A New Tomato Virus in Florida

A NEW TOMATO VIRUS IN FLORIDA

Jane E. Polston Dept. of Plant Pathology Univ. of Florida Plants with symptoms like this were collected in Florida in 2012

Location Date No. Samples Miami-Dade Co. March 15 Lee Co. April 12 These symptoms were similar to those of Groundnut ringspot virus (GRSV) and Tomato spotted wilt virus (TSWV)

Foliage and fruit from a GRSV- infected tomato Foliage and fruit from a TSWV- Photo: courtesy infected Glades Crop Care tomato Detection of Tospoviruses

3 RNA genome segments:

S RNA

M RNA Nucleoprotein coat L RNA We used 3 assays to identify the virus in necrotic plants:

1. ELISA - detects both GRSV and TCSV - detects TSWV

2. PCR - broad spectrum primers that detect many Tospoviruses specific primers for TSWV, GRSV, TCSV 1 2 TCSV TSWV

3. Obtained sequences of the PCR amplified DNA from each genome segment and compared them to published sequences Sequences amplified from necrotic tomatoes were nearly identical to those of Tomato chlorotic spot virus (TCSV)

Percent Nucleotide Sequence Identity Genomic Segment TCSV TCSV GRSV-[LGMTSG] GRSV

S RNA 97% 98% 80% 84% M RNA 98% 98% 99% 94-95% L RNA 98-99% --- 83% ---

Size of PCR fragments: S RNA 1408-1455 nt M RNA 878 nt L RNA 1532 nt Previously, TCSV was only known in Brazil and Argentina

Florida – TCSV is present in Miami-Dade Co. and Lee Co. Known Susceptible Hosts of TCSV

Vegetable Ornamental Weed Hosts Hosts Hosts Common bean Pea Impatiens Amaranthus spp. Cape gooseberry Lilac tasselflower Common purslane Peanut (Physalis peruviana) (Emila sonchifolia) (Portulaca oleracea) Fierce Thornapple Celery Pepper Lisianthus (Datura ferox) Jimson weed Cowpea Potato Petunia (Datura stramonium) Ornamental Lesser swine-cress Escarole Tobacco tobacco (Cornonopus didymus) (Nicotiana glutinosa) Gilo Tomato (Solanum gilo) Lettuce Known Susceptible Hosts of TCSV

Healthy TCSV 1 TCSV 11 TCSV is vectored by several species of thrips Few of the thrips that can be found in Florida crops have been tested for their ability to transmit TCSV Thrips (20 plus spp. not shown) Ability to Transmit Common Name Scientific Name TCSV TSWV Tomato thrips Frankliniella schultzei + + (Common blossom thrips) (dark form) Western flower thrips Frankliniella occidentalis + + Onion thrips Thrips tabaci - + Florida flower thrips Frankliniella bispinosa + Melon thrips Thrips palmi + Red-banded thrips Selenothrips rubrocinctus Tobacco thrips Frankliniella fusca + Chili thrips Scirtothrips dorsalis - Cuban-laurel thrips Gynaikothrips ficorum Flower thrips Frankliniella tritici Gladiolus thrips Thrips simplex Greenhouse thrips Heliothrips haemorrhoidalis Grain thrips Limothrips cerealium Tomato thrips Western flower thrips Frankliniella schultzei Frankliniella occidentalis TCSV is transmitted at different rates by different thrips compared to TSWV Thrips Transmission Efficiency

Scientific Name Common Name TCSV TSWV

Frankliniella schultzei Tomato thrips 37.5% 13.7% (dark form) Frankliniella Western flower 27.6% 66.0% occidentalis thrips

Thrips tabaci Onion thrips 0.0% 9.8%

Frankliniella Common blossom schultzei thrips 5.9% 2.3% (light form) (Tomato thrips) Frankliniella Flower thrips 0.7% 31.8% intonsa TCSV is transmitted at different rates by different thrips compared to TSWV Thrips Transmission Efficiency

Scientific Name Common Name TCSV TSWV

Frankliniella schultzei Tomato thrips 37.5% 13.7% (dark form) Frankliniella Western flower 27.6% 66.0% occidentalis thrips

Thrips tabaci Onion thrips 0.0% 9.8%

Frankliniella Common blossom schultzei thrips 5.9% 2.3% (light form) (Tomato thrips) Frankliniella Flower thrips 0.7% 31.8% intonsa Populations of tomato thrips (F. schultzei) adults in Homestead, FL have increased over the last few years

Mean no. adult tomato thrips per 5 flowers 7 Bean 6 Tomato 5 Pepper Cucumber 4 Squash 3

0 2005 2006 2007 2008 2009 2010 2011

Year Data courtesy of D. Seal Tomato thrips – a vector with a wide host range and the ability to transmit several Tospoviruses Known Hosts: Vegetable Crops: beans (various), eggplant, lettuce, okra, onion, peanut, peppers (various), pigeon pea, pumpkin, spinach, sweet potato, tomato Fiber Crops: cotton Ornamental Crops: carnation, Japanese daisies, rose, thistle, Other Crops: canola, coffee, sorghum, sunflower, tobacco

Dark form of F. schultzei known to transmit: Tomato spotted wilt virus (TSWV) Tomato chlorotic spot virus (TCSV) Groundnut ringspot virus (GRSV) Groundnut bud necrosis virus (GBNV) Chrysanthemum stem necrosis virus (CSNV) Transmission Cycle of TCSV and Tospoviruses

ACQUISITION IS BY IMMATURES TRANSMISSION IS BY ADULTS

CROPS, CROPS, WEEDS WEEDS RECOMMENDATIONS FOR TSWV MANAGEMENT

. Use UV reflective mulches and barriers

. Use TSWV resistant cultivars (SW5 gene) Studies in Brazil have shown that the SW5 gene provides resistance to TCSV

SW5 gene is present in a wide range of cultivars RECOMMENDATIONS FOR TSWV MANAGEMENT

. Use UV reflective mulches and barriers

. Use TSWV resistant cultivars (SW5 gene)

. Use pest management scouting

. Use insecticides for suppression of thrips adults and immatures to reduce within field spread

. Use SAR eliciting compound to reduce symptom appearance

. Use of optimal fertility Summary

. Tomato chlorotic spot virus (TCSV) is now present in Florida

. The most efficient vector of TCSV is the tomato thrips followed by the Western flower thrips

. There is a lot we don’t know about TCSV

. Until we have more specific information, recommendations for management of TSWV are likely to be effective

Sample no 10

A B

Figure 1

TCSV is transmitted by different thrips and at different efficiencies than other tomato-infecting tospoviruses

Thrips Transmission Efficiency

Scientific Name Common Name TCSV TSWV GRSV

Frankliniella Common schultzei blossom thrips 37.5% 13.7% 15.7% (dark form) (Tomato thrips) Frankliniella Western flower 27.6% 66.0% 10.2% occidentalis thrips

Thrips tabaci Onion thrips 0.0% 9.8% 0.0%

Frankliniella Common schultzei blossom thrips 5.9% 2.3% 0.0% (light form) (Tomato thrips) Frankliniella 0.7% 31.8% 0.0% intonsa