The Asian shrub Rhodomyrtus tomentosa (Aiton) Hasskarl (Myrtaceae) is an invasive weed in Florida and Hawaii, U.S.A. Surveys for natural enemies of this exotic shrub in Hong Kong, China resulted in the development of a laboratory colony and host range testing of Neostauropus alternus (Walker, 1855) as a potential biological control agent of R. tomentosa. Twelve critical test plant species were presented to larvae of N. alternus. Complete development was limited to R. tomentosa, the ornamentally important Myrtus communis Linneaus (Myrtaceae), and the Florida natives Myrcianthes fragrans (Small) (K.A. Wilson) (Myrtaceae) and Morella cerifera (Linneaus) Small (Myricaceae). Total development time was more than ten days faster with R. tomentosa versus M. communis and M. cerifera, with the latter species requiring an extra larval instar to reach the pupal stage. Consumption rates were similar among R. tomentosa and M. cerifera, but due to the longer development time, larvae consumed two-fold more leaf material on M. cerifera. Despite an apparent larval survival and development preference for R. tomentosa, it is clear that the physiological host range of N. alternus includes M. cerifera and M. communis. The generalized feeding patterns exhibited in this research indicate that additional resources dedicated to the development of N. alternus as a biological control agent of R. tomentosa in Florida are unwarranted.