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ARS Home » Southeast Area » Miami, Florida » Subtropical Horticulture Research » Research » Publications at this Location » Publication #409402

Research Project: Mitigation of Invasive Pest Threats to U.S. Subtropical Agriculture

Location: Subtropical Horticulture Research

Title: Entomopathogenic nematodes to control the hibiscus bud weevil Anthonomus testaceosquamosus (Coleoptera: Curculionidae), above ground and on soil surface

item VARGAS, GERMAN - University Of Florida
item VELAZQUEZ-HERNANDEZ, YISELL - University Of Florida
item GREENE, DANIEL - University Of Florida
item Yang, Xiangbing
item REVYNTHI, ALEXANDRA - University Of Florida

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2024
Publication Date: 2/5/2024
Citation: Vargas, G., Velazquez-Hernandez, Y., Greene, D.A., Yang, X., Revynthi, A.M. 2024. Entomopathogenic nematodes to control the hibiscus bud weevil Anthonomus testaceosquamosus (Coleoptera: Curculionidae), above ground and on soil surface. Biological Control. 69:91–101.

Interpretive Summary: The hibiscus bud weevil (HBW) is a newly invasive pest of hibiscus in south Florida in 2017 and become a serious pest of ornamental industry. Environmentally friendly management of HBW is needed and entomopathogenic nematodes are effective biological control agents for managing various insect pests. To develop an efficient management program for HBW, scientists from the University of Florida (Homestead, Florida) and USDA-ARS (Miami, Florida) investigated the efficacy of five commercially available entomopathogenic nematode (EPNs) species to evaluate the control efficiency on HBW. The results showed that EPNs effectively controlled larvae of HBW at different dose rates at both canopy and soil surface level under both laboratory and greenhouse conditions, and EPNs are expected to be important component in developing integrated pest management program for control of HBW in South Florida.

Technical Abstract: The hibiscus bud weevil (HBW) is a pest of tropical hibiscus (Hibiscus rosa-sinensis). Chemical insecticides are currently used for its management, but environmentally friendly alternatives are needed. In laboratory evaluations, five commercially available entomopathogenic nematode species (EPNs) (Heterorhabditis bacteriophora, Steinernema carpocapsae, S. kraussei, S. feltiae, and S. riobrave) were evaluated. Infested flower buds with either first, second, or third instar larvae were treated with a rate of approximately 500 infective juveniles (IJs) per bud. Two EPN species were selected for further evaluation in greenhouse trials due to a high larval mortality (Steinernema carpocapsae and S. feltiae). EPNs, alone or with a fire gel that served as a protectant, were applied to HBW-infested plants using a rate of approximately 500,000 IJ/m2. The effects of foliage-directed applications were also studied in relation to infested fallen buds. There were no effects of the fire gel, but S. carpocapsae showed high HBW larval mortality in both foliage and fallen buds. In a subsequent greenhouse experiment, different rates of S. carpocapsae were tested, including a rate of approximately 428,525 IJ/m2 and 75%, 50%, and 25% of that initial rate. Effects on larval mortality were rate dependent with no difference observed between the full rate and 75% of this rate, making the latter rate a cost-effective alternative. Our study demonstrates that S. carpocapsae can infect developing HBW larvae inside hibiscus flower buds at the canopy and soil surface levels, where fallen infested buds are usually free of control.