April 25, 2000
Question: Four years ago, I bought a bottle of insecticidal oil. I have not used it in more than three years. Would it be okay to use it now?
- Jeff M.. Fort Myers
Answer: Probably not. Under normal conditions oil and water do no mix. An emulsifier is added to the oil to allow the oil to mix with water. This permits the oil to pass through the tiny holes of the sprayer without clogging the holes. Unfortunately, these emulsifiers do not remain stable for more than a year or two. After four years, there’s sure to be a problem getting the insecticidal oil to mix with the water required for application. You’re better off getting a new bottle of insecticidal oil.
Stephen Brown is a horticulture agent with the Lee County Extension. To submit questions call the horticulture desk at 461-7504 between 9 a.m. and 4 p.m. or via e-mail at
shb@gnv.ifas.ufl.edu. Listen to the ‘Garden Show’ at 8 a.m. on 1200-AM WINK/WNOG.