California Pest Rating for
Quadrastichus erythrinae Kim: Erythrina gall wasp
Pest Rating: B
PEST RATING PROFILE
In April 2015 the United States Department of Agriculture (USDA) released a Deregulation Evaluation of Established Pests (DEEP) report that proposed to change the status of Quadrastichus erythrinae to non-actionable. A pest rating proposal is required to determine future direction on this pest in California.
History & Status:
Background: Quadrastichus erythrinae is an emerging pest gall wasp that disfigures the leaves and young shoots of more than 60 species of coral trees (Erythrinia spp.)1,2. It may be transported long distances when infested plants or plant parts such as fallen leaves are moved1. Female wasps insert eggs inside young leaves and stem tissue1. As larvae develop, they induce galls which cause leaves to curl and shoots to become swollen1. Larvae pupate inside leaves and stems and adults chew their way out as they emerge1. Heavy infestations can cause defoliation and death of trees1. Quadrastichus erythrinae was first found in Hawaii in 2005 and within 2 years caused 95% mortality of Erythrina trees1.
Worldwide Distribution: Quadrastichus erythrinae is believed to be native to Africa1. From there it has spread through much of Asia and the Pacific islands including Hawaii1. In the Americas it is established in Brazil, Guadeloupe, Martinique, and Florida1.
Official Control: Quadrastichus erythrinae is listed as a harmful organism by China, but is not known to be under official control in any other states or nations3.
California Distribution: Quadrastichus erythrinae has never been found in the environment of California.
California Interceptions: Quadrastichus erythrinae has never been intercepted in California.
The risk Quadrastichus erythrinae (Erythrina gall wasp) would pose to California is evaluated below.
Consequences of Introduction:
1) Climate/Host Interaction: The current distribution of Quadrastichus erythrinae corresponds to USDA Plant Hardiness Zones 10-13. This indicates that the pest is likely to be limited to the warmest parts of southern California. Quadrastichus erythrinae receives a Low (1) 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: Quadrastichus erythrinae is only known to feed on coral trees in the genus Erythrina. 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: Quadrastichus erythrinae has a high reproductive rate. Each female carries an average of 320 eggs and can complete a life cycle in 20 days1. These gall wasps may be transported long distances when infested plants or plant parts are moved and disperse locally by flying, wind, or by hitchhiking on clothing, animals, or equipment1. Quadrastichus erythrinae 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: If Quadrastichus erythrinae were to establish in California it is not expected to lower any crop yields. It may reduce the value of Erythrina nursery stock and increase production costs of those trees. The gall wasp is not expected to disrupt any markets, change cultural practices, vector other organisms, injure animals, or interfere with water supplies. Quadrastichus erythrinae 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: Quadrastichus erythrinae is not expected to lower biodiversity, disrupt natural communities, or change ecosystem practices. It is not likely 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 wish to save their coral trees. Coral trees are grown as ornamentals in southern California and may be extirpated by Quadrastichus erythrinae. Erythrina gall wasp 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 Quadrastichus erythrinae (Erythrina gall wasp): Medium (9)
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: Quadrastichus erythrinae has never been found in California 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.
–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: Medium (9)
There have not been any surveys for Quadrastichus erythrinae in California.
Conclusion and Rating Justification:
Quadrastichus erythrinae has never been found in California. However, if it were to establish in the state its effects are likely to be limited to coral trees in the nursery industry and southern California landscape. A “B” rating is justified.
1 CABI Invasive Species Compendium. Datasheet on Quadrastichus erythrinae (Erythrina gall wasp). http://www.cabi.org/isc/datasheet/46220
2 Baez, Ignacio. DEEP Report Quadrastichus erythrinae Kim: Erythrina gall wasp. Deregulation Evaluation of Established Pests (DEEP). Plant Epidemiology and Risk Analysis Lab. Center for Plant Health Science and Technology.
3 USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). https://pcit.aphis.usda.gov/pcit/
Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211, plant.health[@]cdfa.ca.gov.
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Pest Rating: B
Posted by ls