1998 till 2001. The number of generations estimated by the outdoor condition rearing. H. armigera completed 4 or 5 generations per year and 6 peaks of adult emerging were occured. First to forth peaks shown by sex pheromone trap reseach were agree with adult emerging periods of overwintering generations, first, second and third generations respectively. Fifth and sixth peak were formed by a part of forth generation adults. Generation time of second and third genaration were about 1 month but after forth generation, growth period delaied and emerging period were getting longer. Some individuals of forth generation were emerging and laied eggs of fifth generation in before the end of year but the rest of forth generation entered into overwintering diapause in the pupal stage. Fifth generation individuals laied before the first half of October enterd into overwintering diapause in the pupal stage but after the second half were dead by low temperture before pupation."
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