Preventing Rodriguezia bud blast... ideas?

[boytjie]

Hello orchid folks, I have a Rodriguezia venusta that has me all excited because it has its first spike; never managed to get it to spike before. It's growing in a four-inch basket in fir bark, hung about six inches under a T5 fixture. Unfortunately, it appears the last (hindmost) bud has yellowed before maturing, and is about to drop off. Any ideas how to keep that from spreading to the rest of the buds? The plant shows really healthy growth and roots, otherwise. Thanks for the assistance!