Biology and Seasonal Incidence of Pseudostem Weevil, Odoiporus longicollis Olivier (Coleoptera: Curculionidae) in Sugandhi banana Growing Regions of Northern Karnataka, India

Abstract

Banana is an important fruit crop in India, and the banana pseudostem weevil, Odoiporus longicollis Olivier, is a damaging internal feeder that affects plant vigour and pseudostem health. This study documented the biology and seasonal incidence of the pest in Sugandhi banana under the agro-climatic conditions of Northern Karnataka. Laboratory studies were conducted during 2020–21, while field observations were recorded during 2021–22 and 2022–23 in ratoon banana at Hosur village, Hosapete taluk, Vijayanagar district. Under laboratory conditions, mating was observed 8-9 days after adult emergence and lasted for 3-5 minutes. The mean incubation period was 6.50 days. The insect completed five larval instars, with a total larval duration of 31.50 days. The mean pre-pupal and pupal periods were 5.00 and 19.50 days, respectively. Adult longevity averaged 66.60 days in males and 91.70 days in females. The total life cycle ranged from 121 to 154 days, with a mean duration of 137.50 days. The pre-oviposition period averaged 22.50 days, and fecundity ranged from 12 to 22 eggs per female. Field observations showed that the weevil population and pseudostem damage increased from May onwards and reached peak levels during August and September in both study years. During 2021-22, the maximum weevil population was 6.55 weevils per plant, and the maximum number of bored holes was 10.98 per plant. During 2022-23, the corresponding values were 6.78 weevils and 15.91 bored holes per plant. Rainfall and relative humidity showed positive associations with pest incidence, whereas maximum temperature showed a negative association in 2021-22. The findings indicate that seasonal weather conditions influence the population build-up and damage intensity of O. longicollis in Sugandhi banana.