Basil is a leafy herb that is enjoyed not only by humans but these contacorous pest called Asiatic Beetles.
I never had a problem till 2014. I did some research and found they have actually been in the US since 1922.
Well one season I planted a whole edging bed of basil. These beetles found the plot and reeked havoc.
I said what the heck could've destroy my beautiful bed of basil. So I did some detective worked looked in the early morning found damage. Then worked one night late and was up dead heading my pansies and low and behold on the leaves were brown beetles happily having a feast. I captured one and the others fell to the ground and scurried under the neighboring plants burrowing into the ground. I was horrified. I have a light post not too far along my garden walkway path to my front door. My kitchen garden is about 5 to 10 feet away.
I spoke to a friend at the extension office and this is what I discovered.
These beetles are attracted to light I read. They also mentioned placing a mesh netting to protect your plants.
I did try the insecticidal soap since this is an edible plant. It really didn't help much. I really soak them well too.
Someone recommended hanging a light and placing sticky tape under the light. Tried that didn't work.
Putting soapy water near the light they are attracted and they fall in.
But the extension office gave some advice. You could plant then in a container and place them up in your screen porch. Anyways I hope this helps you.
Good Luck. Let me know if any of you have some suggestions. I'd love to hear from you.
Nasty pest the Asiatic Beetle