All the pesticides recommended for preventative application for bark beetles are highly toxic to honeybees and other insects. Carbaryl (the active ingredient in Sevin®) is slightly toxic to birds (LD50 > 5,000 mg/kg in mallard ducks and bobwhite quail) and fish (LC50 = 1,950 mg/L in rainbow trout and LC50 = 6,760 mg/L for bluegill sunfish). Permethrin (the active ingredient in Masterline Plus C®, Astro®, and Dragnet®) is highly toxic to fish (LC50 = 0.5 mg/L to 315 mg/L) and aquatic arthropods (LC50 = 0.2 mg/L to 7.6 mg/L). Permethrin is slightly toxic to birds (LD50 > 3600 mg/kg). Longer dietary studies showed that concentrations of up to 500 ppm in the diet had no effect on bird reproduction. The oral toxicity for mammals is low (LD50 = 600 mg/kg). Bifenthrin (the active ingredient in Onyx®) is highly toxic to fish and aquatic arthropods (LC50 values range from 0.0038 to 17.8 μg/L). Onyx is slightly toxic to both waterfowl and upland game birds (LD50 values range from 1,800 mg/kg to >2,150 mg/kg). The oral toxicity for mammals (rat) is moderate to high (LD50 = 153 mg/kg). Talk with a certified pesticide applicator to determine which pesticides will be best for your needs and area.
Jeff Schalau, Associate Agent, University of Arizona, and Tom DeGomez, Area Agent and Regional Specialist, University of Arizona