Friday, September 28, 2007

It's not the heat, it's the Phytophthora. Maybe.

Thousands of times we've said to customers who buy our plants, "They love the heat, but don't overwater." Yet this year, in the heat of August, we began losing plants. First our Abrialli lavenders started declining -- one or two plants would wilt, right next to healthy plants that received the same treatment. In a few days more would appear weak. Within a month, all of what had been our healthiest plants were dark and wilted. It was hot, right in the middle of August, and being Oklahoma it didn't cool off significantly at night. And it had been a wetter than average summer although the field could not be called wet at all. In September we began seeing the same trend in our field of Provence which, too, had been healthy and strong.

This is our fifth year growing lavender and we know more now than we did when we started. But in trying to figure out our problem we felt helpless. What could we have done wrong? Call it a case of choking -- the same phenomenon that lets a basketball player miss a shot he'd make any other time right when it matters most.

We needed fresh perspectives, so we called our friends Emily and Mike, nearby organic vegetable growers, who stopped by to see our field. They began asking questions.

"Did you harvest and prune the dead Abrialli?" -- Yes, we harvested them in June and pruned a few weeks later.

"Did you harvest and prune the healthy Tuscan next to the Abrialli?" -- No, the Tuscan didn't bloom this year, and we didn't bother to prune them yet.

"Is there any chance you harvested only from the Provence plants that are now dying?" -- Unlikely, but possible, and we started to see where this was leading.

Mike said, "You've done everything right. There's good drainage, the plants are spaced well and get lots of air circulation." Furthermore, we must have created favorable conditions because the plants had grown well until recently.

Emily and Mike are experienced farmers, much more than we are, and they were unsure of our situation. But their questions led us all to suspect a fungus or disease that is triggered by hot and humid conditions, and spreads, among other means, by hand tools. This would explain why plants that had been harvested and pruned were suffering, while those that hadn't been touched were fine.

To try and verify our suspicions we dug up two plants and delivered them to the Oklahoma State University Extension Office in Tulsa, and left them with Sue Grey, a great asset to local growers and a true professional. We'll have to wait for a culture to be grown off the plants to determine a specific culprit, and then decide how to treat the field. We're not a Disneyland lavender field where everything is perfect, so look here in the future for what we discover and decide to do. Early suspicion points to Phytopthora, a fungus that is widely present in Oklahoma soil and is active when temperatures reach 90 degrees with 90% humidity. We'll have to wait and see.

We're frustrated and hampered by the death in our field and want to know WHAT it is, WHY it happened and WHAT NOW. Of course, nothing is that easy, which is why the lavender business keeps our interest despite rough times. Figuring out the problems IS the point.

What interested us the most is how the very educated and experienced people we engaged in this problem were reluctant to tell us what to do. They didn't know, and they knew that they didn't know. Always be wary of those with answers.

We'll update as to the pathology findings, possible solutions and outcomes. And we'll reconsider our line about heat and watering. It's not that simple.


Anonymous said...

Chris, I met you at the Jenks Festival and have followed your blogs. I purchased Promot Plus and now I am not sure when to apply it. I am going to side dress using a sprayer tank. We have 1 year old plants and 3 month old plants. I purchased about 20 plants from you and you noted that they had been dipped in Promot. I have about 300 new plants, mainly Orovence and Grosso with a few munstead and and hidcote. I am starting to lose some of the grosso (not the ones I bought from you). They just turn a dusy light color and dry up. When I pull them, the roots are not wet, but not dry either. I am losing three of my larger 1 year old plants, but 90 % of them are great. My question is when do you spray. morning, evening, before or after a rain. I can't get that info from the label. Just curious on what you did. Dolly Bonfy

cdykes said...


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