I've thought about moving the plant to an indoor area that gets plenty of sun, but don't want to do so if there are larva on the leaves.

Any advice? Mahalo.

It was a while ago so Im not sure if you're still having the problem or if it has been resolved. Im an entomology student here on Kauai, so Im definitely interested in finding out what these are.

Definitely seems like you have caterpillars on the plant. If there are no 'pillars to be seen during the day, try waiting until evening, mid-night, and early morning to take a look. Many species of moth caterpillars feed on plants by during the evening/dusk/night hours, and hide by day under leaf litter or in the soil.
There are a few swallowtails on the mainland which use Basil as a possible host plant, but fortunately we only have one species here in Hawaii, the Xuthus Swallowtail (Papilio xuthus) which feeds on plants in the citrus family.
Hope this is some help to ya, if you do by chance find these little critters, Id love to see some photos!

Aloha and all the best,

~Dave
Kauai, Hawaii
Entomology/Photography
Student

Now that you say it gtanaka, Im almost certain you're right. I have some corn growing and the Rose Beetles are going crazy over it. I didnt know what exactly it was at first either, seemed to be caterpillars. Small pellets around the damage on the leaves, so I figured it was caterpillars. I then went out one night to take a closer look and lo and behold, the beetles were going at it right then and there. Not much you can do in this case, picking them off when you find them feeding will save the plant for the time being(as in until another beetle comes along) but as far as I know theres no long term way to solve the problem =/ Ill ask a few friends in the meantime and see what they have to say. Talk to you soon,

Aloha,
~Dave

I haven't tried it yet but I think I am going to get some to treat my spices and young fruit trees.

Aloha from Mountain View!
Alane

http://www.kodakgallery.com/I.jsp?c=agurdu9.1r2e1m85&x=1&y=-d1wqkl&loc aleid=en_US

One is Merit-a systemic insecticide that kills sucking and chewing insects. It can also harm bees if the plant you are treating flowers and it cannot be used on edible plants. I don't recommend use of this product.

A porchlight turned on for about 4 hours beginning at dusk will also keep the beetles away and harms no one. Removing leaves the beetles have been feeding on can help as the damaged leaves release a chemical that attracts the beetles.

Wish there was something like the fruit fly trap for beetles. they cause a lot of damage in my garden.

Thought I'd check back in to see what the result was, I guess I was right in the first place should have stood firm! Oh well, lol!. Yep, those inchworms are a major pest out here. They eat a HUGE variety of plants, including tomatos, squash, corn, herbs and spices, and Ti plants.

If you find them and don't want to kill them, but want to save the plant, relocate to a Ti plant, can't do much harm there and he won't know the difference! I just posted in one of the most recent discussions about these on my tomatos, so it's funny to see them here!

ANY time you find damage on your leaves, and cannot see or find the culprit, check them again at night (An L.E.D. flashlight works the best for these particular 'pillars, as they seem to reflect the light back differently from the leaves and makes it alot easier to see. They turn into a neat little moth too, will post a new thread about this caterpillar with photos.

Don't bother trying to combat these by netting, it won't work very well! These particular moths lay large batches of eggs seemingly in a random location and the caterpillars hatch then travel to a suitable hostplant (or not in some cases...unfortunate for them)
The egg patches appear as a fuzzy brown spot on walls, ceilings, mail boxes, plants, tree trunks, plant supports, plants themselves, anywhere. There seems to be no particular area which they prefer, just as long as those 'pillars can find some food nearby!

~Dave