In all likelihood, it's not an infection, rather, it's likely the plant's way of expressing its dissatisfaction with some or one of the cultural conditions under which it grows. I'll mention that low humidity can be a contributor to necrotic leaf tips and margins, but isn't something that should be treated as the primary cause. The primary cause usually lies in the triangle created by soil choice, watering habits, and the level of soluble salts in the soil. Soggy soil conditions and the low oxygen levels that accompany them when using highly water-retentive soils based on fine particles (peat, compost, coir, sand, composted forest products .....) impair root function, which inhibits the plant's ability to efficiently move water to the plant's distal parts, which would be leaf tips and margins. Accompanying that issue is the build-up of soluble salts from fertilizers and tap water that comes from watering in sips in order to stave off the impaired root function, or worse, the fungal infections that cause root rot.

Unless you actively address the water retention of water-retentive soils, problems are virtually assured. There is no way around that issue - you either address the problem or endure its effects.

There are 2 ways to address the issue, and watering less isn't one of them because it promotes the build up of salts. One way is to put mechanisms in place that reduce the amount of perched water a soil can hold. It's not the best way, but it offers some relief, and I can direct you to some information that will help you deal with water-retentive soils if you like.

The best way, by far, is to eliminate the problem issue that created the limiting triangle in the first place by adopting a soil that allows you to water copiously at will, w/o the fear of root rot. This is achieved by increasing the particle size of your soil ingredients so at least 75-80% of the particles are larger than about 1/8". In most cases, this can be best achieved by STARTING with a large % of pine bark as your soil base, or by combining other ingredients that yield a chunky or gritty soil of predominantly larger particles. These soils don't support significant volumes of soggy soil at the pot bottom, which allows you to water correctly (so you're regularly flushing accumulating salts from the soil) w/o concern for impaired root function or root rot, the former being by far the most likely reason for the spoiled foliage on your plant.

I don't know how interested you are in finding out more about what I just touched on, but the advantages of well-aerated and free-draining soils extend well beyond the points I just mentioned. Let me know what you think, or wait for a second opinion if you think that might suit your needs better.

Best luck.

Al

Nothing to add except to say that I only trust how heavy the pot is to determine when to water, for almost all plants.

Love the "Curly / Moe" thing! Best wishes to both plants!

Was reading your profile and your shady container garden sounds awesome! I agree with you about zone preferences, lived in 5b for decades. Brrr!

My partners in green,

Thanks to all of you! I responded to the first 2 through email since that was available, but wanted to also thank purple in opp (I'd love to know the story behind that) and say that the weight of the terra cotta pot, even when dry, is too heavy for my multiple repetitive stress injuries. I had to get help putting it onto the rolling plant stand so I don't try to pick it up! However, from what all of you said, it's best that I didn't put it in plastic for it would take even more time to drain. Curly is happy today, I'll let you all know if more brown appears and thanks again for all your tips!

It usually helps to know which plant it is, there's quite a variety of Philos and they often require quite different environments. Most are epiphytes and grow on the trunks of trees or sometimes rock faces. Their roots are mostly exposed to the air. Most rainforests go through dry periods. Those in deeper gullies/gorges/valleys get high humidity levels even in the dry. Those from more open lowland forests can take more drying out and lower humidity levels. But the main thing is excessive water drains away almost instantaneously after rain and there's plenty of air circulation around the roots. In their habitat they usually operate on a low nutrient basis. Bird or animal droppings may give them a little boost from time to time, but generally they only have decaying vegetable matter on the surfaces they're clinging to. And that very low in nutrients. So over fertilising can be a problem. They'll usually do best not so much in soil as a more open airy mix. But maintaining humidity is important. As Toni mentioned, air in houses can become very dry.

nyad, sorry to hear about your injuries! Seems every time I make the "feel how heavy the pot is" suggestion, it's to someone who can't pick up pots. I don't know what your injury is, but I sympathize and empathize. For the past few years, I've been trying to recover from an injury to my back also, can't really pick up anything over about 15 pounds, and a good day is when it only hurts a little. I do have a lot of little pots and some way too big to even scoot, so I try to jiggle those big ones to gauge their weight. But since they're all plastic, that's surely a lot easier than if they were much heavier clay. If that's not do-able for you, I certainly understand, and the judges won't deduct any points. (smiles!)

I wish there was an interesting story behind my moniker, but it's just that I love anything purple (except a bruise!) and I live in Opp, AL. Not sure where you are, but looks like we're in the same zone. Good luck with Curly and Moe!