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Dendrothrips ornatus

Damage caused by privet thrips feeding. Photo: Whitney Cranshaw, Colorado State University, Bugwood.
Scientific Name: 
Dendrothrips ornatus
Common Name: 
Privet Thrips
Growing Degree Days (GDD's): 
192–618 GDD's; 1029–1266 GDD's, Base 50F, March 1st Start Date (Source: Cornell Cooperative Extension and Robert Childs, UMass Extension.)
Host Plant(s) Common Name (Scientific Name): 
Ash (Fraxinus spp.)
California privet (Ligustrum ovalifolium)
Lilac (Syringa spp.)
Privet (Ligustrum spp.)
Regel privet (Ligustrum obtusifolium 'Regel')
Insect Description: 

The life history and biology of the privet thrips is not completely understood. Adult females lay their eggs on host plant leaves late in the spring, with several generations per year possible through the summer. The number of generations on a single plant may depend upon the food quality of the plant for the thrips following so many generations of feeding. Immature thrips (larvae) are slender and wingless and found with magnification primarily on leaf undersides. Adults are also tiny, 1 mm in length, with wings. The larvae and adults feed and cause chlorosis on host plant leaves, which may be visible to the naked eye as a dusty/gray color. When populations are high, 20-30 privet thrips may be found per leaf. Adult privet thrips are active fliers. Note that the word "thrips" refers to both the singular and plural of the insect. The privet thrips is non-native to North America, and was introduced. This insect is native to parts of Europe, Asia, and Russia.

Damage to Host: 

Leaves and twigs of privet are fed upon by the privet thrips. Attacked leaves will appear grayish in color, made up of chlorotic spots. Immature (nymphal) thrips are found on the underside of the foliage. Magnification is required to view the insect. Pests of nursery and greenhouse production.


Scout for graying or chlorotic leaves and visually inspect for long, tiny insects. Magnification will be required to help view them. Check leaf undersides. Visual scouting can occur regularly through the growing season in nursery production, and is aided by tapping symptomatic material over a white sheet of paper or placing blue or yellow sticky cards near plants. Search for the insects on paper or sticky cards.

Cultural Management: 

Sanitation can help in certain circumstances to reduce thrips activity. This may be particularly helpful in nursery settings. Remove weeds, old planting materials and debris, and keep the area clean. Screening can also help exclude insects from greenhouses. Screens less than 0.88 mm. may be necessary to exclude thrips, but make sure the small screen size isn't impacting airflow quality in these settings.

Natural Enemies & Biological Control: 

Predators, nematodes, and entomopathogenic fungi have been used to successfully manage certain species of thrips, particularly in greenhouse production. These methods are understood for western flower thrips and chilli thrips, but the efficacy of the different species of natural enemies available for use on privet thrips may not be currently fully understood.

Chemical Management: 

Abamectin (NL)

Acephate (NL)

Acetamiprid (L)

Azadirachtin (NL)

Beauveria bassiana (NL)

Bifenthrin (NL)

Carbaryl (L)

Chlorpyrifos (N)

Chromobacterium subtsugae (NL)

Clothianidin (NL)

Cyantraniliprole (NL)

Cyfluthrin (NL)

Dinotefuran (NL)

Fenpropathrin (NL)

Flonicamid+cyclaniliprole (N)

Tau-fluvalinate (NL)

Gamma-cyhalothrin (L)

Lambda-cyhalothrin (L)

Malathion (L)

Metarhizium anisopliae (robertii) (NL)

Neem oil (NL)

Pyrethrin+sulfur (NL)

Spinetoram+sulfoxaflor (N)

Spinosad (NL)


While imidacloprid products are often labelled for thrips management, and are registered for use in Massachusetts, this active ingredient may not be the best option for managing thrips. Unlike dinotefuran (another neonicotinoid), imidacloprid often does not provide satisfactory results when used to manage thrips. For example, some research suggests that imidacloprid causes insecticide resistance and resurgence in western flower thrips post application (Cao et al., 2019).

Active ingredients that may be applied systemically include: abamectin (injection), acephate (injection), acetamiprid (injection), azadirachtin (injection, soil drench), clothianidin (soil drench), cyantraniliprole (soil drench, soil injection), dinotefuran (soil drench), Metarhizium anisopliae (robertii) (soil drench), and neem oil (soil drench).

When used in a nursery setting, chlorpyrifos is for quarantine use only.

Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.

Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.

Read and follow all label instructions for safety and proper use. If this guide contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Read the full disclaimer. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: January 2024. To check current product registrations in Massachusetts, please visit: .