Curly top virus, spread by leafhoppers, killed 90% of my tomatoes in 2003. With this project, I wanted an organic control for the leafhopper population to thwart the spread of curly top virus on my farm. I discovered that leafhoppers do not like shade, so I aimed at shading my tomatoes for their first few months of growth. I hoped that once the plants were well established, they would not succumb to the virus. Unfortunately, I was unsuccessful. Many plants died under the shade, and 90% were dead after three months.
My primary objective was to find an organic control for curly top virus.
I planted four, 120” long beds of tomatoes, with 40 tomatoes per bed. I planted one row without plastic mulch and a cover for a control. I planted one row with only black plastic mulch and another with black plastic mulch and a covering of clear agro-fabric. I planted a fourth row with black plastic mulch and a covering of silver agro-fabric covering. The tomatoes I used were transplants, planted between May 15th and June 10th.
The first tomato deaths were in the plastic-covered beds. It was very warm and a few plants perished because their roots were not directly under the drip-tape irrigation lines. My soil is sandy, so the drip tape needs to be directly over the plants’ roots, especially in the hot summer months when plants are not yet established. I used ground staples to secure the drip tape in place to avoid this problem, though I still lost six plants.
I soon began losing tomatoes in the uncovered beds from curly top virus. Initially, it seemed the covered beds were not contracting curly top, but about three weeks after planting, I noticed death under the covers as well. I separated the dead plants from the rest of the crop.
Ultimately, I was only able to harvest from about 17 of the original 160 plants. The deaths were in all four rows, with none faring better than the others.
IMPACTS ON AGRICULTURE
Finding an organic control to the curly top virus will have a significant effect on agriculture, specifically in the Southwest. For two successive years, I have lost my cash tomato crop and can’t continue planting it because I’m losing a substantial part of my business.
I presented this project at a conference in Brigham City, Utah, titled “Diversified Agriculture.” Roughly 35 people in attended.