Start reading about tomato pests and diseases and you begin to wonder how any tomato ever makes it at all. After weeks of episodic rain my tomato plants are growing like kudzu, but I noticed something this morning that sent me looking for fungicide recipes: yellowing around large brown spots on the lower leaves of one of the plants. I am not happy about this.
Early Blight is a fungal disease that is easily transmitted from infected soil, tools, some insects, (ex. aphids), or any type of physical contact. It can live up to two years. Wet seasons like the one we’ve been having provide ideal conditions for it to survive and thrive. The lower leaves are affected first, yellowing and falling off.
Some of the most effective controls are:
- Removing the lower leaves, especially those which contact the ground
- Mulching to reduce splattering of the fungal spores up to the leaves
- Watering the soil, not the plant, to keep the plant dry and inhospitable to fungus growth
- Spraying with copper or sulfur–use caution, too much copper can harm earthworms
- Serenade Disease Control has gotten some good buzz. It’s listed as approved by OMRI (Organic Materials Review Institute)
- Neem oil, especially as a preventative before the blight appears
I removed the lower, affected leaves, added some fresh mulch, and sprayed with a baking soda solution (1 T. baking soda, 1 T. oil, squirt of liquid soap/1 gallon of water). Of course, 30 minutes later it rained again, so I’m anticipating a battle with this. For the benefit of the plants yet to show signs, I am going to hit them with neem oil. I’ve heard a milk solution (1 part milk to 9 parts water) is also helpful so I may try that, too– if it ever quits raining! Remind me how I wouldn’t quit whining about the nonstop rain when the next drought hits . . .
This is an article about pruning the lower parts of the tomato plant for this reason.
And this is a discussion about Early Blight on GardenWeb, one of my favorite resources.