EARWIG is often overlooked. Because they are snicky. They come out at night like slugs and snails but the are smart and run away and hide. They hide in similar fashion to slugs in the cracks, under rocks/stones, ...during the day. They eat much bigger holes than flea beetle. Also they start with the parts of the plants close to the ground(like slog/snail) while flea beetles eat the top most leaves. Of all these insects, slugs damage is more severe. A big fat slug can eat a whole seeding in one sitting. Another thing is that flee beetles love peppers and eggplant, tomatillo .... all in the nightshade family. FB damage is only critical when seedlings are very small and not when on the established plant. One more thing: Slugs have chewing/eating pattern similar to caterpillars. The will not usually eat in hole or circular pattern. This post was edited by seysonn on Wed, Nov 6, 13 at 5:53

It's a caterpillar. Doesn't matter much as to which one because they all eat plants. If it's eating something you would rather it didn't, flick it into soapy water or cut it in half, or stomp it. One that size is far too old/mature to spray because it will easily get to the next developmental stage.

Might be Blister Beetles? Below is a pic of several varieties as they come in many colors and stripe designs. The most notible feature of BBs is their "ant-like" head. vgkg Here is a link that might be useful: BBs

If there is an outbreak of insect damages that require using a product that can control them, then its OK to use. I try to avoid any 'do it all' broad spectrum products as they have many more issues with side effects and can cause build up resistance. I am not trying to condone the use as a continual spray used every week. Usually two sprays of any thing are necessary to break large cycles of insect damage. My fruit tees are never sprayed, and I have no worms in my apples. There, I use sticky traps and scent lures. If no improvemnt is seen, after two spray treatments, then other means must be studied. I am quite sure that people don't go out at night and use a microscope in their garden to see what is causing the damages mentioned. Typically leaf eating insects respond well to th Bt product, no matter what kind they are are. Its safe to use, only because it can be applied to edibles, without issues of any side effects to humans. If we were to consider using it on a steady basis, it would soon become as resistant as many harsh pesticides. My info here is to guide someone ito a safe area where they can try this product and see if it reduces insect damages. I would hardly think anyone would pour it on a plant straight out of a bottle on a daily or weekly basis, as we are not really idiots here. I have used it in the past with great success and will continue to us it, as opposed to petrolium based sprays, systemic pesticides, or any other questionable bio hazard products. Everything in nature has a negative effect somewhere, and if we continue to use strong means to cure minor issues we can quickly run out of viable options. Last year, 99% of all my 10+ varieties of leaf lettuce were perfect with maybe a single small hole in a leaf in a single plant. I use things like beneficial nematodes and water these in before any plantings. With all the leaf lettuce I grew and no indications of any serious damages, I was quite happy and never used any product of any kind to protect the minor damages I saw. On the other hand, broccoli had small green caterpillers and these only showed up when I blanched the crowns, and saw them floatng in the boiling water. I didn't spray there either, as it wasn't like I was seeing totally lost broccoli crowns to insects. Just dont try to scare people into some diection where they may decide to use a more powerful product without regard to first trying something that has less of an impact on nature. I bet you also dislike using milky spore for Japanese beetle grubs.. Around here, gypsy moth caterpillers still kill many huge oak trees, and the green ones do serious damage to my fruit trees leaves. I don't have oaks on my property and must deal with overhangs from neighbors. I can't build a wall high enough to block the bugs coming from the trees. Corn earwroms are another issue too, as they can damage a whole crop. I let birds forage in my garden as I feed them in winter. I allow toads and snakes to reside here too. I have a bug spray that my dad boughr years ago, that can also kill earthworms. I do not use such a thing here. In fact, I must have about 15 bottles of nasty stuff left over after the ban on DDT. Needlss to say they never get used and will have to be displosed on an earth friendly manner. So you are the 'expert' here, what do you insist on using on controlling leaf damages instead?