Efficacy of systemic insecticides to control the Hibiscus Bud Weevil Anthonomus testaceosquamosus (Coleoptera: Curculionidae)

Authors: VARGAS, GERMAN - University Of Florida; VELAZQUEZ HERNANDEZ, YISELL - University Of Florida; Kendra, Paul; REVYNTHI, ALEXANDRA - University Of Florida

Submitted to: Entomological Society of America, Southwestern and Southeastern Branch
Publication Type: Abstract Only
Publication Acceptance Date: 12/21/2021
Publication Date: 3/26/2022
Citation: Vargas, G., Y. Velazquez-Hernandez, P. E. Kendra, and A. M. Revynthi. Efficacy of systemic insecticides to control the Hibiscus Bud Weevil Anthonomus testaceosquamosus (Coleoptera: Curculionidae). Joint meeting of the Entomological Society of America Southeastern Branch and the American Phytopathological Society Caribbean Division. San Juan, PR. 26-30 Mar 2022.

Interpretive Summary:

Technical Abstract: The Hibiscus bud weevil (HBW) is an invasive pest attacking flower buds of hibiscus in south Florida. Since the HBW is a regulated pest by the Florida Department of Agriculture and Consumer Services, Division of Plant Industry (FDACS-DPI), nurseries are required to guarantee that plants are weevil free at shipment. Retailers restrict the use of neonicotinoids, while foliar applications have shown low efficacy. We tested non-neonicotinoid, registered systemic insecticides (spirotetramat, chlorantraniliprole, flupyradifurone and cyantraniliprole) under greenhouse conditions using two approaches, applications prior to infestation (prophylactic) and after infestation (curative). With the prophylactic approach, individual plants were drenched 4 weeks prior to weevil release; whereas with the curative approach, plants were drenched 1 week post weevil release. Observations were made 7, 14, 21, and 28 days after weevil release, taking 5 buds per plant and colleting fallen buds, to count number of eggs, larvae, pupae and feeding holes per bud. With the prophylactic approach, mean number of larvae, eggs and feeding holes were greater in the control (water application) during all observations, with no differences between active ingredients. With the curative approach, no differences were found in the mean number of larvae and other variables after 7 days of weevil release. In general, systemic insecticides are strategic as larvae feed hidden within the buds. A prophylactic approach brings more protection against developing juveniles regardless of the active ingredient. Growers can prevent initial infestations via drench applications of any of these insecticides in early spring when HBW populations are increasing.