Written by Phil Cerroni
Most days Sheila McBride arrives at work to find sick plants scattered about. She loves that.
“People come in to find out what is wrong with their plants, and we help them out,” said McBride, diagnostician at the Texas Plant Disease Diagnostic Lab in College Station.
The lab, part of the Texas A&M AgriLife Extension Service, handles up to 2,000 samples a year, according to Dr. Kevin Ong, director.
“This plant clinic started off in 1956 solely to support county AgriLife Extension agents in helping farmers, but over the years that has changed,” Ong said. “We still use the Extension mission to serve the people of Texas, but we now have a big group of samples that come in from the growers and professional landscapers, arborists and homeowners.”
For McBride, the daily challenge comes from opening boxes from mail services or accepting samples in person, then carefully examining the leaves, stems, branches and roots to determine why a plant is sick.
“I have to look at each sample and decide in my diagnostic mind how I am going to treat it,” she said. “My number one best friend is my microscope. Probably about 80 percent of the plants that come in I can diagnose using my microscope. There are specialized spores that I can see … and that will lead me to find out what’s causing the problem.”
And the most typical sample the lab receives? Turfgrass from homeowners wanting to correct problems in their yards.
The plant clinic uses a variety of other methods to diagnose problems if the source isn’t determined under the microscope, she said. Sometimes plant samples are put in a specialized medium to see what grows. Other times a polymerase chain reaction is used to look for organisms that cannot be observed by microscope.
McBride said she also likes to educate people about plant diseases and provide tips and advice about curing or preventing illnesses in plants.
Information on how to get a diagnosis for a sick plant can be found at http://plantclinic.tamu.edu/.
McBride offers these tips for sending samples.
If possible, send a whole plant. “I like to see the leaves, the stems, the roots, the whole picture,” she said. “In fact, send pictures as well, if you can,” McBride said.
Trees obviously can’t be shipped intact, but send more than a leaf. A branch would be good. “Individuals see that a leaf turns yellow and so they just send us a leaf,” she said. “But we need more than that to get the full picture.”
Don’t add water to the sample or make it wetter than it already is.
Send samples fresh. “Don’t let a sample sit in a vehicle for four days in 100 degree weather,” she said.
Among her favorite diagnoses is “fire fungus” after the Bastrop fires in 2011 and a palm tree disease that appeared for the first time in Texas.
“After the fires, people started seeing an orange fungus growing all over the trees,” McBride said. “The people around Bastrop were worried that it would be harmful to humans, their pets or the wildlife.”
She said the lab performed a series of tests – from isolating and growing the fungi to DNA analysis and classical morphological identification to determine it was a harmless Pezizomycete – similar to some fungi that appeared after the 1980 eruption of Mount St. Helens.
The palm tree disease, she said, was identified in the lab and now is being confirmed by attempting to infect healthy baby palm trees growing in the lab in order to watch the disease progression and prove it is killing palms.
The plant clinic tries to provide for each sample not only a diagnosis but some recommendations for control.
“And I also try to give them just a little bit of information as far as the actual pathogen and what it does,” she said.
The cost for the diagnosis and recommendations is $35 for in-state samples or $55 for samples from outside of Texas.
“The interaction we have with plant owners gives us the opportunity to provide them with information and teach them how to take care of plants,” Ong added. “If a disease problem is caught early, then action may be taken to prevent further loss and in fact save quite a bit of money. Also we benefit from healthier plants or even a readily, available food supply.”
Source: Texas A&M University System