Originating in northeastern Mexico and southern Texas, the hibiscus bud weevil (HBW), Anthonomus testaceosquamosus Linell 1897, was discovered infesting China rose hibiscus (Hibiscus rosa-sinensis L.) in south Florida in May 2017. Although the biologies of the congeneric boll weevil, A. grandis Boheman 1843, and pepper weevil, A. eugenii Cano 1894 are well documented, no data are available regarding the biology of HBW. Here, we present a comprehensive study on the biology of this pest when reared at 10, 15, 27 and 34 °C and on different food sources. This weevil has three larval instars and its life cycle was completed only at 27 ± 1 °C. Weevil development was similar on an artificial diet when compared with a diet of hibiscus buds. Adult HBW could survive solely on pollen, but reproduction did not occur. Without water, HBW survived for ≈15 days; survival times reached nearly 30 days when water was accessible. Our results suggest that if left unmanaged, HBW has the potential to cause significant economic damage to the hibiscus industry. Given that a comprehensive understanding of a pest’s biology is critical for development of effective integrated pest management, our results provide a foundation for future research endeavors to mitigate the impact of this weevil in south Florida.

In 2017, the hibiscus bud weevil (HBW), Anthonomus testaceosquamosus Linell (Coleoptera: Curculionidae), was found outside of its native range of Mexico and Texas, infesting hibiscus plants in Florida. Therefore, we selected 21 different insecticide and horticultural oil products to evaluate their effects on the reproductive rate, feeding, and oviposition behavior of the HBW. In laboratory experiments, significant mortality was observed in adult weevils exposed to diflubenzuron-treated hibiscus leaves and buds, and hibiscus buds treated with diflubenzuron contained the fewest number of eggs and feeding/oviposition holes. Among horticultural oil products, significant mortality was only observed in experiments in which adult weevils were directly sprayed (direct experiments). Pyrethrins and spinetoram plus sulfoxaflor reduced the oviposition rate and caused significant mortality in direct experiments. Diflubenzuron, pyrethrins, spinetoram plus sulfoxaflor, and spirotetramat were further tested via contact toxicity experiments and greenhouse experiments. Contact toxicity experiments demonstrated that the tested insecticides (except diflubenzuron) were highly toxic to HBW adults. In greenhouse experiments, only those hibiscus plants treated with pyrethrins had significantly fewer feeding/oviposition holes and larvae within their flower buds when compared to control (water-treated) plants. These results constitute an important first step in the identification of effective chemical control options for the HBW.

The hibiscus bud weevil is an invasive pest that attacks tropical hibiscus. Its management has been challenging due to its cryptic adult and concealed immature stages. We evaluated the efficiency of four systemic insecticides (spirotetramat, chlorantraniliprole, flupyradifurone, and cyantraniliprole) against the pest using two approaches: one applied 4 weeks before infestation (prophylactic) and the other 1 week after (curative). The number of eggs, larvae, and feeding holes per sampled bud were recorded 7, 14, 21, and 28 days after the infestation (prophylactic), and after the application (curative), respectively. In general, a greater number of treatment effects were detected in the prophylactic approach in comparison with those in the curative. With the prophylactic approach, the mean number of larvae and feeding holes per actively growing bud was significantly greater for the control (water) than for all insecticides. Among fallen buds, chlorantraniliprole, cyantraniliprole, and spirotetramat had significantly fewer feeding holes than those in the control. With the curative approach, the mean number of feeding holes was greater in the control with no differences among insecticides. The prophylactic application can effectively suppress initial HBW infestation, in contrast to the curative application targeting already high populations. This provides the opportunity for reducing the impact of this regulated pest in areas of expansion.

The hibiscus bud weevil, Anthonomus testaceosquamosus Linell (Coleoptera: Curculionidae), is an invasive pest of tropical hibiscus, Hibiscus rosa-sinensis L. (Malvaceae). While chemical and biological control alternatives have been identified, the viability of cultural control through sanitation (collecting and destroying dropped buds where larvae complete development) remains to be explored. The impact of adult hibiscus bud weevil infestation on flower bud abortion was studied in a greenhouse. Plants were infested with one mating pair of adult weevils, with non-infested plants as controls. Actively growing buds and dropped buds were counted weekly for four weeks. A subsequent shade house experiment evaluated the effect of sanitation on plant productivity. Groups of ten plants in a tunnel tent were infested with ten hibiscus bud weevil adult mating pairs per tent. Treatments included sanitation (weekly collection of dropped buds for eight weeks) and a no sanitation control. Five actively growing buds per tent were collected in search of eggs and larvae, while counts of actively growing buds and open flowers were recorded per plant. To identify efficient sanitation methods, the time required to remove fallen buds using three methods (manual, vacuum, and blower) was estimated. Hibiscus bud weevil infestation, using two adult weevils per plant, led to a 16-fold increase in bud abortion compared to non-infested plants. Sanitation reduced the proportion of dropped buds by 22 %, while no sanitation plants showed more actively growing buds, suggesting overcompensation in response to abortion. The vacuum method was the most efficient bud removal method tested. Sanitation can be an effective, practical, and complementary measure to reduce hibiscus bud weevil infestation in commercial nurseries.

The hibiscus bud weevil (HBW), Anthonomus testaceosquamosus Linell (Coleoptera: Curculionidae), is a significant threat to tropical hibiscus (Hibiscus rosa-sinensis) in Florida, USA, since its invasion in 2017. As a regulated pest in the state, early detection is crucial. Based on the success of pheromone-based monitoring programs for other weevil pests, such as the boll weevil, cranberry weevil, and pepper weevil, this study explores the potential use of these pheromone lures for early detection of HBW. To account for differences in efficacy based on trap color, height, and design, different pheromone lure sizes (4 mm, 10 mm, full-size), trap types (Yellow sticky trap, Japanese beetle trap, Boll weevil trap), and heights (0 m, 1.1 m) were also tested in this study. In laboratory assays, males and females exhibited higher attraction to full-size cranberry weevil lure discs than other lure size-type combinations. In semi-field trials, yellow sticky traps baited with cranberry weevil lures captured more weevils than Japanese beetle or boll weevil traps baited with cranberry weevil lures, while trap height did not influence HBW capture. In semi-field, 4-choice bioassays, yellow sticky traps baited with cranberry weevil lures captured more HBW compared to yellow sticky traps baited with pepper weevil, boll weevil, or unbaited traps. Further research is required to thoroughly evaluate the cranberry weevil lure’s efficacy in capturing HBW. Our study suggests the potential for utilizing yellow sticky traps baited with lures for early HBW detection and highlights the importance of selecting the appropriate lure, trap type, and height for optimal efficacy.