Your shriveled flower spikes are classic thrip damage. Thrips are an insect too small to see with the naked eye but the damage is easily identified when the flower buds shrivel up. The thrips suck all the moisture out of the buds and it looks like it was hit with a blow torch.

Thrips love Dendrobium buds. They will eat any flower bud but Dens and Vanda are the first to go.

Thrips are everywhere and attack flower buds when it is hot and dry as they need water. You need to treat before they attack based on the weather. The first hot month of the year without rain and you have thrip damage. They have been extremely bad in Florida this year with three straight months of heat and no rain.

Thanks orchidsamore. I think you're right. That same Dendrobium has been growing beautifully since it flowered. There is a psuedobulb about 1 1/2 feet tall and I've enjoyed watching it grow beautiful, healthy green leaves very quickly too. --- That is, until insect damage!!

A week ago I noticed the top leaves of the new psuedobulbs began to get tiny yellow holes on the leaves, getting more and more plentiful until the base of the new leaf growth was being attacked. I put some pesticide but unfortunately I think I put too much and have now contributed to the leaf damage :dumb: Yep I feel a bit ridiculous.

Researching now best means of thrip control...