As you can see from the videos below, we have been talking tomatoes a lot lately. Tomatoes, as you know, are some of the most precious of fresh commodities, and their season is a much-celebrated event. While we are all looking forward to eating the first tomatoes of the season, we are also acutely aware of the shortness of that season and the probability that we can get a decent harvest to fill our canning needs throughout the year. And here lies the problem.
Last year, the tomatoes got what is called late blight, which is a fungus. It's the same fungus that caused the Irish Potato Famine. We got it around week 3 of the harvest last year, and lost a good portion of the harvest. It was extremely sad to see all that work we had done being thrown away. This year, the chances of blight coming back are fairly high, since there are most likely spores in the air created by plants that weren't properly killed last year (not our plants, but of other farmers and home gardeners). Also, as you are aware, it has been very rainy and wet this year, prime conditions for fungus.
We got word last Thursday that the blight had been found in Wisconsin already. This is very disheartening as we have yet to harvest ripe tomatoes. We may lose the entire harvest! So Claire sent out a letter to the members of our CSA asking for their input. In the video, she talks about the compelling arguments that people wrote in, in both directions (the members were split as to what to do).
On the SPRAY side, Troy has never used copper to control disease before, so it would be a learning experience for the farmers and the interns to see how effective the copper is at keeping the tomatoes from getting late blight. Copper is just a physical barrier, not a fungicide. The plants will eventually succumb, it's just a matter of time. Application will also help to slow the spread of the fungus across the country. However, while copper is approved for organic application, it is also toxic to people and wildlife, and can cause harm to plants if sprayed often, caused by build up in the soil. See this article from the UW-Extension about the application of copper for organic control of late blight. At Troy, we bought copper hydroxide to use on the plants.
There are also other costs, such as labor time to spray the plants. It would take one person a full 8 hours to do a thorough job. That person would have to wear a hazmat suit, mask, and goggles the whole time. In this heat, it would be dangerous. Rehydration would be difficult and breathing restricted. That person would not be able to contribute to other tasks on the farm, straining our already stressed labor. In order to be effective, the copper needs to be sprayed once a week. Each time, no one would be allowed to enter the tomato field for 24 hours after application.
For those who would choose DON'T SPRAY, the reasons are obvious. As a Certified Organic producer, Troy doesn't spray anything (not even compost tea) on the plants other than water. It didn't feel right to spray a known toxic substance on the plants just for the pleasure of eating tomatoes this year. Just because copper is approved for organic use doesn't mean that we must choose to use it. It's a reminder that organic law is written with production in mind, not necessarily the health of the producer or the consumer. Our customers would need to be reminded to wash their tomatoes thoroughly, perhaps twice.
If you watched the video, you saw that Claire made the decision to spray the plants. Later that day, she did. The next day, we went to Tipi Produce for a field trip. There we saw many new techniques, equipment, methods, and tools. It made an impact on the interns, and on the way back to Troy we continued the discussion. And in the end, all of us (save myself) had decided that not spraying was the right choice for Troy. I was still interested in the experimental aspects of applying copper. I still am, though I would like to study it in a controlled environment. But after reading in more detail about the effects on humans and wildlife, I too changed my mind.
So all of us are crossing our fingers that the late blight doesn't spread to our plants quickly. The heavy rains we got on Thursday and Friday probably washed the original application of copper hydroxide off pretty well. I was heartbroken when we lost a portion of the harvest last year. I really hope that our luck holds out as long this year. Tomatoes are my favorite vegetable (I know, they're really a fruit) and I would hate to go another year without tasting a fresh one.
Who knew there were so many implications to organic control of late blight?