Current Projects
in TVAC Lab

Tomato Spotted Wilt Virus: Thrips Identification

Pre-season Risk Assessment of Thrips Vectors of Tomato Spotted Wilt Virus in Solanaceous Crops

Introduction
Methods
Project Results

Introduction:

Tomato spotted wilt virus (TSWV) is an important plant virus which causes severe economic losses in several crops in the southeastern U.S. The disease is vectored by three species of thrips in Georgia: Frankliniella fusca, F. occidentalis, and Thrips tabaci. Annual losses due to the disease and the control of the thrips vectors exceeds $100 million in crops such as tomato, pepper, and tobacco.

The purpose of this project is to provide growers with a better tool with which to plan for the growing season. Data provided by this research will provide information on the possible risk of TSWV for the upcoming season. This will allow the grower to decide which options may be appropriate for the season. A low risk year will allow the grower to choose black instead of reflective plastic which could save $150 per acre. A high risk year may suggest reflective plastic and resistant plants.

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Methods:

Monthly sampling to determine the presence of thrips populations surrounding and within two fields are conducted in Brooks, Colquitt, Decatur, and Tift counties, GA.

Method 1. Six sticky traps are placed along a transect outside the field and six parallet traps are run within the field. The outside traps serve as the center point of plots for weed collection. Each of the sticky traps consists of one yellow card and one blue card stapled to opposite sides of a 12" garden stake. The traps are left in the field for one week before returning them to the lab for counting.

Method 2. Sampling for TSWV in weeds consists of harvesting host weeds in six plots adjacent to each production field. Florida pusley, purslane, morning glory, beggarweed, wild radish, and spiny sowthistle are targeted during the summer/fall season and chickweed, cudweed, sowthistle, Virginia pepperweed, swinecress, and Carolina geranium during the winter/spring season. Samples of each of the weeds present are collected and sent to the Virology Lab on the Tifton campus for ELISA to determine the level of TSWV infection.

Samples from the weeds are collected in gallon ziplock bags and returned to the lab. The weeds are placed in Berlese funnels for three days which desiccate the weeds and force the thrips into alcohol vials. Thrips are counted and sorted into appropriate categories.
Crop leaf samples are taken during the growing season to estimate the percentage of TSWV in the fields. One leaf sample is selected from the top 1/3 of 90 randomly chosen plants in the field. These samples are sent to the Virology Lab for analysis using ELISA.

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Current Project Results:

You will need Adobe Acrobat Reader to download or open the PDF files on this page.

Monthly table of TSWV and thrips in each field

2004

2005

2006