Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2007
Publication Date: 1/1/2008
Citation: Paini, D.R., Funderburk, J.E., Jackson, C.T., Reitz, S.R. 2008. Reproduction of four thrips species (Thysanoptera: Thripidae) on uncultivated hosts. Journal of Entomological Science. 42:610:615. Interpretive Summary: Thrips are key pests of vegetable crops in the southern USA because of the ability of some species to transmit plant viruses. The thrips that infest crops are primarily migrants that enter crop fields from outside sources. Therefore an understanding of thrips ecology outside crops is needed to develop new IPM strategies. Scientists from the Center for Medical, Agricultural and Veterinary Entomology and the University of Florida conducted systematic surveys of uncultivated plants near agricultural fields to determine which plant species serve as reproductive hosts for four pest thrips species, Frankliniella occidentalis, F. bispinosa, F. tritici, and F. fusca, and the relative abundance of these plant species over time. Both native and non-native plant species from 15 plant families were identified as reproductive hosts. Two reproductive hosts, cutleaf evening primrose and Italian rye grass, were identified as important sources of these thrips, as they were abundant in our sites, have a widespread distribution throughout the US, are hosts of TSWV, and are utilized during the spring when thrips populations are increasing and beginning to invade commercial crops. All four thrips species tend to occur on hosts when the plants are flowering. The results of this study provide a key step in identifying those plant hosts that are of most importance to Frankliniella thrips population dynamics and the characteristics that distinguish their reproductive hosts from other non-host plants.
Technical Abstract: Many researchers have focused on the population dynamics of thrips within crops. However, thrips often migrate into crop from outside sources. An understanding of thrips ecology outside crops is needed to understand thrips ecology and subsequently develop strategies that limit damage to crops both from thrips feeding and Tomato spotted wilt virus infection. We surveyed uncultivated plants in an agricultural setting for one year recording the presence of larvae and adults of Frankliniella occidentalis (Pergande), F. bispinosa (Morgan), F. tritici (Fitch), and F. fusca (Hinds). Reproductive hosts were identified as those plant species in which larvae were found, whereas feeding hosts were identified as those plant species in which only adults were found. Both native and non-native plant species from 15 plant families were identified as reproductive hosts. Two reproductive hosts, Oenothera laciniata Hill and Lolium perenne multiflorum (Lam.), were identified as potentially important contributors to thrips population dynamics as they were common in our sites, have a widespread distribution throughout mainland US, are hosts of TSWV, and were utilized during the spring when thrips populations are increasing and beginning to invade commercial crops. Generally, all four thrips species utilized feeding hosts and reproductive hosts when they were flowering and this may be a result of the availability of pollen (host nutrition) and/or enemy free space. These two factors may also contribute to distinguishing reproductive hosts from non-reproductive hosts.