You'll notice what looks like an aphid on there. That probably is a green peach aphid. I've been fighting them for months, and have kept their population way down.

ditto on the aphids...

biscgolf7: You think aphids are causing all the problems? There have been maybe 10 of them on the plant, tops. The dusty appearance is usually associated with spider mites, but I don't see any.

Are you fertilizing? Could it be fertilizer burn?

How do you water?

Josh

I guess it could be fertilizer burn. I usually add weak fertilizers to my water. But I'm using the same water on all my peppers.

I water about every three days, 1/2 inch or so. I have a moisture tester. I might be overwatering.

I'm baffled by how odd the tops of my leaves look. And the ghost peppers and banana habs are doing great.

looks like you may have some whitefly damage to me in addition to the aphids... in my experience the 2 often go hand in hand... does not look like you have a mite problem to me. generally whiteflies and aphids thrive at somewhat cooler temps than mites.

first thing i would do is move it away from your other plants (or destroy it all together). if i were trying to save it i would also remove the most damaged lower leaves.

I have never seen any whiteflies, and I think I'd notice them. The discoloration of the tops of the leaves (the dusty or dirty appearance, very visible in the middle picture) seems very unusual and distinctive to me. What could do that?

My plants start looking like that when they get a lot of aphids. I don't know if it'sthe aphids themselves or some disease they spread.

In case anyone else experiences this problem, it was diagnosed by microscope as Leveillula Taurica, a form of powdery mildew. Normally this is just a minor nuisance, but apparently my Devil's Tongue peppers are unusually susceptible.

The diagnosis came a bit late for some of my peppers, but others are doing much better. The treatment is two teaspoons of nonfat powdered milk dissolved in a pint of water. You spray it daily, ideally just after sunset/dark, on all affected leaves (tops and bottoms) and stems. The mildew basically falls off. Two days have already made a large difference.

Of course, the leaf damage remains. Severely-affected leaves, especially larger, older leaves, should be removed.