Onion thrips movement into celery: Scout now and rotate insecticides

Zsofia Szendrei<szendrei@msu.edu>, Michigan State University Extension - July 21, 2026

As onion fields mature, onion thrips may leave those fields and move into nearby celery. At this time of the season, celery fields, particularly those located near onion fields, require increased scouting as onion harvest approaches.

green celery with light green markings throughout and dirt on the roots — This celery was next to an early variety of onions. As the onions matured, thrips moved in, rasping the petioles. Photo by Ben Werling, MSU Extension.

Resistance management must extend across crops

Onion thrips moving into celery in late July through August should not be viewed as a new, previously untreated population. Depending on the neighboring onion field’s spray history, migrating thrips may already have been exposed to one or more insecticide groups before arriving in celery. Applying an insecticide with the same mode of action immediately after migration could continue that selection pressure.

When possible, consider insecticide use in nearby onion fields when selecting the first celery treatment. Rotate to an effective IRAC group that was not used recently against thrips in the onions. This is especially important because some active ingredients or related modes of action are used in both crops.

Within celery, continue rotating among effective IRAC groups and avoid treating successive thrips generations with the same mode of action.

Several insecticides have thrips listed specifically in their celery section; their effectiveness ranges from control to suppression. Example trade names are provided in the table; this list does not imply endorsement of any particular brand.

Active ingredient	Example trade name	IRAC group	Thrips in celery	Other pests
Spinetoram	Radiant SC	5	Control	Caterpillars
Spinosad	Entrust SC	5	Control	Caterpillars
Tolfenpyrad	Torac	21A	Control	Aphids
Cyantraniliprole	Exirel	28	Suppression	Caterpillars
Cyantraniliprole + abamectin	Minecto Pro	28 + 6	Suppression	Green peach aphid control, Caterpillars
Spirotetramat	Movento	23	Western flower thrips larvae suppression	Aphids

Products that control thrips

Spinetoram (Radiant SC), spinosad (Entrust SC) and tolfenpyrad (Torac) are labeled for thrips control in celery. Radiant and Entrust are both IRAC Group 5 insecticides. Switching between them does not constitute rotation to a different mode of action. Entrust is approved for use in organic production when used in accordance with organic certification requirements, but its mode of action is closely related to that of Radiant.

Torac is an IRAC Group 21A contact insecticide and provides another mode of action for a thrips-control program. It also controls aphids in celery. The celery directions list a rate of 21 fluid ounces per acre for thrips. Because Torac works primarily through contact, adequate water volume and thorough coverage of protected plant surfaces are important.

Products labeled for thrips suppression

Cyantraniliprole (Exirel) and the combination of cyantraniliprole plus abamectin (Minecto Pro) list suppression of foliage-feeding thrips rather than control. These products should be used while populations are low rather than as rescue treatments against a severe infestation.

Exirel is an IRAC Group 28 insecticide. Minecto Pro contains both a Group 28 and a Group 6 active ingredient. Because both products contain cyantraniliprole, applying Minecto Pro after Exirel does not provide a rotation away from Group 28.

Spirotetramat (Movento) is primarily useful in celery as a systemic aphid treatment. Its thrips claim is limited to suppression of western flower thrips larvae. Movento is most effective against developing populations and requires sufficient healthy foliage for uptake and movement within the plant.

Consider the other pests present

The pest complex in a field can help determine which product is the best fit. Torac provides control of both thrips and aphids. Exirel provides aphid activity and thrips suppression, while Minecto Pro controls green peach aphid and suppresses foliage-feeding thrips. Movento controls aphids while suppressing western flower thrips larvae.

Radiant and Entrust do not list aphids in their celery directions, although both provide activity against several caterpillar pests. Exirel and Minecto Pro also control several labeled caterpillar pests in celery.

None of the products in the table lists leafhoppers in its celery section. If leafhoppers are the primary concern, pyrethroids could be effective (but will not control thrips). If a selective material is desired, flupyradifurone (Sivanto Prime) is labeled for leafhopper and aphid control in celery, but it does not have a celery-thrips claim.

Importance of scouting

Thorough coverage is especially important because thrips feed in protected plant tissue. Continue scouting after an application to determine whether populations are declining and whether another treatment is justified. Selecting a product based on the pests actually present will help avoid unnecessary applications and preserve effective insecticides.

Reference to commercial products or trade names does not imply endorsement by Michigan State University Extension or bias against those not mentioned.

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