The Role of Temperature and Precipitation on Thrips Populations in Relation to the Epidemiology of Tomato Spotted Wilt Virus.
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2008-11-09
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MORSELLO, SHANNON CATHLEEN. The Role of Temperature and Precipitation on Thrips Populations in Relation to the Epidemiology of Tomato Spotted Wilt Virus. (Under the direction of George G. Kennedy.)
The influence of temperature and precipitation on spread of Tomato spotted wilt virus (family Bunyaviridae, genus Tospovirus, TSWV) in chickweed (Stellaria media), population growth of its? primary vector, Frankliniella fusca (Hinds), on chickweed, and the timing and magnitude of F. fusca and Thrips tabaci Lindeman dispersal from winter hosts was characterized using population data collected during spring 2004, 2005 and 2006, and trapping data from North Carolina and Virginia from 1997 ? 2001 and 2004 ? 2007. Frankliniella fusca populations on chickweed were suppressed immediately following rain events, but precipitation occurring in early May delayed senescence of chickweed and ultimately resulted in higher populations by the end of May. Spread of TSWV within chickweed plots was directly related to the size of the immature F. fusca population in the plot. Regression analysis determined that temperature, total precipitation and number of days with precipitation during January through May explained 70% and 55% of the total variation in the numbers of F. fusca and 57% and 63% of T. tabaci, respectively captured from 1 April ? 10 May and 1 April ? 31 May. Further analysis determined that temperature measured throughout the overwintering period positively influenced the number of dispersing F. fusca throughout Spring, and precipitation that occurred during late March, late April, early May and late May influenced the dispersal of F. fusca by killing immature larvae, suppressing adult flight or delaying senescence of host plants. Additional models explained 60%, 74%, 68% and 69% of the variation in the number of dispersing F. fusca captured during 1 ? 15 April, 16 ? 30 April, 1 ? 15 May and 16 ? 31 May, respectively. Validation resulted in weak correlations of observed and expected values for each trapping interval, but similar trends over time. Future work developing risk models for thrips flights and TSWV on an area-wide basis must be species specific and include additional parameters to better capture late-season host plant dynamics.
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tobacco thrips, thrips dispersal, Epidemiology
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Degree
PhD
Discipline
Entomology
