Primrose

Your guess is quite correct. Freshly hatched slugs rasp, but they do not tear holes out like the bigger ones. They are very difficult to bait as they tend to stay on the plants or in the soil under the plants.Sluggo is a great choice for the organic gardener as soon as they start coming to the bait. Until then you can test spray a small area with a 50/50 solution of plain ammonia and water. Usually this will not burn the plants but will kill slugs. The trick is getting the spray in contact with the little slugs. You can even spray this (not to excess) on the soil around the affected plants. We wish we had a much better solution, but nightly patrols with a cotton ball will frequently yield a lot of the little guys. They seem most active well after dark until dawn. Good luck!