Garden pest
Onion thrips
Silvery streaks and curled leaf tips that show up in hot spells.
Onion thrips is in its active season now — scout your plants this week.
How to identify onion thrips
Thrips are tiny pale slivers, barely a speck to the naked eye, that hide in the tight folds and necks of onion and garlic leaves. You usually see the damage long before you see the bug.
Tap a leaf over a sheet of white paper and the specks that crawl and scatter are thrips. They breed fastest in hot, dry weather.
Attacks: Onions, Garlic, Leeks, Cabbage
Life cycle: Thrips complete a generation in as little as two weeks in warm weather, so numbers explode through the summer heat; they overwinter in plant debris and weeds and move in as the season warms.
Signs of onion thrips
What you actually see on the plant — usually before you spot the pest itself.
- Silvery or whitish streaking and fine stippling along the leaves
- Curled or distorted leaf tips, worst in hot dry weather
- Whole plantings looking bleached and set back during a heat wave
- Tiny dark specks (thrips and their droppings) down in the leaf folds
Organic control, least-toxic first
Start at the top and only move down if you need to. Physical and cultural fixes come before any spray.
- Knock them back with overhead water
Thrips hate being wet. A regular overhead spray or watering washes them off and breaks up the dry conditions they thrive in, which alone keeps light infestations in check.
- Hang blue sticky traps
Blue sticky cards set among the plants catch flying adults, both thinning the population and telling you when numbers are rising so you can act early.
- Spray insecticidal soap, spinosad, or neem
For a real outbreak, a registered insecticidal soap, spinosad, or neem oil hits thrips on contact. Spray into the leaf folds where they hide, reapply on the label's schedule, and treat in early morning or evening to protect bees. Follow the product label for rate and timing.
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One rule for any product you spray: follow the label. The label is the law, and it is the tested, safe rate for your plants — homemade mixes and dish-soap sprays are not, and can scorch foliage.
Prevent it next season
- Water consistently in hot spells so plants are not stressed and thrips are washed off
- Clear weeds and old debris where thrips overwinter and shelter
- Hang blue sticky traps early to catch the first wave before it builds
Questions about onion thrips
What causes silvery streaks on my onion leaves?+
Thrips. These tiny sap-raspers scrape the leaf surface, leaving silvery or whitish streaking and stippling that gets worse in hot, dry weather.
How do I get rid of thrips on onions?+
Start with overhead watering to wash them off, hang blue sticky traps to catch adults, and for heavy outbreaks spray a registered insecticidal soap, spinosad, or neem into the leaf folds, following the label.
Plan a garden that fights back
Healthy, well-spaced plants shrug off pests that flatten a crowded bed. PlotToTable sizes your beds, spaces every crop, and flags the pests that hit what you grow.