I'm trying all heirloom tomatoes for the first time this year, and one of my Brandywines has developed these spots. I know the heirlooms are less disease resistant, and I'm wondering if this is something I need to worry about? And if it is, what do I do?
I'm not a tomato expert, but it looks like bacterial speck which is caused from overhead watering or leaving the water on the leaves. Do you water from the top of from the bottom?
http://aggie-horticulture.tamu.edu/publications/tomatoproblemsolver/leaf/bac_spec.html
Definitely something you need to worry about. First thing you should do is remove all the infected leaves. Spray with a fungicide and I would move it away from other plants for awhile just to be safe. I had it on 2 of my plants earlier this year. I removed all the infected leaves 4 different times and sprayed every few days. It kept coming back, so I cut them down and replanted. Hope you can control it....good luck.
If you're organic, you could also sprinkle a light dusting of horticultural cornmeal around the base out to the edge of the branch line. This will act as an anti-fungal and help kill the fungus in the soil. Water less frequently but more deeply when you water and water early in the morning from the bottom so any water that might get on the leaves will have evaporated by the time the hot sun hits them.
Thanks, I do try to go organic; we'll see if I can stick to it where the lives of tomatoes are involved. I usually just water at the base of the plant, but I have to confess, we've had a couple of days where things were looking kind of dry, and I was too lazy to keep filling the watering can...and I just got them with the hose.....I'm so ashamed.
But it does make me wonder--what about all those rainy days we've been having? Should I not be hoping for those?
I would snake a soaker hose around your bed close to the plant stems so you can water without wetting the leaves. That way you can hook up the hose and water the plants without hitting the leaves.
Also a thick layer of shredded pine bark mulch (undyed -- not super black, super red, etc.), coastal hay, pine straw, etc. is also recommended to help retain moisture in the soil.
As you say, nothing you can do about rain except go out in the morning and shake the cage a bit to try to get some of the water off the leaves.
This message was edited Jun 8, 2009 7:20 AM
If these spots are only on the bottom leaves, it may be that your plants were either overwatered or underwatered at some time in the past when the plants were growing Both conditions can cause dead looking spots on the leaves. If the upper foliage and leaves are OK and only the older bottom leaves are spotted, it is usually just a case of over/underwatering at some point in the past.
I heard about using corn meal for fungus control but wouldn't it attract mice?
Can someone tell me- is horticultural cornmeal different from grocery corn meal? would ordinary grocery cornmeal work as an anti-fungal? My veg patch is growing lots of mushrooms.
Yes, horticultural cornmeal is different from the regular cornmeal you buy at the store. You can find horticultural cornmeal at many nurseries, organic nurseries, feed stores, and some health food stores. To my knowledge, it doesn't attract mice or rodents any more than any other thing in the garden.
You could try using neem oil as a fungal treatment for this (after removing the affected leaves) if you want to stick on the organic route. This has the additional benefit of a pesticide also.
