Euphorbia punicea (Euphorbiaceae), commonly known as Jamaican poinsettia, is an evergreen shrub with dark green leaves and flashy red bracts. Bracts are sharply contrasted by rosettes of dark green leaves and can be observed in early summer, spring, fall, and winter. This shrub, native to Jamaica, is suitable in southern climates both in the landscape and as a seasonal patio container plant. Outdoors, the plants can reach as high as 5 meters. In January of 2012, E. punicea plants growing in an ornamental nursery in Dade Co., Florida, were observed with stunted growth and yellowing leaves. Root systems of affected plants were collected and sent to the Florida Department of Agriculture and Consumer Services, Nematology Laboratory, Gainesville, FL. Root systems showing symptoms of root-knot nematode infections were heavily galled and had already started rotting. Galls were observed in the primary, secondary, and tertiary roots. Species identification was initially performed using morphology and morphometrics. The morphology of the perineal patterns and measurements of selected characters of the second-stage juveniles fit those of the original description for M. enterolobii (3). The nematode species identification was confirmed using PCR to amplify mtDNA with the C2F3/1108 primer set (1) and a species-specific SCAR primer set, MK7-F/MK7-R (2). The PCR products were approximately 700 bp for mtDNA and approximately 520 bp for the SCAR, which were identical to those previously reported for M. enterolobii (1, 2). Sanitation practices should be implemented to avoid the spread of this nematode species within and between ornamental nurseries. Planting material should be produced in media free of this pathogen to avoid its introduction into uninfested nurseries and landscape areas. M. enterolobii has a wide host range, including cover and vegetable crops, fruit trees, herbs, and ornamental and weed plants. To our knowledge, this is the first report worldwide of E. punicea as a host of M. enterolobii.
References: (1) T. O. Powers et al. J. Nematol. 37:226, 2005. (2) M. S. Tigano et al. Plant Pathol. 59:1054, 2010. (3) B. Yang and J. D. Eisenback. J. Nematol. 15:381, 1983.