Pezothrips kellyanus (Bagnall): Kelly’s Citrus Thrips

California Pest Rating for
Pezothrips kellyanus (Bagnall): Kelly’s Citrus Thrips
Thysanoptera: Thripidae
Pest Rating: A

Initiating Event:

In May 2015 Pezothrips kellyanus was intercepted by CDFA’s high risk programs on three shipments of leis from Hawaii.  A pest rating proposal is required to assign a permanent pest rating.

History & Status:

Background:  Larvae and adult Pezothrips kellyanus feed on flowers, young leaves, and fruit1.  Where it is established it may be the most common thrips in citrus orchards3 and is considered to be a serious pest2.  Pupae overwinter in the soil and leaf litter and adults migrate to flowers as they emerge in the spring3.  Adult females lay eggs inside the tissue of flowers, fruits, and leaves2. Primary hosts are: Rutaceae: Citrus bergamia2 (bergamot orange), Citrus aurantium2 (orange), Citrus limonia2 (lemon), Citrus spp.3; Caprifoliaceae: Lonicera spp.2 (honeysuckle), Oleaceae: Jasminum fruticans2 (wild jasmine), Pittosporaceae: Pittosporum tobira2 (Japanese mock-orange).  Other hosts include: Anacardiaceae: Mangifera indica3 (mango); Apiaceae: Daucus carota (Queen Anne’s lace), Foeniculum vulgare2 (fennel); Apocynaceae: Araujia sericifera5 (moth plant); Asteraceae: Helianthus spp. (sunflower), Senecio spp.2 (ragworts), Anthemis cotula2 (stinking chamomile), Leucanthemum vulgare2 (ox-eye daisy), Sonchus oleraceus2 (common sowthistle), Calendula arvensis3 (field marigold), Urospermum picroides3 (prickly goldenfleece); Brassicaceae: Brassica spp.2 (mustard), Brassica rapa sylvestris2 (wild turnip), Sinaspis alba2 (white mustard); Fabaceae: Trifolium repens2 (white clover), Trifolium pratense2 (red clover); Lauraceae: Persea americana (avocado); Malvaceae: Malva nicaeensis3 (bull mallow), Malva sylvestris3 (common mallow); Oleaceae: Jasminum officinale3 (jasmine); Jasminum sambac3 (Arabian jasmine), Ligustrum vulgare2 (wild privet); Oxalidaceae: Oxalis pes-caprae3 (Bermuda buttercup); Pittosporaceae: Hymenosporum sp.1 (native frangipani); Rosaceae: Eriobotrya japonica3 (loquat); Prunus dulcis (almond)3; Rubus fruticosus2 (blackberry); Rubiaceae: Gardenia jasminoides3 (gardenia); Solanaceae: Lycopersicon spp.2 (tomato).  Pezothrips kellyanus may be transported long distances when infested plants, fresh plant parts, or soil or leaf litter is moved.

Worldwide Distribution: Pezothrips kellyanus is probably native to Australia1.  From there it has spread to New Zealand1, New Caledonia1, France1, Italy1, Greece1, Cyprus1, Turkey1, Spain2, Portugal2, and Israel2.  Recent interceptions indicate that it could be present in Hawaii.

Official Control: Pezothrips kellyanus is listed as a harmful organism by Chile and Japan4.

California Distribution:  Pezothrips kellyanus has never been found in the environment of California.

California Interceptions:  From 2001 and 2015 Pezothrips kellyanus has been intercepted by CDFA 13 times on shipments of leis from Hawaii.

The risk Pezothrips kellyanus (Kelly’s Citrus Thrips) would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Pezothrips kellyanus is established in areas with climates similar to California and is expected to encounter suitable host material throughout much of the state. It receives a High (3) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California.  Score:

Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Pezothrips kellyanus is polyphagous on plants in at least 15 families.  It receives a High (3) in this category.

Evaluate the host range of the pest. Score:

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

3) Pest Dispersal Potential: Pezothrips kellyanus has a high reproductive rate and may breed continuously throughout the year on plants that have extended flowering periods and repeated flower flushes2, such as lemons.  The thrips may spread long distances when infested plants, fresh plant parts, or soil and leaf litter are moved.  It may also spread by hitchhiking on clothing, equipment, or animals.  Pezothrips kellyanus receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

Low (1) does not have high reproductive or dispersal potential.

Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

4) Economic Impact: If Pezothrips kellyanus were to establish in California it may lower crop yields and lower crop value.  It is considered a serious pest in citrus orchards and its feeding can lead to reduced yields and disfigure fruit with stem-end scarring, ring-scarring with halo and scurfing, and rind discoloration2,5.  This may lead to fresh market fruit being diverted to juice production and trigger chemical treatments2.  There are many additional crops in California that may also be affected.  The presence of this thrips in California may also disrupt markets since it is listed as a harmful organism by both Japan and Chile4Pezothrips kellyanus is not expected to change cultural practices, injure animals, or disrupt water supplies.  It is not known as a vector of plan pathogens.  It receives a High (3) in this category.

Evaluate the economic impact of the pest to California using the criteria below. Score:

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Low (1) causes 0 or 1 of these impacts.

Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

5) Environmental Impact: If Pezothrips kellyanus were to establish in California it is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes.  It may feed on threatened and endangered species including Algodones Dunes sunflower (Helianthus niveus tephrodes), showy indian clover (Trifolium amoenum), pacific grove clover (Trifolium polyodon), and Monterey clover (Trifolium trichocalyx).  The thrips is not expected to disrupt critical habitats.  It is likely to trigger new chemical treatments in agriculture and by residents who find infested plants unsightly.  Many of the hosts of Pezothrips kellyanus are grown as ornamentals and in home gardens in California and may be significantly impacted.  Pezothrips kellyanus receives a High (3) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact. Score:

Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Pezothrips kellyanus (Kelly’s Citrus Thrips): High (15)

Add up the total score and include it here.

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Pezothrips kellyanus has never been found in California and receives a Not established (0) in this category.

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

Not established (0) Pest never detected in California, or known only from incursions.

Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: High (15)


Existing IPM programs targeting other thrips that are already established in California may preclude some of the impacts from this pest.

 Conclusion and Rating Justification:

Pezothrips kellyanus has never been found in California and may have significant economic and environmental impacts if it were to establish in the state.  An “A” rating is justified.


1 Hoddle MS, Mound LA, Paris DL. 2012. Thrips of California. CBIT Publishing, Queensland.

2 Marullo, Rita. EPPO Quarantine Bulletin.  Università degli Studi di Reggio Calabria,d.cGU&cad=rja

3 Vassiliou, V.A. 2010. Ecology and behavior of Pezothrips kellyanus (Thysanoptera: Thripidae) on citrus.  Journal of Economic Entomology 103(1):47-53.

4 USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD).

5 Navarro-Campos, Cristina, Apostolos Peskas, Amparo Aguilar, and Ferran Garcia Mari. 2013. Factors influencing citrus fruit scarring by Pezothrips kellyanus.  Journal of Pest Science

Responsible Party:

Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211,[@]

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Pest Rating: A

Posted by ls