The Difference Between Promoting Proper Plant Health Care and a Misdiagnosis

The Difference Between Promoting Proper Plant Health Care and a Misdiagnosis

Diagnosis is an important step in discovering which tree and plant pests, diseases and other problems are affecting your landscape’s health and beauty. So, what makes a plant material sample good and helpful vs. not-so-helpful?

Davey’s Debbie Miller, senior diagnostician and plant pathologist at the Davey Institute, discusses what she looks for in a good plant sample. Here are Miller’s 7 Steps to Collecting a Good Tree Sample:

Step 1: Contact an Arborist for Help. If you see shrub or tree leaf spots or discoloration, bark splitting, or other signs of disease and insect infestation, contact your local professionally trained arborist to investigate your plant. The arborist will either diagnose the problem on the spot or send in a proper sample to the lab for further tests and treatment options.

Step 2: Collect Multiple Samples. Miller says, the number one problem with samples is an insufficient sample. For example, it is difficult to diagnose the problem of an 80 foot oak tree with only 3 or 4 leaves. In order to properly diagnose a tree problem, examine tree branches, leaves, insects and fungus, you need multiple branches with leaves, insects or fungal reproductive structures in order to determine the agent—not just one twig or leaf.

Helpful Tips for Tree Samples:

  • Tree branches should be at least 6 to 8 inches long for a correct sample.
  • Leaf samples should include branch and stems.
  • Mushrooms should include caps and stems.
  • Insect samples require more than one specimen.
“mushroom

Step 3: Select Samples Showing a Progression of Symptoms. Speaking of multiple samples, it’s very important to send in various stages of the infestation or disease on leaves or twigs. Miller suggests collecting samples showing severe, moderate and light symptoms, in order to get a better diagnosis. A healthy control (untouched by disease or infestation) is also important for a true assessment. Dead branches and leaves may be helpful for detecting some problems as long as you provide other living samples as well.

Step 4: Properly Package Samples for the Lab. Samples must be packaged following the United States Department of Agriculture (USDA) federal rules and regulations. When sending a sample, make sure to double bag it using sturdy Ziploc® or garbage bags, depending on the size of the sample. Make sure the bags are completely sealed. If you are sending a fungal specimen, wrap it in a dry paper towel in order to keep it from becoming injured during shipping.

Step 5: Photos Help the Process. Clear, high-definition photos of symptomatic trees or plants help the diagnostic process—providing scientists a clear image of what the infection or disease looks like at the site.

Step 6: Send in Samples Early in the Week. It helps to send samples on Monday through Wednesday, so that samples don’t spend the entire weekend in the truck or warehouse. It’s important to test samples while they are fresh and before samples become degraded.                   

Step 7: Your Results. After all the previous steps have been taken, local scientists will examine the sample and create a list of solutions that the client will receive based on the diagnosis. Your local arborist may explain treatment options in order to combat disease or infestation and create lasting solutions for your landscape.

“Remember: The quality of the diagnosis is dependent on the quality of the sample,” Miller says.

If you think one of your trees or plants need to be tested for disease, contact your local, professionally trained Davey arborist for a free consultation.

Add a comment:
Featured or Related Blog Posts
  • A Matter of Life & Death

    The first time I really noticed, it was a week before Mother's Day.

    Every year we invite the moms over for a brunch of crepes, fruit salad and mimosas. We were hoping for decent weather to enjoy the festivities out on the patio, so we were cleaning up the yard in preparation. We snagged those early weeds that sprouted, spread some new mulch in our flower beds and prepped our vegetable garden, including planting green beans, spinach and sugar snap pea seeds with the kids.

    By then, most of our trees had stretched and opened their leaves. In the front, the red maples and the oaks were full of green leaves, and the weeping cherries and crabapples were in bloom with white and pink flowers. The 'Cleveland' pears that line the street were also showing their tiny white blossoms.

    Read More
  • Under Our Umbrella

    Just the other day, I was attending a professional dinner meeting, so I traded my usual work clothes and boots for a simple dress and heels. And just as I arrived at the restaurant, it started to rain … and I don't mean just pitter-patter, pitter-patter. It was the start of what was soon to be a great, big thunderstorm. I stepped out of my car and prepared to run for it, and, wouldn't you know, my first step was into a giant puddle. Needless to say, I was squishing around in my heels with soggy toes for the rest of the night. 

    The latest wet weather has left many wringing out their wet socks in search of higher and drier land. It's not a good feeling to be constantly wet - so wet you feel you'll never get dry. If you're in one of these regions with above average rainfall right now, you know this feeling. Now imagine how your trees must feel.

    Constant rain, storms and flood watches have us all protecting our socks with good shoes, strategically avoiding puddles and cleaning our gutters so our homes and toes stay dry. But what about our plants and trees? Those poor perennials and conifers, particularly those placed in low areas, are left to tough it out, stuck in the muck. Driving through my neighborhood, I've seen more than one tree surrounded by a large puddle of water that looks like it's not draining anytime soon.

    Read More
  • Pittsburgh Bridges Urban Forestry Connections at Partners in Community Forestry Conference

    Trees matter. From eliminating air pollution to protecting our sensitive ears from the noise pollution our busy, working lives create, trees benefit urban environments in several ways. But tree care providers and their communities must realize the efforts involved to sustain our invaluable forests for the benefit of future generations-now and looking ahead in the future.

    That's where Davey and our fellow urban forest supporters step in.

    This week, attendees, exhibitors and presenters from Davey Resource Group and the Davey Institute joined several organizations in Pittsburgh, Pa., for the Partners in Community Forestry Conference, organized by Arbor Day Foundation.

    Read More
  • Davey Institute Hosts Tree Biomechanics Research Week Symposium

    Tree limbs drop from bucket truck lifts and cranes as researchers make observations, form calculations and answer questions below.

    While an individual depletes the foliage of a fallen branch by removing its leaves one-by-one, another researcher trims all limbs from the trunk of a tree to test its durability and strength without them.

    The branch of a tree receives a coat of paint before camera software begins analyzing the compression in the bark upon branch movement. 

    Read More
  • Are Japanese Beetles Doing Damage to Your Tree Leaves?

    As the summer heat hits, we take special care to maintain our trees.

    Unfortunately, Japanese beetles give our trees just as much attention, but don't treat them as kindly. 

    Below discover what trees Japanese beetles do and don’t like to eat and how to get rid of this garden pest.  

    Read More

Request a consultation

What do you need services for?
Sorry, we can’t seem to find the zip code you specified. Our residential tree care offices may not service your area. If you believe this is an error, please try again. Need help? Email us at info@davey.com.
  • Email newsletter
  • Woodchips
*Please fill out all required fields.