Emerging threat: Lysathia ludoviciana (Coleoptera: Chrysomelidae) as a pest of container-grown roses in ornamental nurseries.

Abstract

Lysathia (Altica) ludoviciana (Fall) (Coleoptera: Chrysomelidae: Galerucinae) is a phytophagous insect native to the southern United States and the Caribbean. In the first week of July 2024, adult L. ludoviciana was discovered feeding on Rosa × 'Radtko' ('Double Knock Out' rose [Rose sp.]) in an ornamental container nursery in Georgia (United States); however, its potential impact on other ornamental plants remains unknown. Thus, the objectives of this study were to determine the potential feeding preference and damage characteristics of adult L. ludoviciana on selected ornamental plants, including roses. No-choice assays were conducted where adults were exposed to 11 major ornamental plants. Adult L. ludoviciana fed on Rosa × 'Radtko' and Lagerstroemia hybrid 'GAMAD IX' (crape myrtle). However, Forsythia × intermedia 'Believe It or Not', Weigela florida 'Alexandra', Rhododendron hybrid 'Robled', Hylotelephium 'Pure Joy', Ilex crenata Carl Peter Thunberg 'Compacta', Vaccinium corymbosum L. 'Blue Suede', Distylium 'Cast in Bronze', Hibiscus syriacus L. 'Lavender Chiffon', and Hydrangea paniculata Siebold 'Limelight' plants were not consumed. In a choice assay, adult L. ludoviciana only fed on roses over crape myrtle. Systena frontalis (F.) (Coleoptera: Chrysomelidae) is a serious pest on various ornamental plants. When both adult L. ludoviciana and S. frontalis were tested in a combined choice assay, L. ludoviciana only consumed roses, whereas S. frontalis consumed the rose and crape myrtle. Adult L. ludoviciana consumed leaf tissue from the edge, whereas adult S. frontalis initially scraped and consumed the epidermal tissue. Thus, L. ludoviciana could develop into a major pest on roses if not managed.