Exigências térmicas e estimativa do número de gerações de Argyrotaenia sphaleropa (Meyrick) (Lepidoptera: Tortricidae)

Abstract

Argyrotaenia sphaleropa (Meyrick) is often found attacking Diospyros kaki fruits in southern region of Brazil. Duration and viability of the periods (eggs, larvae and pupae) and lifespan of the pest was studied under laboratory conditions in different temperatures. The experiment was conducted in climatic chambers under 60±10% RH and 14h photophase, at temperatures of 14, 18, 20, 22, 25, 28 and 30°C, using artificial diet. Larval eclosion occurred in 5.9 to 25.4 days and larval period ranged from 13.9 to 91.1 days at 30 and 14°C, respectively. A variation of 6.4 (30°C) to 28.3 (14°C) and 26.5 (30°C) to 143.4 (14°C) days was observed for pupal phase and lifespan. Eggs, larvae and pupae viability was always higher than 75% while the lower total viability was 64.8% at 18°C. For eggs, larvae, pupae and total cycle, the threshold temperature and thermal requirements were respectively 10.8, 10.9, 10.0 and 11.0°C and 104.3, 251.4, 114.9 and 473.3 degree days. For A. sphaleropa the occurrence of the 4.1 and 14.7 generations per year were estimated in the field and in the laboratory (30°C), respectively. Temperatures of 14 and 18°C were less favorable for the insect development, with increase in time of development and decrease in survivorship.