Category Archives: Acari

Peacock Mite | Tuckerella sp

California Pest Rating for
Peacock Mite | Tuckerella sp.
Acari: Tuckerellidae
Pest Rating: A



Initiating Event:

Tuckerella sp. (Peacock mite) was intercepted in June 2017 by San Joaquin county dog team on a shipment of Mango fruits (Magnifera indica) originating in Miami, Florida ( PDR# 570P6611570)  and again in July 2017 by Sacramento county dog team from a shipment of mamey sapote (Pouteria sapota) fruits originating in Puerto Rico (PDR# 570P06611782) . This species has temporary rating of “Q”.  A pest rating proposal is required to determine a permanent pest rating.

History & Status:

Background: Tuckerella spp. are significant herbivorous pests in the tropics on citrus fruit. They are called peacock mites because of the peacock tail of plumose posterior setae that trails out behind them. Their dorsal shields are covered with large, leaf like setae. These setae are swept over the body to deter predators (Walter 2009).

Tuckerellids are slow moving, typically bright red and occur in soil and in stems, leaves and fruit of plants. Described species of Tuckerella fall into two species groups that segregate ecologically. One group is found in association with grasses (perhaps feeding on roots) and the other on stems and fruits of woody plants. Some species of the latter group are pests of citrus (Walter 2009)

Worldwide DistributionTuckerella spp. have limited distribution worldwide. Half of the spp. are reported from eastern Asia. T. ornata (Tucker), T. pavoniformus (Ewing) and T. knorri Baker and Tuttle are originally described from South Africa, Hawaii and Thailand respectively and are each reported from several continents (Manual of Acarology 2009).

Official Control: Two Tuckerella sp. are considered harmful organisms. Tuckerella. flabellifera and T. japonica are reported as harmful organisms in the Republic of Korea and Japan respectively (PCIT 2016).

California Distribution: Tuckerella spp. have never been found in the natural environment of California.

California Interceptions: Tuckerella spp. have been intercepted five times between July, 2011 and July, 2017 by CDFA at various border stations during inspection of vehicles entering California.

The risk Tuckerella sp. (Peacock mite) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Tuckerella are mainly found in the tropics and have been reported occurring in soils and in association with underground plant parts. However, T. hypoterra has been collected from pasture soil in South Dakota and T. colegynis from foliage and debris in Nevada (Krantz 2009). Depending on the species, Tuckerella spp. might establish a widespread distribution in California and receives a High (3) in this category

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

Score: 3

– 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: Tuckerelilids are considered pests of ornamentals and fruit crops in the United States. Peacock mite cause damage to citrus, avocado, tea and other ornamental and fruit crops (Ochoa, 2010). These crops are widely cultivated in California. It receives a High (3) in this category

Evaluate the host range of the pest:

Score: 3

– 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: Tuckerlilid mites have a high reproduction rate, several reproduction modes and short life cycles. Peacock mites have 5-7 pairs of caudal setae that help with their wind borne dispersal (The full wiki, 2010). Mites are very small and small populations are not easily detectable during visual inspection. This allows them to be rapidly transported long distance when infested plants or fresh plant material is moved. Peacock mite receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest:

Score: 3

– 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: Peacock mite was recorded in Central America as a pest of citrus plants and fruits but it has never been associated with serious damage to citrus. Tuckerella knorri has been reported as a serious pest of citrus in Costa Rica and is likely to reduce yields. It is reported to occur in association with the fungus Sphaceloma fawceti which is considered a causative agent of the cracking of citrus fruits (Vacante 2010). It receives a Medium (2) in this category.

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

Economic Impact: A, E

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.

Economic Impact Score: 2

– 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: Tuckerella are not likely to lower the biodiversity and disrupt natural communities. Since mites can be contaminants of stored grains and phytoparasites of several crops, its infestations could cause private treatment by homeowners. It receives a Medium (2) in this category.

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

Environmental Impact: A, E

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 sp..

C. The pest could impact threatened or endangered sp. 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:

Environmental Impact Score: 2

– 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 Tuckerella sp. (peacock mite): High (13)

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: Tuckerella has never been found in the environment 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:

Score: 0

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 (13)


Peacock mites have been intercepted a few times by CDFA for many years. Some Tuckerella spp. like T. pavoniformis do not cause economic damage to citrus but other sp. like T. knorri can damage citrus plants and fruits. Even though Tuckerella spp. have not been found in natural environment of California, they can resemble California native mites like citrus bud mite and Texas citrus mite. If Tuckerella spp. are introduced to California, they might have the potential to cause significant economic damage to citrus growing areas of the state. There have not been any formal surveys done to confirm the presence of Tuckerella spp. in California on crops like Citrus and avocado. Early surveys can confirm the presence of Tuckerella spp. in California.

Conclusion and Rating Justification:

Tuckerella sp. has never been found in the environment of California and might have significant economic and environmental impacts if it were to enter the state. An “A”-rating is justified.


 Krantz G.W. 2009. A manual of Acarology, 3rd edition, pp 302

Ochoa R., Aguilar H., and Vargas C. 1994. Phytophagous mites in Central America: an illustrated guide

Ochoa, Ronald-Ron. 2010. Mite Systematics and Arthropod Diagnostics with Emphasis on Invasive sp.. USDA ARS Systematic Entomology Laboratory, Beltsville, MD 

Ochoa, Ronald. The genus Tuckerella in Costa Rica (Acari: Tuckerllidae). International Journal of Acarology. 14 (2): 205-207

The Full Wiki. 2010. Tuckerella Encyclopedia

Vacante, Vincenzo. 2010. Review of the phytophagous mites collected on Citrus in the world. Acarologia 50 (2): 221-241.

Walter, David Evans; Proctor, Heather (2013). Mites: Ecology, Evolution & Behavior. Springer Science & Business Media. p. 292. ISBN 978-94-007-7164-2.


Raj Randhawa, 1220 ‘N’ Street, Room 221, Sacramento CA 95814, (916) 403-6617,[@]

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211,[@]

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4/11/18 – 5/26/18


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Pest Rating: A


Posted by ls