Biology of Corecoris dentiventris Berg, 1884 (Hemiptera, Coreidae) in tobacco culture (Nicotiana tabacum)

摘要

Corecoris dentiventris Berg, 1884 (HEM., Coreidae) represents a pest in the tobacco culture in Southern Brazil. Nymphs and adults cause the wilting and twisting of the tobacco leaves due to their sucking habit. There are very few works about this species and these are restricted to concise description of the adult morphology, records of host plants and enumeration of injuries. The present investigation aims to study the life cycle of this bug. The experiment was carried out in a tobacco culture (Virginia type, var. K 326) implanted in the experimental area of the Departamento de Fitossanidade of the Universidade Federal do Rio Grande do Sul, in Porto Alegre, RS. The life cycle was studied in field conditions, in nylon cages, from egg clusters oviposited by females of the colonizing generation. The prefered oviposition site was the main vein in the abaxial side of the leaf. The average incubation period was 13.7 ± 0.04 days and the egg viability, 99.63%. The average periods of the different instars of the bug, in days, were: 5.4 ± 0.08, 9.7 ± 0.19, 4.5 ± 0.08, 5.3 ± 0.08, 9.0 ± 0.13 respectively for the first, second, third, fourth and fifth instars. The first instar presented the highest mortality (13.86%). The accumulated mortality of the nymphal phase was 35.29%. The sex ratio was 0.97 males : 1 female.