Biology, population dynamics and management of banana pseudostem borer, Odoiporus longicollis Olivier (Coleoptera: curculionidae) on Lakatan AA, Musa acuminata Colla

The biology and life table study was conducted in the laboratory. The eggs of Odoiporus longicollis hatched in 2-3 days. The average period under each larval instar was observed as follows: first instar 2.22 days; second instar 2.27 days; third instar 2.754 days; fourth instar 3.39 days; and fifth instar 5.89 days. The mean duration of pupal period was recorded as 13.39 days whereas the total developmental period from egg to the emergence of adult was 32.2 days. The highest mortality rate (45.3%) was in the egg stage. Among the larval instars, mortality was highest in the second larval instar (11.0%). The net reproductive rate (Rsubo) of O. longicollis on Lakatan banana was 6.64 female progeny per adult female, and the intrinsic rate of population increase (rsubm) in the present study was 0.033 per day. The generation time (G) was 57.11 days and the doubling time (t) 20.90 days. The high age-specific reproductive values (Vsubx), 1.8 and 1 were observed at between 15 days and 75 days of newly emerged adult females. The population of O. longicollis was higher in June but it was reduced and reached to the lowest density in October 2009. Highest mean number of individuals per plant for all develomental stages of O. longicollis was observed during per flower stage, followed by flowered, stump and maiden. A survey was conducted to understand the common practices of banana growing as well as to explore the knowledge on management of O. longicollis in banana field. Poor crop management and the use of poor suckers were the main sources of weevil infestation in pre-flower stage of banana plant, particularly in rainy season. Chemical insecticides were not applied for management purpose of O. longicollis within survey sites. Fifty four percent of the respondents did not have experience on the management of O. longicollis. The mean numbers of O. longicollis captured in disc type trap was 43.20 percent higher than those captured in split type trap. Monthly injection of 30 ml of thiamethoxam (0.4%) solution provided satisfactory protection from the infestation of O. longicollis. Carbofuran 3G did not hinder the effectiveness of disc type trap.