Please Help! Problem with Dendrobium blooming...

[Snooze]

Hello, my tall, cane, no name dendro has finished its newest growth, which is almost 3' tall. It has a forked spike starting at the top of the new growth and another coming out of the side of an old growth.

This is great, I haven't seen this plant do that before. I think my attention in the past months have payed off.

However, within the last week or so, the tips of all the leaves on the new growth have turned brown and are now dried and can easily be removed.

Also, the tip of the spike on the old cane has turned dark brown.

The other day, I spotted a few tiny (I mean really tiny) red ants in the moss.

Other than that, fertilizing, watering, sunlight haven't changed much.

I also went pretty deep into the pot and the main roots like great.

My questions are,
What is the cause?
What should I do?