Life History and Damage of a New Baradinae Weevil (Coleoptera: Curculionidae) on Amaryllis

Abstract

A small Baradinae weevil that feeds on amaryllis plants has been known in Florida for over 15 years. It is yet to be named taxonomically and its life history has not been studied previously. Observations on weevil damage were made on containerized amaryllis (Hippeastrum hybrids) plants naturally infested in a greenhouse or used for colony rearing. Laboratory studies were conducted at ambient room temperature (75°C) with excised leaves to obtain information on weevil life history. Adults lived about 3 months, and fed on basal versus apical leaf tissue. Females inserted eggs near the thickened leaf base, and eggs were 0.65 ± 0.02 mm long by 0.40 ± 0.01 mm wide. Females laid >400 eggs over their lifetime, with egg production increasing over the first 7 weeks and then tending to decline. Eclosion ranged from 51% for eggs removed from host tissue within 24 h to 84% for eggs removed from host tissue after 24 h of oviposition. In tests with excised leaf tissue, eggs hatched after 7.1 d and larval development was complete after 28.8 d, of which 9.9 d were spent as prepupae. In no-choice tests, survival was lower and pupal developmental time period was longer when larvae were reared on excised bulb versus excised leaf tissue. Although larval development was poorer on bulbs versus leaves in the laboratory studies, in intact plants larvae tunnel through leaf tissue towards the bulb where they feed and complete development. In severe infestations, larvae hollow out the inside of the bulb and may cause plant death. Adult damage is primarily to the foliage through feeding and oviposition. This is the first report to quantify the life history of this weevil.