Biological control of poinsettia thrips, Echinothrips americanus (Thysanoptera: Thripidae), on lima bean using the ghost ant, Tapinoma melanocephalum (Hymenoptera: Formicidae)

Authors: PARK, YOUNG-GYUN - University Of Florida; HOUBEN, KATHERINE - University Of Florida; McKenzie, Cindy; OSBORNE, LANCE - University Of Florida

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2025
Publication Date: 1/22/2026
Citation: Park, Y., Houben, K., Mckenzie, C.L., Osborne, L.S. Biological control of poinsettia thrips, Echinothrips americanus (Thysanoptera: Thripidae), on lima bean using the ghost ant, Tapinoma melanocephalum (Hymenoptera: Formicidae). Florida Entomologist. 109(1):20250019. 2026. https://doi.org/10.1515/flaent-2025-0019.
DOI: https://doi.org/10.1515/flaent-2025-0019

Interpretive Summary: The poinsettia thrips, Echinothrips americanus Morgan (Thysanoptera: Thripidae), is a polyphagous agricultural pest that can utilize 106 plant species across 48 families as hosts by primarily feeding on plant leaves, causing light spots that reduce photosynthetic efficiency and inhibit plant growth, leading to crop damage. Predatory mites and thrips have been shown to suppress this pest in greenhouses, but management still largely depends on chemical control. In this study, we evaluated the potential of the ghost ant (Tapinoma melanocephalum), a small species commonly found in Florida, as a biological control agent against poinsettia thrips under controlled greenhouse conditions. Ghost ants significantly reduced the density of poinsettia thrips on lima bean plants. Furthermore, ghost ants also appeared to suppress two spotted spider mites when both pests were present. Depending on the pest composition of a given system, ghost ant populations occurring naturally around cropping areas may be utilized as a component of pest management, and the development of supporting research and control programs is recommended.

Technical Abstract: Echinothrips americanus is a polyphagous pest of increasing concern in agricultural crop production due to its broad host range and rapid population buildup. In this study, we evaluated the potential of the ghost ant (Tapinoma melanocephalum), a small species commonly found in Florida, as a biological control agent against E. americanus under controlled greenhouse conditions. To assess ant-mediated suppression, lima bean plants were artificially infested with E. americanus and assigned to either ant-allowed or ant-blocked treatments. Ant-blocking was achieved using a physical barrier system involving soapy water to prevent access by T. melanocephalum. The experiment was replicated four times, with weekly observations conducted over a three-week period. Key response variables included ant presence rate, thrips density, and spider mite (Tetranychus urticae) infestation rate. Results demonstrated a clear suppression effect: thrips densities were significantly lower in the ant-allowed treatment across all trials, with a final mean of 6.9 thrips per plant compared to 475.3 in the ant-blocked treatment. Similarly, spider mite infestations were significantly reduced in the presence of ants. These findings highlight the potential of T. melanocephalum as a low-input biological control agent in greenhouse systems, particularly for the simultaneous suppression of E. americanus and co-occurring T. urticae. Future studies should explore its integration into existing pest management strategies.