Ficus Leaf-rolling Psyllid | Pest Rating Proposals and Final Ratings

California Pest Rating for

Trioza brevigenae Mathur: Ficus Leaf-rolling Psyllid

Hemiptera: Triozidae

Pest Rating: B

PEST RATING PROFILE

Initiating Event:

On August 10, 2016 Dr. Alessandra Rung identified a sample of psyllids collected in Carson (Los Angeles County) as Trioza brevigenae, Ficus leaf-rolling psyllid. On August 25, 2016 USDA National Identification Services confirmed this as a new record for the Western Hemisphere. A pest rating proposal is required to determine a permanent pest rating.

History & Status:

Background: Trioza brevigenae is only known to feed on new leaves of curtain fig (Ficus microcarpa). Feeding causes a distinctive, tight leaf roll. Trioza brevigenae may be transported long distances when infested plants or fresh plant parts are moved.

Worldwide Distribution: Trioza brevigenae is native to India. California is the first other location in which it has been reported.

Official Control: Trioza brevigenae is not known to be under official control in any other states or nations.

California Distribution: Trioza brevigenae has been confirmed from Los Angeles County. There are also reports of the psyllid from Orange, Ventura, San Diego, Riverside, and San Bernardino Counties.

California Interceptions: Trioza brevigenae is not known to have ever been intercepted in California.

The risk Trioza brevigenae (Ficus leaf-rolling psyllid) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Ficus microcarpa is a popular ornamental that grows in USDA plant hardiness zones 9-11, corresponding with much of the San Joaquin Valley, Coastal, and Southern California. Trioza brevigenae is expected to be able to establish throughout these regions wherever suitable host plants are found. 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: Trioza brevigenae is only known to feed on curtain fig (Ficus microcarpa). It receives a Low (1) 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: Psyllids have high reproductive rates and can disperse locally by flying. They may also be transported long distances when infested plants or leaves are moved or by hitchhiking on clothing, equipment, or animals. Trioza brevigenae 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: Ficus microcarpa plants are a valuable component of the nursery industry. However, Trioza brevigenae has already established a widespread distribution in Southern California and there have been no reports of economic impacts. It is likely that existing nursery practices for other Ficus microcarpa pests are limiting impacts from this new one. Due to the absence of this psyllid from the entirety of North America there could be disruptions to markets for California produced Ficus microcarpa nursery stock. Trioza brevigenae receives a Low (1) 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: Trioza brevigenae is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. It is not likely to affect threatened or endangered species or disrupt critical habitats. It may trigger new treatment programs by residents who find highly infested landscape plants unacceptable. Ficus microcarpa trees are widely grown as ornamentals in California and are likely to be significantly impacted by this pest. Trioza brevigenae 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 Trioza brevigenae (Ficus leaf-curling psyllind): 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: Trioza brevigenae has been confirmed from Los Angeles County and is also reported to be widespread across southern California. It receives a Medium (-2) 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: Medium (9)

Uncertainty:

There have not been any recent surveys for this psyllid in other parts of California, so it may be more widespread. Over the last three years many new Ficus pests have been found in southern California including ficus whitefly (Singhiella simplex), ficus eye-spot midge (Horidiplosis ficifolii), Cuban-laurel thrips (Gynaikothrips uzeli), and curtain fig psyllid (Macrohomotoma gladiata). It is possible that new treatments that are already necessary for these other new pests will preclude some of the economic and environmental impacts from additional new pests such as Trioza brevigenae. Alternatively, the psyllid might have a larger host range in California than has been documented elsewhere.

Conclusion and Rating Justification:

Trioza brevigenae is considered to be widespread in southern California and is likely to have significant economic and environmental impacts as it expands its range to other parts of the state. A “B” rating is justified.

References:

¹ Hodel, Donald R., Gevork Arakelian, Linda M. Ohara, Cheryl Wilen, and Surendra K. Dara. 2016. The Ficus Leaf-Rolling Psyllid: A New Pest of Ficus microcarpa. PalmArbor 2016-2: 1-9. http://ucanr.edu/sites/HodelPalmsTrees/files/242336.pdf

² Hodel, Donald R., Gevork Arakelian, Linda M. Ohara, Surendra K. Dara, and Cheryl Wilen. 2016. Ficus leaf-rolling psyllid, Trioza brevigenae: a new pest of Ficus microcarpa in southern California. UC ANR Pest News. http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=21788

³ Dara, Surendra K. 2016. A new psyllid pest on ornamental trees in California. Entomology today. https://entomologytoday.org/2016/08/23/a-new-psyllid-pest-on-ornamental-trees-in-california/

⁴ Ficus Tree Encounters New Pest. American Nurseryman. http://www.amerinursery.com/pest-management/ficus-tree-encounters-new-pest/