AGNET - The Palm Tree Whodunnit, Part 2
By Laurie Sheldon
Based loosely on Robert Northrop's presentation at the 2012 FNPS Conference. (If you missed Part 1, click here.)
Monday, December 11, 2006, 59°
I had just arrived at headquarters when I got a call from the lab Shannon and I sent tissue samples to the week before. Phil Shannon’s my partner at the Department of Agriculture’s Plant Industry Division. Our boss is Captain Crunch. My name is Sunday - Moe Sunday - I carry a badge.
I phoned Shannon to give him the news. “Hey - where are you?” He responded, “well, seeing as that you called my home phone number and I answered, where do you think I am?” “Oh, right,” I answered sheepishly, “my bad. You’ve got to come in PRONTO. I have news that you just won’t believe.” “Can’t I wait to not believe it for another few hours?” I quickly barked “NO,” then hung up so he couldn’t argue.
|Mr. Curt Meanie, the host with the most.|
“Hello? Is this Mr. Meanie?” A gruff voice on the other end of the line replied, “depends who’s axing.” Shannon sweetly followed, “Hello, sir. This is Phil Shannon from the Department of Agriculture’s Plant Industry Division. We took a sample from your date palm a few weeks ago and just got the results back. Apparently, your tree has the first case of Texas Phoenix Palm Decline (TPPD) in Florida. It’s caused by a phytoplasma, which is basically a bacterium without a cell wall.” Meanie answered, “well how in the devil did it get into my tree? I don’t even know anyone from Texas, damnit!" Shannon calmly explained that it was most likely spread by insects that feed on the tree’s phloem, although the identity of said insect(s) remained a mystery. Meanie, obviously confused, gave up on any possibility of understanding and said, “do I at least get a prize or something - you know, like the millionth person to check out at the grocery - how about a bottle of scotch?” Shannon answered, “I’m sorry, sir, you do not get awarded for having a disease, at least not by my department.” Meanie’s voice rose, “then what the hell are you bugging me for?” With that, he slammed down the phone.
January 2007 - May 2008
|Central west coast Florida - confirmed TPPD sites|
While I mapped out the growing number of fatalities, hoping to determine where TPPD would next rear its ugly head, Shannon read me the following list of symptoms, which he'd compiled for agents in other counties to be mindful of:
1. Fruit drop and flower necrosis (death) - this one's hit-or-miss, though, because if the tree is not about to flower then it's not something you would see.
2. Leaf chlorosis (yellow coloring cased by chlorophyll deficiency) followed quickly by necrosis. Excess of necrotic older leaves. This won't be apparent if the leaves have been removed, which many homeowners do, and will therefore be a better indicator in the wild than it will in urban settings.
3. Progressive death of spear leaf and bud, along with outer fronds. The only problem here is that if the tree is very tall it might not be visible without getting into a bucket truck.
|As the ratio between red and white marbles|
narrows, the probability of selecting a TPPD
positive tree increases.
4. Weakened or decaying root system.Neither of us realized that our most disturbing discovery of the disease's presence was just on the horizon.
Friday, May 2, 2008, 78°
Shannon and I dashed in and out of our respective houses to pack overnight bags, then got on I-75 south. What should have been a short trip turned into a two-hour journey, thanks to rush hour traffic. By the time we checked in, showered and ate we were both droopy-eyed and headed straight to bed. Tomorrow would be a long day, and we needed all the energy we could muster up.
We pulled into the parking lot of the Manatee county sheriff's office with 15 minutes to spare. "Early is on time and on time is late," I said in my chipper morning voice. Shannon gave me a dirty look and nursed the weak cup of coffee he snagged from the hotel's continental breakfast. At 6:00 sharp, a man in a white convertible Cadillac raced through the parking lot and came to a screeching halt just next to our vehicle. “Follow me,” he hollered. “Alrighty. Good morning, Captain,” I replied, and we pulled our vehicle behind his.
We arrived at the second tree in question - another Sabal palmetto.This one was at least 40 feet tall and had obviously been trimmed. I turned to the Captain and said, "with all due respect, sir, I can't possibly see what's going on with this tree. From here, it looks like there are brown leaves on top of green ones on top of gray ones, which makes no sense. Didn't you say there was a third tree you wanted us to see?" The Captain said, "fine - let's go."
The last palm we looked at was further inland in a neighborhood called Parrish. There was nothing green on it. The leaves below the spear were badly stunted. "Dead palms tell no tales," Shannon said, while the Captain and I remained silent. I circled the tree looking for clues and noticed that the area beneath my feet had some give to it. "Maybe it's climate change - sea level rise or something - but this ground feels squishy to me," I announced, and leaned against the palm's trunk. With that I heard a creak; the tree rocked under my weight. Startled, I leaped forward into the Captain's arms. He caught me, looked me in the eye, and said, "Let's just keep this a professional relationship, alright," then winked. Shannon perked up. "Bingo! I've got it," he squealed, "I'm going to get a tissue sample to be certain, though."
- Tomato Festival Logo: http://ruskintomatofestival.org/images/ruskin-tomato-logo2.jpg
- Mr. Meanie: http://americanvision.org/wp-content/uploads/2011/04/grumpy_old_man38113906_std.jpg, modified by Laurie Sheldon
- Map of TPPD Sites: http://www.freshfromflorida.com/pi/caps/TPPD_maps/TPPD.pdf, modified by Laurie Sheldon
- Marbles: drawn by Laurie Sheldon
- Homer Simpson: http://www.simpsonswallpapers.net/wp-content/uploads/wallpapers/homer_eating_donut_with_sprinkles_wallpaper_-_1280x1024.jpg, modified by Laurie Sheldon
- Captain in Cadillac: drawn by Laurie Sheldon
- Specimen Palm #1: http://edis.ifas.ufl.edu/LyraEDISServlet?command=getScreenImage&oid=14188911
- Specimen Palm #3: http://www.freshfromflorida.com/pi/pest-alerts/images/tx_phnx_palm_decline_fig2.jpg
- Phytoplasma Resource Center: http://plantpathology.ba.ars.usda.gov/phytoplasma.html
- Map of TPPD Sites: http://www.freshfromflorida.com/pi/caps/TPPD_maps/TPPD.pdf
- Tissue sampling process: http://flrec.ifas.ufl.edu/pdfs/LY-TPPD-Trunk-Sampling.pdf