False Trochanter Mealybug | Pseudococcus dolichomelos | Pest Rating Proposals and Final Ratings

California Pest Rating for

False Trochanter Mealybug | Pseudococcus dolichomelos Gimpel and Miller

Hemiptera: Pseudococcidae

Pest Rating: A

PEST RATING PROFILE

Initiating Event:

Pseudococcus dolichomelos is currently Q-rated. A permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background: This mealybug is found underground on the roots and crown of its host plants (Gimpel and Miller, 1996). It presumably feeds on roots. It has been associated with plants in at least 12 families: Amaryllidaceae, Asteraceae, Euphorbiaceae, Fabaceae, Hypericaceae, Onagraceae, Poaceae, Polygonaceae, Rosaceae, Solanaceae, Urticaceae, and Zingiberaceae (García Morales et al., 2016). The biology of this recently-described (1996) species is poorly known.

Worldwide Distribution: Pseudococcus dolichomelos occurs in the eastern United States (Florida, Louisiana, Maryland, Michigan, New York, North Carolina, South Carolina, Texas, Utah, Washington, D.C., and West Virginia) and Hawaii (García Morales et al., 2016; Gimpel and Miller, 1996; von Ellenrieder and Watson, 2016).

Official Control: Pseudococcus dolichomelos does not appear to be under official control anywhere.

California Distribution: Pseudococcus dolichomelos is not known to occur in California (Symbiota Collections of Arthropods Network).

California Interceptions: Pseudococcus dolichomelos has been intercepted in California associated with cut flowers of Alpinia purpurata, Oncidium sp., and Zingiber sp. from Hawaii (PDR # 1367825, 1367535, 070P06137999, and 100P06282530), peaches from Utah (PDR # TR0P06024371), and primrose plants from Florida (PDR # 370P06678226).

The risk Pseudococcus dolichomelos would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Pseudococcus dolichomelos occurs over a wide portion of the United States, including areas with temperate (e.g., Michigan) as well as tropical/subtropical (e.g., Hawaii, south Texas) climates. This suggests that this species is capable of becoming established over a wide portion of California. It has been associated with a wide variety of plants in 12 families, so it is not expected to be limited by distribution of potential host plants. Therefore, Pseudococcus dolichomelos receives a High (3) in this category.

– 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: Pseudococcus dolichomelos has been associated with, and presumably feeds on at least 12 families of plants. Therefore, it receives a High (3) in this category.

– 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: Pseudococcus dolichomelos has been intercepted multiple times on cut flowers and other commodities, so it is evidently capable of being spread artificially on infested plants. Therefore, it receives a Medium (2) in this category.

– 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: Root-feeding mealybugs include species that are pests of food and ornamental plants. However, dolichomelos is not known to be an economic pest anywhere it is known to occur, even though it occurs over a wide area. Therefore, it receives a Low (1) in this category.

Economic Impact:

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: 1

– 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: Root-feeding mealybugs have the potential to impact the health of plants, as demonstrated by the fact that some are economically-significant pests. If Psuedococcus dolichomelos became established in California, it would encounter species of native plants, including many rare ones, that it has not previously been exposed to. It is possible that it could have an impact of some of these plants. Therefore, it receives a Medium (2) in this category.

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

Environmental Impact: A

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.

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 Pseudococcus dolichomelos: Medium (11)

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: Pseudococcus dolichomelos is not known to occur in California. It receives a Not established (0) in this category.

–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:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (11)

Uncertainty:

The most important uncertainty regarding this species is its ability to significantly impact the health of plants; this has not been shown to be the case anywhere it currently occurs.

Conclusion and Rating Justification:

Pseudococcus dolichomelos is a root-feeding mealybug with a broad host range. It is not known to occur in California, but it is likely capable of becoming established over a large portion of the state. If this was to occur, it is not likely to become an economic pest, but there is a chance that it could impact the environment. For these reasons, an “A” rating is justified.

References:

García Morales, M., Denno, B.D., Miller, D.R., Miller, G.L., Ben-Dov, Y., and Hardy, N.B. 2016. ScaleNet: A literature-based model of scale insect biology and systematics. Accessed November 7, 2017. http://scalenet.info.

Gimpel, W. F. and Miller, D.R. 1996. Systematic analysis of the mealybugs in the Pseudococcus maritimus complex (Homoptera: Pseudococcidae). In (B.K. Gupta, ed.) Contributions on Entomology, International (pp. 38-42). Associated Publishers. Gainesville, Florida. 163 pp.

Symbiota Collections of Arthropods Network. Accessed March 7, 2018. http://scan1.acis.ufl.edu

von Ellenrieder, N., and Watson, G. 2016. A new mealybug in the genus Pseudococcus Westwood (Hemiptera: Coccomorpha: Pseudococcidae) from North America, with a key to species of Pseudococcus from the New World. Zootaxa. 4105: 65-87.

Author:

Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741, plant.health[@]cdfa.ca.gov

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211, plant.health[@]cdfa.ca.gov

Comment Period:* CLOSED

4/10/18 – 5/25/18

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