Host Associations of Thysanoptera with Paspalum distichum and Paspalum notatum (Poales: Poaceae)

The western flower thrips, Frankliniella occidentalis (Pergande); flower thrips, Frankliniella tritici (Fitch); and tobacco thrips, Frankliniella fusca (Hinds), are abundant, polyphagous species in the southern United States. Paspalum notatum Flugge and Paspalum distichum L. (Poales: Poaceae) are low-maintenance, warm-climate, tolerant grasses that are used for pasture and residential lawns and along roadsides. The potential of P. notatum and P. distichum to serve as sources of the common polyphagous Frankliniella thrips in the southeastern United States was evaluated. The abilities of F. fusca, F. occidentalis, and F. tritici to survive and reproduce on vegetative-stage P. distichum, P. notatum ‘Argentine’, P. notatum ‘Pensacola’, and P. notatum ‘Tifton 9’ were compared in laboratory no-choice tests. Survival of the adults of each thrips species was ≈20% after 12 d on each of the Paspalum treatments. No progeny were produced by F. occidentalis on the U.S. native P. distichum, and the other thrips species produced very few progeny on this host. The number of progeny of each thrips was very low on all P. notatum cultivars. A field survey of the Thysanoptera associated with P. notatum Argentine also was conducted to determine whether the Frankliniella thrips were feeding or reproducing under field conditions. A few male and female adults of F. tritici and F. fusca were noted in the racemes, but larval populations were not observed. Reproducing populations of Caprithrips insularis Beshear and Haplothrips graminis Hood were present in the stems and leaves, and the racemes, respectively. Collectively, the laboratory and field studies revealed that the tested P. notatum cultivars and P. distichum accession are poor hosts for reproduction of the Frankliniella thrips in the southern United States and that the large plantings of these grasses are not serving as sources of pest Frankliniella thrips.