First report on voracity and feeding preference of predatory beetle, Thalassa montezumae (Coleoptera: Coccinellidae) on croton scale, Phalacrococcus howertoni (Hemiptera: Coccidae)

Authors: FRANCIS, NETALIE - Florida A & M University; KANGA, LAMBERT - Florida A & M University; MANNION, CATHERINE - University Of Florida; HASEEB, MUHAMMAD - Florida A & M University; ANANGA, ANTHONY - Florida A & M University; Legaspi, Jesusa

Submitted to: Agriculture Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2022
Publication Date: 7/9/2022
Citation: Francis, N., Kanga, L.H., Mannion, C., Haseeb, M., Ananga, A., Legaspi, J.C. 2022. First report on voracity and feeding preference of predatory beetle, Thalassa montezumae (Coleoptera: Coccinellidae) on croton scale, Phalacrococcus howertoni (Hemiptera: Coccidae). Agriculture Journal. 12(7). https://doi.org/10.3390/agriculture12070990.
DOI: https://doi.org/10.3390/agriculture12070990

Interpretive Summary: The croton scale was first discovered in south Florida in 2008 as a new species in a new genus. The scale is a serious pest in south Florida landscapes where crotons are abundant in nursery production. The scale is particularly destructive because of its high reproductive rate and production of sooty mold. Scientists from USDA, Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology in Tallahassee, FL, in collaboration with researchers from Florida A&M University and University of Florida tested the predatory beetle Thalassa montezumae as a biological control agent. To our knowledge, this study is the first to evaluate this beetle against this new pest. We found that each beetle ate about 157 scale nymphs. Most scales eaten were in their second nymphal stage. Female predatory beetles appeared to prefer faster prey than their male counterparts and used less energy in searching for food. However, no differences were found in prey first visited when offered prey of different stages. Percentage of egg hatch was similar for both sexes. In cropping systems where croton scale has become an economic pest, Thalassa montezumae should be considered as a biological control agent within a biologically-based integrated pest management program.

Technical Abstract: The croton scale (CS), Phalacrococcus howertoni Hodges & Hodgson gen. nov., sp. nov. (Hemiptera: Coccidae), (new genus and species) was first found in the United States in Florida. The scale can become a pest because of its high reproductive rate and production of sooty mold. Here we evaluated predation potential by the predatory beetle, Thalassa montezumae Mulsant (Coleoptera: Coccinellidae) as a biological control agent. To our knowledge, this is the first study of predation by T. montezumae on the CS. Mean predation by adult T. montezumae was measured at 157 of all stages of P. howertoni. Broken down by prey life stage, mean consumption by adult T. montezumae was highest on 2nd stage nymphs followed by 3rd stage nymphs, and adult P. howertoni. There was no significant difference between male and female adult T. montezumae in the prey first visited when offered a choice of 2nd or 3rd instar nymphs, or adults of P. howertoni. Thus, the levels of acceptance did not vary significantly between stages of prey visited by the males and females. In a study of predation patterns, females chose prey faster than males and appeared to use less energy to search for food. There were no significant differences in egg hatch due to female prey diet of 2nd or 3rd stage nymphs or adult croton scales. Should P. howertoni become a pest, T. montezumae should be considered as a biological control agent within a biologically-based integrated pest management program.