I have found beetles munching away at the leaves of my trees. They tend to eat at the perimeter of the leaves. We have leaf-footed bugs that suck the sap out of the leaves. They tend to work in the middle of the leaf. The leaf doesn't really curl or show a puncture wound, but it does wrinkle around the bug's incision. Both the leaf-footed bug and the beetles are usually out munching at night. I have also dealt with leaf curlers and spider mites. Both spin a web on the underside of the leaf that either causes curling at the edge or wrinkling in the interior. If you take a magnifier to the underside of the leaf, you might see the bugs that are responsible. Last year I took a two part approach to getting rid of the bugs. One I sprayed with neem oil weekly for four weeks. Secondly, while it rained, I would use the hose with a sharp spray on the underside of the leaves. The buggies don't like being wet, which is why they hide on the underside. I think this was more effective than the neem oil. Neither method was effective on the Beetles or Leaf-footed bugs. I'm not sure if a poison would be more effective, I hunt them at night with a flash light. If you flick them, they hit the ground stunned and then a quick stomp does them in. Its actually kind of good for relieving stress. Your bugs may be different, but you should be able to see them hiding on the underside of the leaf or at night. If you decide to use the neem oil (or any other spray, spray either in the morning or at dusk when it is cooler. ~james.

You're in big trouble! Those are Selenite nymphs as described by H.G. Wells in First Men in the Moon. Good thing you killed them, because the link shows what they look like when they grow up. Here is a link that might be useful: Selenite

That is one of my arch enemies a click beetle. The worse part of this beetle are its larvae. I believe they are called wireworms. Twice a year the beetles deposit their eggs in the soil by your plant roots. The wetter the soil the happier they are. I have in the past lost several ornamental grasses to wireworms and a few small newly planted roses. Newly planted perennials have been slaughtered as well. I hate them kill it. They will do serious damage to veggie gardens. The wireworm can survive underground feeding on the roots of your plants for an eternity. Basically morphing once again into an adult to mate. While plant death does not happen often should you dig up a dead young plant look for wireworms. I have found as many as twenty in the hole with a new plant as they are attracted to the loose moist soil. They are considered a serious agricultural pest in some areas. To think that I used to consider them benignly cute them I learned the truth.Wireworms - Missouri Botanical Garden

Not sure, but I had what I called white needle pests on my cast iron plant some time ago. I believe that they were larva of mealie bugs. Not saying what your pest is, just relating an experience with my plants. I would repot your plant with clean soil and make sure you take all the precautions possible- wash the pot and saucer, clean the area around the plant, isolate the plant. I often will spray the roots with insecticidal soap if I suspect critters were in the soil.