24OZ Neem Oil
For Neem Oil. I don't think you can get it at walmart but i could be wrong.
I found this about your problem at...
Marijuana
Cutworms, Caterpillars and Larvae
Insects that are in their early stages of development are problem pests because they are insatiable and will eat anything green that they can get their tiny mouths around.Their appetite is surreal when you actually discover how much a caterpillar can consume in a single day. One caterpillar can reduce an ounce cola to stem and stalk in less than four days. These pests pose a huge threat to your crop and must be stopped right away. Caterpillars especially like to eat young seedlings and new growth. They are also known to leave holes in leaf but other pests can do this too.
The only sure way to get rid of cutworms, caterpillar and larvae is to use a cutworm, caterpillar or larvae repellent. Usually the same product will affect all three pests. Cutworms can also be hand picked from your grow. At night they sleep in a XC' shape in the soil or under the cover of something else like a piece of wood.