Grower Call To Action: Chilli Thrips and Tea Scales

ThripsDr. Chen, of LSU, in conjunction with other university professionals, is leading a USDA pest management alternative program on thrips and has approached because our tea growing members could be very helpful by providing samples. Members sending samples will be kept anonymous and data will be summarized by general geographic regions – several states will be grouped in a region so specific locations of the pests will not be disclosed. Timeline wise, now is a good time to observe these pests. Dr. Chen’s letter is below:

Dear Members of the US League of Tea Growers,

I work at the LSU AgCenter Hammond Research Station as an Associate Professor, and my research focuses on nursery and landscape plants. You can find my author page here:

I work closely with the Green Industry in Louisiana with a focus on plant nutrient/irrigation management and their interactions with pest outbreak and management. My experience with chilli thrips and tea scales come from IR-4 projects (efficacy trials with new chemical classes on thrips and scales) and leading two USDA NIFA projects on western flower thrips and chilli thrips, and co-PI on a TAMU project managing crape myrtle bark scale. These projects emphasize the development of a forecasting model using degree-days and plant-pest phenology for early detection of outbreaks and alternative controls including biopesticides that are low impact on natural predators and pollinators.

At the research station, we started collecting tea cultivars in fall 2014 for a tea evaluation garden. I have noticed several insect and mite problems from plants collected and under our growing conditions at the research station. Last week we received tea plants from a friend out of state that were hosting a large number of chilli thrips and tea scales on them. These are the two key pests in tea fields in China and India, where chilli thrips is aka yellow tea thrips.

In 2003, Hawaii developed a pest and disease guideline. However, there is no documentation of key pests in the continental US. It is apparent to me that this is good timing to document geographic distribution of pests in current tea growing areas, which can be used for developing a more strategic approach for pest management and providing reference for research directions and funding supports.

I hope no one is having pest problems but we need to be proactive or at least reactive to potential pest problems. It takes years for research to be fruitful and it’s never too early to think about research directions with known enemies. I would like to ask for samples from our supportive tea growers, collectors, and enthusiasts. Data will be used in a general matter and no names of any growers or locations will be mentioned or related to any pests reported.

We will start with chilli thrips and tea scale because they are known key tea pests in tea growing countries and are established in the southeastern US. Tea scale can be found in magnolia, camellia, sasanqua, gardenia, and several other garden plants and trees. Chilli thrips, Scirtothrips dorsalis (Hood) was first found in 2003 and has since established with a wide range of host plants: vegetables, roses, indian hawthorn, cleyera, etc. See article about this thrips here: Chilli thrips injures young leaves and the tip of the shoots, and the damaged leaves are deformed in shape, become thicker, with scars on the back assembling herbicide burns (see photo above). The thrips themselves are tiny and better to be identified under a microscope.

The tea scale, Fiorinia theae (Green) is a common scale on many shrubs especially camellias. Symptom and damage on tea is similar to camellia, yellow spots (stippling) seen on upper leaves and small but visible scales on the lower leaf surface.    

Members – please check your tea plants for similar symptoms and if you find anything suspicious, send me a sample. (1) Put a paper towel that is moist but not wet into a Ziploc bag, (2) clip off a stem about 3 to 4 inches long with at least 3 leaves, and with the tip if chilli thrips are suspected, and place it in the bag and seal with some air in the bag, and (3) mail it to me using Priority Mail small box at the address below. Please leave your name, address, and phone number with the sample in case we need to contact you. The small box will ensure the sample not be smashed during shipping. Upon receiving the samples, we will rinse the leaves and the bag with 60% ethanol solution and filter for thrips and scale crawlers. Most samples will be discarded after identification but some will be mounted for later reference.

Members are welcome to send in any other pest samples and we will get them identified as quick as possible and will call you to discuss the need for control. Very often, problems will come and go, and it’s only when conditions favor for an outbreak that control measures are needed. Precautions can be made to reduce chances of an outbreak. For example, if you have camellias/sasanquas in vicinity, you may want to check them for tea scales and treat early before they develop high numbers and start to move into tea plants.

My shipping address and phone number are below. Please contact me with any questions as I’d be more than happy to discuss this project and any other pest management topics with you.

Thank you!


Address: Dr. Yan Chen

LSU AgCenter Hammond Research Staiton

21549 Old Covington Hwy,

Hammond, LA 70403

Phone: 985.543.4125 or 985.543.4378



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