I get this problem on my tomato leaves every year around this time it seems like. The older affected leaves get crispy after time goes by. This happens on Brandywines, Celebrities, Empires, Betterboys. Can't remember it happening on peppers, but right now I have peppers, summer & winter squash, corn, and pole beans that do not have this "problem" on them so it is only affecting my tomotoes or it could possibly just be the row they are in. I do rotate my plants around in the garden every year.
I use chlorantholanil weekly but I guess it doesn't work on it. What in the world is it?
Environment & Growing Conditions:
The tomatoes are grown in the ground in a silty clay loam type soil. It has been dry, hot, and humid here lately, about the same time this started I'm guessing.
I water them with drip tape about every 2-3 days at these ambient temps, which is in the 90's.
In the winter I allow my chickens to graze the crimson clover I sow in the fall and let them poop in the garden. Spring time comes and I fence the chickens out, till in the clover and poo. When I get my drip tape laid out, I use a water soluable fertilizer (ultra sol 20-20-20) about once per week through the drip tape at a rate of 120 ppm N.
Last years soil test:
- pH 7.2 (added sulfur haven't tested again, should be 6.5-6.8).
- P 231 ppm.
- K 408 ppm.
- Calcium 2672 ppm.
- Magnesium 317 ppm.
- Sulfur 20 ppm.
- Boron 1.1 ppm.
- Copper 2.3 ppm.
- Iron 106 ppm.
- Manganese 428 ppm.
- Zinc 16.1 ppm.
- Sodium 17 ppm.
- Organic Matter 4.9%