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.)
(Please start by playing the following video)

This is the city: Ruskin, Florida. Located on Florida’s central west coast, Ruskin occupies about 15 square miles of land in unincorporated Hillsborough County. From 1934 until the early 1950s, the major social event of the year was a Tomato Festival. We’ve stepped things up a bit since then, but we’re still something of a sleepy little town with a population of about 17,000… so when a deadly disease makes its Florida premiere in our backyard, I go to work.

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.

8:45 A.M.
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.

9:15 A.M.
Disease trajectory
Shannon trudged through the office and over to my desk, then promptly demanded an explanation for why he had to come in early. “Remember that grumpy old guy whose date palm we sampled a few weeks ago?” Shannon nodded. “Well it doesn’t have lethal yellowing,” I said. Shannon’s eyebrows raised, “no? Then what?” “You might want to sit down,” I replied. Shannon pulled up a seat, looked me in the eye and said, “okay. Enough of the drama. What gives?” I cleared my throat. “It has Texas Phoenix Palm Decline,” I asserted, in my most official-sounding voice. Shannon busted out a, “Whoa, but that doesn’t exist in Florida!” “It does now,” I countered. “We’d better call that man to give him the news. What was his name again?” Shannon ran over to his own desk, rifled through some papers, and came back with the homeowner’s name and telephone number. “Curt Meanie. 813-645-6465. Do you want to call him or should I?” I pointed at the phone receiver then pointed back at my partner.

Mr. Curt Meanie, the host with the most.
9:30 A.M.
“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
Over the next year and a half, the calls poured in from homeowners, nurseries, and park managers throughout the central west coast. Palms in southern Hillsborough and Manatee County had been hit hardest by this new disease. Neighboring counties, including Polk, Sarasota, Pinellas, DeSoto, Hardee, Highlands, and Lake were not completely unscathed. We had documented its presence in four different Phoenix species: Silver date (P. sylvestris), Canary Island date (P. canariensis), Edible date (P. dactylifera), and Senegal date (P. reclinata). When the lab confirmed that the phytoplasma had infected a few Queen palms as well, to tell you the truth, it didn't bother me so much. They're messy, susceptible to frizzletop, and they aren't native. I've never liked them anyways.

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.
I interrupted, "all of these qualifiers make your list a bit soft to use for field diagnoses. It sounds exactly like lethal yellowing to me. Have you not found any differences between the two?" Shannon snapped back, "wait for me to finish, wouldya? We can't run around testing trunk tissue on every palm. Aside from the fact that it's expensive, it's a crap shoot.Think of it as searching blindfolded for a red marble in a bowl full of white marbles. If there is only one red marble (a TPPD positive palm) mixed in with the white ones (TPPD negative palms), the likelihood of selecting the red marble blind folded would be slim. The likelihood of selecting a red marble increases as the number of red marbles increase. Get it? Where was I? Here we go - the last symptom on my list, which is unique to TPPD." He continued:
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°
Mmm... Donuts.
We were on our way to punch out when Captain Crunch called Shannon and I into his office. "Boys," he said, "I need you two to take a little trip south. I just got a call from Captain Caveman down in Manatee county asking for our help. He's got three questionable palms for you to look at. You boys have the most experience with palm diseases, so I told him you'd meet him tomorrow morning at 0600. I took the liberty of booking a room for you at the Days Inn Bradenton around the corner from his office so that you have no reason to be late. Hope you didn't have any big plans for the weekend. Good luck." We turned to walk away, and he called us back. "One more thing, if you would. Please bring back some doughnuts - with sprinkles." We grumbled as we left his office, then headed for our patrol car.

5:30 P.M.
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.

Saturday, May 3, 5:45 A.M.
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.

6:01 A.M.
Specimen #1
We headed north on 9th street, over the Green Bridge, and into the Palmetto neighborhood where we stopped in front of a Sabal palm. Its oldest leaves were a warm gray color and obviously dead. Those further up the tree had a reddish tinge radiating from the leaf tips. A half dozen young, green leaves formed a halo above those, encircling a dessicated spear leaf. Neither of us had seen anything like it. The Captain was brief, "any ideas?" Shannon and I both shook our heads side-to-side. The Captain suggested we go to the other sites, and once again we were off.

6:20 A.M.
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."

Specimen #3
6:45 A.M.
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."


Stay tuned for the exciting conclusion of AGNET - The Palm Tree Whodunnit!

Image Sources

Additional Resources


Write so many information on different topics are a symbol of professional writer and have a deductive approach.
Anonymous said…
thanks for sharing.
Under Fri May 2nd, "boys" (maybe a campy way to refer to a mixed gender group) - Under 6:45 am - "leaped forward into the Captain's Arms" More jocular camaderie if the leaper is a guy. tm
Ha ha! Thanks, Travis. It's little late for editing, but thanks for your feedback. One of these days, this story will end and we'll know who's responsible for all of these deaths... (insert ominous music here)

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