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How long do systemic Bonide granules make a plant toxic to humans #892328
Asked February 05, 2025, 12:38 PM EST
Hello, I mistakenly applied systemic Bonide insecticide granules not for edible plants to a small citrus tree (calamondin) that I keep as a houseplant. I'm wondering if fruit from this tree is now poison forever, or if there's a time frame after which the systemic will no longer be dangerous to humans. The active ingredient is imidacloprid 0.22%
I applied approximately 3 tablespoons of granules to approximately 5 gallons of soil (less than the recommended 2.5 tablespoons per gallon). The tree's trunk is about 1 inch in diameter.
I applied the granules 5 weeks ago. According to the instructions, the systemic is supposed to be effective against pests for up to 8 weeks, but for how long does it make the plant toxic after that? Where does systemic insecticide become most concentrated? In the trunk, leaves, or fruit?
There were about a half dozen immature fruits on the tree when I applied the granules 5 weeks ago, and they are now starting to ripen. Is it possible those fruit would be safe to eat if they are ripe in another three weeks? What about fruit that grows in the future?
I'm hoping you can provide some info about whether I've effectively ruined our fruit tree forever, or if there is a chance it'll be safe to eat its fruit in the future.
Thanks very much for your time.
Best,
Susan
Montezuma County Colorado
Expert Response
Hi Susan,
I don't have a specific answer for you right now but have some resources to find a better answer.
Here is an information sheet on the active ingredient from the National Pesticide Information Center https://npic.orst.edu/factsheets/imidagen.html
A specific timeline of when the fruit could be safe isn't listed in any of the safety data sheets or from the information sheet I linked. I'd recommend calling NPIC <personal data hidden> or emailing them at <personal data hidden>. They are open from 8:00AM to 12:00PM Pacific Time, Mon-Fri. If you need me to follow up with them, let me know.
What I can tell you is the imidacloprid 0.22% is taken up into the plant so it would be found on the leaves but I don't have confirmation of how it would be take up into citrus fruit. What I do see is that other formulations are approved for citrus but I'm not finding recommendations related to when the insecticide is applied (with fruit present vs. not).
Sorry I don't have an exact answer but I hope NPIC is helpful. If you have further questions for me reach out at <personal data hidden> or<personal data hidden>
Best,
Emily Lockard