As of late, one of our plants has been loosing most of it's leaves. It began with the tip of each leaf turning brown, some with splotches of yellow. Some leaves even had small holes in them. After a while, the leaves took about 3 days to turn solid yellow then fall off. Our first guess was aphids or some kind of bug, so we purchased a spray claming to kill the pests. However, the death of the leaves continued and there have been no holes in newer growth.
Recently, I purchased a cheap plant from Wal-Mart and added it to our window shelf. This plant has leaves that turn yellow and brown and fall off as well, making me think the new plant spread some diease to our plant. However, I don't know how to treat them and at the rate of leaf-loss we're at now, our plant may be dead within a month or so. Even new growth is looking a bit weak.
We also have another plant looking a bit wilted and my bonsai tree (juniper) looses the occasional cluster of needles. I am afraid the problem will hurt more of our plants and I hope someone can help us.
I can post some pictures tomorrow once I get my camera if that would help.