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Pierce's Disease?

The single most influential event that caused the wine industry to leave Los Angeles was the arrival of the intercontinental railway in 1876. Connecting the city to markets and populations throughout the rest of the United States triggered a rapid industrialization and a great hunger for land to build on. Another influential event to bring about the end of this great Los Angeles winemaking tradition was a terrible blight that attacked the vineyards. This blight, which is still with us today and is called Pierce’s Disease, is a bacterial infection spread by bugs that feed on grapevines, particularly the “glassy-winged sharpshooter.”

Down in Willowbrook, we thought we might have Pierce’s Disease (PD) because leaves on certain of the plants were yellowing and turning brown around the edges, then falling off the stems. I was alarmed because just a few weeks earlier, I had seen one of the sharpshooters sunning itself on one on of the plants. (I later learned from Janine Biane at Rancho de Philo Winery that I should have just removed the leaf that the bug was sitting on). Googling around, I learned that the University of California at Riverside had been engaged in a program to eradicate the pest through the introduction of parasitic wasps, which lay their eggs in the larvae of the sharpshooters.

I was able to contact entomologist and graduate researcher Matt Daugherty at UC Riverside. Matt was interested in seeing the vineyard, not only because of its urban setting in South L.A., a neighborhood of the city not known for its vineyards, but also because the area had not been previously designated as being at high-risk for PD.

Matt came down to Willowbrook a week later to examine the plants. He explained that he’d been in Sonoma when I contacted him because PD, usually associated with warmer climates, had become an issue there as well and also a major threat to the states' economy. After studying the plants, Matt said he wasn’t convinced that they had PD. He noted that young plants do all sorts of things in their first year, and that these could just be young vines being young vines. I was relieved. But there was a divergence of opinion. I also showed pictures of the plants to legacy winemaker Don Galleano, who was helping to guide me through the process of planting my first Mission vineyard. Don, who unfortunately passed away last year, took a look at the photographs of the vines I showed him and declared them to be infected with the dreaded disease. The solution? Tear them out before they infected the other vines. Then re-plant.

I was undecided. On the one hand, we had a scientist who was cautious about diagnosing a disease that may or may not be present; on the other hand, a winegrower with a lifetime of experience growing Mission grapes who saw no reason to wait and risk the health of his other plants. For him, it was a matter of economics. As I saw it, this was a choice between science, with all its fuss about observation, experimentation and testing of theories against obtained evidence, and the hard, cold reality of profit and loss.

Still not sure, I turned to Rose Pinkney, the organizer of the garden. Now, Rose, it should be mentioned, is a woman of faith. In fact, at our meetings, and especially when volunteers come to help us weed, she reminds us that the Willowbrook Community Garden is a ‘prayer’ garden. And then she leads us, or asks one of us to lead, in a prayer for the health of the garden, the community, the planet and the world.

Still mulling the decision about what to do, I suggested a compromise: Leave two or three of the ‘infected’ plants and dig up the one that looked to me to be the most compromised. Call it the Tiny Tim of the vineyard. It was a compromise that surely would not have pleased Don Galleano, since it takes only one infected plant to compromise the rest of the vineyard. But I thought if that happened, it would still be instructive. And after all, our business in the vineyard was not to turn a profit, but to learn. Rose agreed but felt differently. She said to leave them all. God would protect the vineyard. At first, I was not satisfied with this response. But we left Tiny Tim alone with his 11 siblings to face the onslaught of PD on their own. No matter what, I thought, we would surely learn something.

Well, it’s been three years since then, and it turns out Rose was right. All the vines are still alive, and they are all producing sweet, complex Mission fruit. Even Tiny Tim. And I surely learned something.


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Barbara Scales
Barbara Scales
May 22, 2022

Thanks for the story and the impressive reasoning process. Surfing the waves of fate?

Replying to

Hi, Barbara. I just saw this. It's been so long since I've written one of these. I wrote one today, though. Almost two years have passed.

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