About 3 weeks ago, what was a healthy fern suddenly had some fronds defoliated overnight thanks to some caterpillars! I removed them, but also found teeny tiny babies lurking here and there. I gave it a good bath, sprayed under leaves as well, and then sprayed with dormant oil all over, including in the soil. I haven't seen another caterpillar, or had any fronds chewed upon since Within a week, the remaining healthy, untouched fronds, began to discolor and turned a brownish-grey, which I chalked up to too much dormant oil spray, or being sensitive to it. However, they felt very dry to the touch, but were not brittle. Soil was moist. A week or so went by and new fronds continued to grow, but eventually would turn crispy and die. So, 2 days ago, I noticed that one really green emerging frond began to brown at its tip, so, I gave it a good watering and it seems to be doing ok, and hasn't browned any further. I mist it at least once a day. (I think the problem with this one was a combination of under-watering and reaction to the dormant oil spray).