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Basil, rosemary and other aromatic herbs vs aphids: does it work?
Sources (0)
Promising Some peer-reviewed or extension evidence, but limited, conditional or mixed.
Lab and small field studies show some aromatic herbs reduce host attractiveness to aphids, but garden-level pest control is not well demonstrated.
Mechanism
Odor masking and repellency (e.g., terpenoids like alpha-pinene from rosemary).
What the research found
- The Ben-Issa et al. (2017) review lists studies where basil, rosemary and lavender reduced attractiveness of pepper to green peach aphid, and summer savory with basil repelled black bean aphid.
- Rosemary odor compounds masked host-plant odors for onion aphid in olfactory tests (same review).
Caveats
Much evidence is from olfactometers or small plots. Effects are short-range.
How to try it
Fine to mix herbs into beds; don't rely on them alone.
Other Promising pairings (4)
- French marigold as a cover crop for root-knot nematodes
- Collards as a trap crop for diamondback moth in cabbage
- White clover living mulch under cabbage and other brassicas
- Carrots and onions against carrot fly
Evidence summary checked 2026-10-14. We cite only peer-reviewed studies, university extension and USDA/ARS sources; results may differ in your region. Not professional advice.