Onions · Symptom guide
Bugs on onion plants
Bugs on onion plants in a garden bed are a look-and-compare job. Cited sheets list onion maggot as observations, not a ranked or confirmed cause. This page does not diagnose, name a spray, or sell a treatment.
Cited observations are comparisons—not a confirmed diagnosis. Check the cited sources and local requirements before taking action.
Save this bed. See it coming next year.
Your checks stay in the Field Book so next season is not a guess.
Illustrative photograph — not identification proof.
Look
Compare the plant in front of you with the cited notes after Other causes. Yellow leaves or wilt alone do not name a cause on this page.
Other causes
Growing notes live on how to grow onions. Garden-wide looks live on garden pests. Tomato hornworm is a separate species page — not this crop-pest list.
What the sources say — at a glance
One source per card. Facts are not averaged.
Clemson HGIC 1314 (South Carolina)
Onion maggot named on onions. Feeds on the bulbs.
Details and limits (3)
Look
Clemson HGIC 1314 (South Carolina) names onion maggot on onions. Naming on that sheet — not a ranking and not a diagnosis.
Look
Clemson HGIC 1314 (South Carolina): the onion maggot feeds on the bulbs. Onion maggots are attracted to decomposing organic matter. Observation on their onion sheet — not a diagnosis.
Limit
South Carolina HGIC 1314. Naming-on-sheet and observation only.
Maryland Extension (Maryland)
Cream-colored, legless, 1/3 in. Allium family. Wilt or turn yellow. Row cover. Pull and destroy.
Details and limits (6)
Look
Maryland Extension (Maryland): the larvae are cream-colored, legless, and 1/3 inch long. Observation — not a diagnosis.
Host
Maryland Extension (Maryland): this is a common pest of allium family members. Host as named — not a ranking.
Look
Maryland Extension (Maryland): infested plants wilt or turn yellow and die. Observation — not a diagnosis.
Method
Maryland Extension (Maryland): where this insect has been a problem, use row cover. Method — not a prevention promise.
Method
Maryland Extension (Maryland): pull and destroy affected plants. Method — not an efficacy claim.
Limit
Maryland wireworms-and-maggots sheet. Observation, host, and method as named.
Illinois Extension (Illinois)
Above 40 degrees north latitude. Roots of onion plants.
Details and limits (2)
Look
Illinois Extension (Illinois): above 40 degrees north latitude, root maggots may attack the roots of onion plants. Observation — not a diagnosis.
Limit
Illinois onion page. Observation only.
UMN Extension (Minnesota)
Bores into plant stems. Yellow and wilt.
Details and limits (2)
Look
UMN Extension (Minnesota): onion maggot bores into plant stems, causing the plants to turn yellow and wilt. Observation on their onion sheet — not a diagnosis.
Limit
Minnesota growing-onions page. Observation only.
Sources differ
Make it yours
Save the bed in the Field Book so next season is not a guess.
How we know — methodology. Ranges and assertions are cited per source, not blended.