Onions, Garlic: Onion thrips
categories: Onions, Garlic Onions, Garlic Insects Vegetables
last review date: 2025-04-16 07:35
Photo by: Unknown
Biology
Onion thrips are tiny, slender insects about 1⁄16″ long. They are yellowish to dark in color, depending on age. They feed on tender inner leaves, causing longitudinal silvery to white mottling or streaking along the leaves. Often, tiny black specks of frass (excrement) may be present. The mottled areas later turn yellow or brown. Damaged leaves may wither and droop. Severe damage may kill seedlings and reduce yield. Thrips are also found on debris of the host plants and on weeds.
Management Options
See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.
Non-chemical Management
Select non-chemical management options as your first choice!
- Heavy rain or sprinkler irrigation may help control thrips populations.
- Control weeds in and around the garden.
- Remove piles of plant debris, particularly culled onion bulbs and tops.
- Natural enemies including predacious thrips help control populations of plant-feeding thrips. Avoid use of broad-spectrum insecticides which kill beneficial insects.
Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.
- Apply to green onion according to label instructions when thrips or early damage is first observed.
- Soaps may require several applications.
Approved Pesticides
Examples of pesticides that are legal for home use in Washington State are listed below.
The list may not include all products registered for this use.
WSU Extension programs and employment are available to all without discrimination.
Evidence of noncompliance may be reported through your local Extension office.