Answer: I'm not sure what caterpillar you are seeing, but I suspect it will turn out to be a butterfly rather than a moth. Your dilema is common to butterfly gardeners. Most will remove some caterpillars and allow others to remain and form butterflies. This way you can find the mid-ground between keeping your plants from being totally eaten and removing all caterpillars and thus the butterflies. Hand picking caterpillars is certainly an option (though not for the squimish) but you have to stay at it as new caterpillars continue to appear. Caterpillars tend to be specific in their dietary habits, attacking a very limited number of plant species. This makes them easier to keep an eye on and keep under control. When sprays are necessary, there are several organic options that break down rapidly in the environment, such as Bt (sold as Dipel and Thuricide_. However, these are a last resort and in most cases will not be needed. Good luck with your butterflies!
Q&A Library Searching Tips