California Pest Rating for
Ophelimus maskelli (Ashmead): Eucalyptus Gall Wasp
Pest Rating: C
PEST RATING PROFILE
Ophelimus maskelli has been found in the environment of southern California and is presently assigned a temporary rating of “Q”. A pest rating proposal is required to assign a permanent pest rating.
History & Status:
Background: Ophelimus maskelli is a species of wasp that induces galls on leaves of several species of Eucalyptus. Uncontrolled populations can cause severe leaf damage and early leaf drop1.
Worldwide Distribution: Ophelimus maskelli is probably native to Australia. It was first found in the Mediterranean basin in Italy in 1999 and has since spread around the region1. It has also been found in New Zealand, Indonesia, South Africa, and Vietnam1. Ophelimus maskelli may be transported long distances when infested plants or fresh plant parts are moved.
Official Control: Ophelimus maskelli is not known to be under official control in any other states or nations.
California Distribution: Ophelimus maskelli is found in the environment of Riverside, San Diego, and Orange County1. It is likely present in Los Angeles County.
California Interceptions: Ophelimus maskelli has been found in one nursery in Riverside County (PDR 331P06142763).
The risk Ophelimus maskelli (Eucalyptus gall wasp) would pose to California is evaluated below.
Consequences of Introduction:
1) Climate/Host Interaction: Eucalyptus trees are commonly planted as ornamentals in southern and coastal California. Ophelimus maskelli is likely to establish wherever suitable hosts are found. It receives a Medium (2) 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: Ophelimus maskelli is only known to feed on the leaves of Eucalyptus trees. 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: Ophelimus maskelli can build large populations quickly, indicating high reproductive potential. It may be transported long distances in infested plants or fresh plant parts. It 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: Ophelimus maskelli is not expected to lower any crop yields. It may lower the value of Eucalyptus nursery stock by disfiguring plants with its presence. It is not expected to disrupt markets, change cultural practices, vector other organisms, or injure animals. Ophelimus maskelli 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: Ophelimus maskelli is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. It is not expected to directly affect threatened or endangered species or disrupt critical habitats. It may trigger additional treatment programs in the nursery industry and by residents who find infested plants unsightly. Eucalyptus trees are common ornamentals and can be defoliated by this wasp. Ophelimus maskelli 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 Ophelimus maskelli (Eucalyptus gall wasp): Medium (10)
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: Ophelimus maskelli is established in Riverside, San Diego, and Orange counties1. It is probably also present in Los Angeles County. 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.
The final score is the consequences of introduction score minus the post entry distribution and survey information score: Low (8)
Ophelimus maskelli was widespread and abundant in southern California when it was first observed. It is likely much more widespread.
Conclusion and Rating Justification:
Ophelimus maskelli is widespread and abundant in the environment of southern California and is not under official control. Impacts are expected to be limited to disfigurement of Eucalyptus trees and possible increased insecticide use. A “C” rating is justified.
1 Burks, Roger A., Jason L. Mottern, Rebeccah Waterworth, and Timothy D. Paine. 2015. First report of the Eucalyptus gall wasp, Ophelimus maskelli (Hymenoptera: Eulophidae), an invasive pest on Eucalyptus, from the Western Hemisphere. Zootaxa 3926(3): 448-450.
Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211, plant.health[@]cdfa.ca.gov.
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Pest Rating: C
Posted by ls