Experts and BHG readers answer.
Thanks for writing. You can try spraying an insecticide containing the ingredient spinosad and see if that helps. Spinosad is an organic product that only affects insects that eat the plant.
If you think it may be a different kind of pest, such as deer/rabbits/etc. then you can try an animal repellent such as Liquid Fence, Deer Stopper, etc.
---Justin, Senior Garden Editor, BHG.com "