Yellow and black leaves

[DLup]

Hi all,

I am growing seven plants of four varieties in raised beds following my own evolved version of square foot gardening. From relatively early on, the lowest leaves on some of the plants began to turn yellow and black and wither (pics below, maybe sideways in the post but they rotate if you click to open), so I began removing these. Now all seven plants are showing this to varying degrees with some differences even between plants of the same variety. All are generally growing well, all have set a few to about 16 fruits, and all are still producing flowers. The varieties are Black Krim (2), Marianna's Peace (2), Orange Strawberry (2), and Malakhitovaya Shkatulka (Malachite Box, 1), each in a little more than 1 square foot, unpruned in 7 foot tall CRW cages that are 12 inches in diameter.

Given that the tops of the plants seem vigorous, I don't think this is a blight, but I could be wrong. I have been watering every other day with microsprayers and everyone else (eggplants, peppers, kale, collards, cukes, leeks) seems happy with that as the boxes drain well and generally dry out quickly, but maybe this is the result of over watering? Again, given the vigor of the plants, it does not seem to me that root rot is a problem.

I am at a loss for an explanation and would appreciate any thoughts or comments!

Thanks,
David

20150714_090657.jpg (45.52 KiB) Viewed 1352 times

[PaulF]

It looks to me like it is a blight which is soil borne and very common. It could be septoria leaf spot which is also a fungus. Fungicides such as chlorothalonil, maneb and mancozeb are effective against blights and leaf spots. A mulching program to keep soil from splashing up on the leaves is a good idea. I would remove the diseased leaves but be careful not to touch healthy leaves in the process. Late blight usually happens beginning this time of year. Early blight is more devastating and you will lose the plants very quickly. Good luck.

[DLup]

Hi Paul,

Thanks for your comment. I have had them mulched for a couple weeks, but not from the start, and I only water from the bottom with microsprayers, so I don't think I get too much splash from the soil. That being said, we have had a decent amount of rain otherwise and I did have the beds overcrowded with peas that got much bigger and fuller than I expected, which cut down airflow. I will keep cutting away the yellowed leaves, but I know I have not had very good sanitation so far in terms of possible transfer. Alas.

David

David

[lexusnexus]

Keep the mulch away from the base of the stems (same with trees and their trunks). Don't need a disease path.