Ferrisia dasylirii (Cockerell): Mealybug

California Pest Rating for

Ferrisia dasylirii (Cockerell): Mealybug

Hemiptera: Pseudococcidae

Pest Rating: C

PEST RATING PROFILE

Initiating Event:

From 1953 to 2012, Ferrisia dasylirii was incorrectly considered a synonym of B-rated Ferrisia virgata. A recent revision corrected this and resurrected F. dasylirii as a valid species¹. On August 28, 2014 Dr. Gillian Watson notified me that she had examined specimens in the California State Collection of Arthropods and confirmed that F. dasylirii is present in the state. Because this mealybug is not on CDFA’s pest rating list, a pest rating proposal is needed to determine future direction.

History & Status:

Background: Ferrisia dasylirii is a polyphagous mealybug that feeds on a wide variety of plants, including many ornamentals and some crops. It may be spread long distances by commerce in infested plants or plant products.

Worldwide Distribution: Ferrisia dasylirii appears to be of Neotropical origin. It is found from the United States south to Chile². It is also found in Hawaii and several Caribbean islands².

Official Control: Ferrisia virgata is considered a quarantine pest by Israel, Japan, and New Zealand³. It is likely that these trading partners will also consider the newly resurrected F. dasylirii as a quarantine pest if it is intercepted.

California Distribution: Specimens of Ferrisia dasylirii in the state collection indicate that the mealybug is present in the environment of Alameda County (1962), Imperial County (1993, 2003), Los Angeles County (2000), San Bernardino County (1978, 1979, 1982), San Diego County (1978), and San Joaquin County (1980, 1995).

California Interceptions: From August 19, 2014 to August 26, 2015 Ferrisia dasylirii was intercepted 24 times by California’s high risk programs and dog teams on fruit and plants shipped from Florida, Hawaii, Michigan, Mississippi, and within California.

The risk Ferrisia dasylirii would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Ferrisia dasylirii is polyphagous and suitable host plants are grown throughout California. 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: Ferrisia dasylirii feeds on a wide variety of plants in at least 29 families². 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: Mealybugs reproduce rapidly and can spread locally by crawling or by wind. They may move long distances rapidly by hitchhiking on clothing, animals, or equipment or by the movement of infested plants or plant products. Ferrisia dasylirii 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: Ferrisia dasylirii has been present in California since at least 1962 and has not emerged as a significant pest. Several trading partners might consider this mealybug to be a quarantine pest and its presence on plants or plant products could have trade impacts. No other economic impacts are expected. Ferrisia dasylirii 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: Ferrisia dasylirii has been present in California since at least 1962 and has not had significant economic impacts. It receives a Low(1) 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 Ferrisia dasylirii: 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: Records in the state collection indicate that Ferrisia dasylirii is widespread in the environment of California. The mealybug receives a High(-3) 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: Low(8)

Uncertainty:

There is significant genetic variability within Ferrisia dasylirii¹. It is possible that some lineages could be cryptic species that are not present in California.

Conclusion and Rating Justification:

Ferrisia dasylirii is widespread in the environment and is not having significant economic or environmental impacts. A “C” rating is justified.

References:

¹Kaydan, M.B. and P.J. Gullan. 2012. A taxonomic revision of the mealybug genus Ferrisia Fullaway (Hemiptera: Pseudococcidae), with descriptions of eight new species and a new genus. Zootaxa 3543: 1-65. http://www.mapress.com/zootaxa/list/2012/3543.html

²SEL Catalog. http://www.sel.barc.usda.gov/catalogs/pseudoco/Ferrisiadasylirii.htm

³USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). https://pcit.aphis.usda.gov/pcit/