The US League of Tea Growers received a request from Dr. Childers, University of Florida, to participate in a study on mite varieties present in US grown tea. We are inviting each of you to take the time to read his letter to our members and get involved in his study! Dr. Childers’ email address is at the end of the article and we encourage you to ask questions and get involved. The benefits from a study like this are exactly why this league was formed and we look forward to reading Dr. Childers’ findings.
January 26, 2015
I am a retired professor formerly with the University of Florida at the Citrus Research and Education Center in Lake Alfred. You can find me on their web site, locate emeritus/retired faculty and scroll down. You can also find me on Google…Carl C. Childers, University of Florida. I conducted research on citrus with emphasis on controlling mite pests. One area was evaluating potential biological control agents (primarily predacious mites).
Some years ago I saw the article in Southern Living Magazine about a tea farm on Wadmalaw Island in South Carolina. It was a partnership at the time and their brand of tea was American Classic. They stated in the article that pesticides were not used. I immediately became interested as tea is known to have a large number of mite pests as does citrus. I met with the partners and began taking samples to look for mites. Since then I’ve taken samples in a number of locations in and around Charleston, South Carolina, Alabama and Mississippi.
The more I looked into the literature the more I realized that there was very little useful information regarding control of pest mites without having to resort to the use of acaricides = miticides. Much of the published literature is from India and much of that is of limited use. There have been some excellent studies in places like Indonesia but nothing here in the States. I’ve talked with colleagues and we have decided to do a book on tea mites that would include pest mite species, predacious mites with focus on mite predators, and possibly include other mite groups that contribute to organic breakdown of tea plants or mites that feed on organic debris on plant surfaces. The work would cover tea mite pests worldwide as well as what is found here in the States. So far, I’ve found 8 to 10 plant feeding mites that could become potential pests of tea here in the States. The good news is that all but one species occur in low numbers most likely due to predation by a diverse group of predatory mites.
It would benefit a young, developing industry to know about these mites early on rather than discovering unexpected plant damage in the future. Part of our team consists of two South African scientists. They are both taxonomists and provide excellent support in species identifications of tea mites collected here in the States. They will begin sampling for mites on tea in various plantations in South Africa as well as from a second African country this year. Several countries in Africa are actively involved in growing tea
My sampling consists of collecting leaves, fruit (=seed pods), and three ages of wood at each location. Each of these samples is collected separately (i.e., 50 leaves, or 25 fruit or 30 cm of wood per age of the wood. I look at one, two and three plus year old wood cuttings. Each sample is immediately washed in a bucket containing 80% ethanol. Where possible I take repeated samples (usually three per sample type). Each sample is vigorously agitated in the alcohol and plant material is then discarded. I pour the rinsate (with the mites) into a labeled glass jar and return it for processing. No plant materials leave the farm!
Mites range in size from less than 100 micrometers to 1 mm in length….very tiny. Many of these mites require a magnified handlens to even see them! However, if certain pest mite numbers are great enough then there is potential for visible plant damage to be seen.
I would like to request that you contact your membership to see if additional tea growers (farms and nurseries) would be willing to let me sample for mites. There are no fees or expected payment by me. I see this as a needed opportunity to expand our knowledge of the mite complex on tea in the States and to potentially contribute to the growth of a new industry. Ideally, sample sites of several acres would be preferred to small plots of tea. My objective, hopefully, is to locate farms/nurseries in different states to gain a broader idea of mite diversity and potential problems facing a young industry.
Thank you for your consideration.
Carl C. Childers, Emeritus Professor of Entomology, University of Florida
e-mail address: firstname.lastname@example.org