Uh-oh, what kind of crud is this?

[hunter]

I've found this on a couple plants in Earthboxes. Also found on the plants were a few cucumber beetles. Otherwise, plants seem healthy. This is affecting new growth.

I haven't been spraying EB plants with anything, which I am now regretting.

[Shapshftr]

Looks like blight

Edit: Actually now I see a little white stuff on the top of the one leaflet. It could be powdery mildew. Once it attacks it moves fast. You should start spraying with neem oil immediately.

[ginger2778]

I'm afraid I agree. This might need the bleach spray. And better hurry.

[hunter]

Awesome... Lol. I may just pull the sucker. Any ideas how the blight could have gotten on the plant since it's in a new Earthbox? Bugs?

[Worth1]

Air born spores.

I want to add you can and should amputate the effected leaves.

[ginger2778]

Yes, airborne. Fusarium is soil borne so not likely to be gotten in an earthbox, but Septoria, early and late blight( I think this is the latter), several bacterials all can ride in on wind and rain.