Porch Pests: Cycad Blue Butterfly

Are you familiar with Cycads? I'm sure you've probably seen them, and think they are palm trees. Cycads have hard and pointy leaves growing out of a crown. Catholics in West Malaysia often use Cycad leaves during Palm Sunday (ironic because they aren't palms) to commemorate Jesus' entry into Jerusalem. The couple of Cycads in my garden had always been doing well until recently. Fresh shoots from the crown all fell prey to little caterpillars, which turns out to be larvae of the Cycad Blue Butterfly. Before the shoots have enough time to harden, the voracious little critters would have munched on them all. I tried neem, physically picking them off, but there was just too many of them. So annoying! Any ideas to get rid of this infestation?