Spodoptera eridania (Stoll): Southern Armyworm
Pest Rating: A
PEST RATING PROFILE
Researchers recently applied for a USDA permit to import 60,000 eggs and larvae of Spodoptera eridania into California for field research. Florida reports that this moth is already found in California and of no consequence here1. A pest rating proposal is required to support the current pest rating.
History & Status:
Background: Spodoptera eridania is a polyphagous noctuid moth that feeds on the foliage, fruit, and flowers of a variety of plants1,2. Adults and larvae are nocturnal. Young larvae typically feed in groups on the undersides of leaves. They often skeletonize leaves and can occasionally defoliate entire plants1,2. As they mature they become solitary and readily bore into fruit1. If food is scarce they will consume branches, stem tissue, and tubers near the surface of the soil1. Agricultural crops that are damaged by the moth include avocado, beet, cabbage, carrot, citrus, collard, cowpea, eggplant, okra, peanut, pepper, potato, sunflower, sweet potato, tobacco, velvet bean, watermelon, and many ornamentals1. The caterpillars also feed on many weeds but show a preference for pigweed (Amaranthus spp.) and pokeweed (Phytolacca americana)1. Populations of the caterpillars sometimes build up in weedy areas then migrate to adjacent crops after favored weeds are consumed1. The moth typically pupates in soil. Spodoptera eridania is commonly intercepted in Europe on plants and tomato fruit2. The moth is also a popular organism for research because it is easy to rear2 and has the potential to be spread long distances by researchers.
Worldwide Distribution: Spodoptera eridania is native to North, Central, and South America including the eastern United States as far north as Massachusets and as west as Texas1,2. The only place it is known to have invaded is the Galapagos Islands2.
Official Control: Spodoptera eridania is listed as a harmful organism by Albania, Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Holy See (Vatican City State), Honduras, Hungary, India, Ireland, Israel, Italy, Japan, the Republic of Korea, Latvia, Lithuania, Luxembourg, Malta, Monaco, Montenegro, Morocco, Netherlands, Norway, Panama, Poland, Portugal, Romania, Russian Federation, San Marino, Serbia, Slovakia, Slovenia, Spain, Svalbard and Jan Mayen, Sweden, Switzerland, Taiwan, Turkey, and the United Kingdom3. The moth is listed as an A1 quarantine pest by the EPPO2. In addition, all species of Spodoptera are listed as harmful organisms by Antigua and Barbuda, Bermuda, Japan, and Panama3.
California Distribution: Spodoptera eridania has never been found in the environment of California.
California Interceptions: Spodoptera eridania has only been intercepted four times by CDFA on bell peppers, cilantro, tree fern, and Asparagus sperengeri from Florida. There have been 859 interceptions identified as Spodoptera sp. Some of these interceptions could also be Spodoptera eridania.
The risk Spodoptera eridania (southern armyworm) would pose to California is evaluated below.
Consequences of Introduction:
1) Climate/Host Interaction: Spodoptera eridania is widespread across regions with a wide variety of climates. Southern armyworm would be likely to establish a widespread distribution in California and 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: Spodoptera eridania is a generalist feeder on a wide variety of plants and 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: Spodoptera eridania can complete a generation every 30-40 days under favorable conditions and each female lays a large number of eggs. Adult moths may disperse locally by flying and caterpillars may crawl in large numbers to areas with better host plants. Southern armyworm may also be transported long distances on infested plants or fresh plant parts or by scientists. 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: Although it is usually only a minor pest, southern armyworm does sometimes have damaging infestations to crops, especially tomatoes2. Southern armyworm caterpillars may disfigure nursery stock with feeding damage and pupate in the associated soil, reducing the value of nursery stock. Infestations do sometimes trigger treatments, which increase crop production costs. Spodoptera eridania is listed as a harmful organism and quarantine pest by many nations and has the potential to disrupt markets for California’s fresh fruit and nursery stock. Southern armyworm receives a High (3) 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: Spodoptera eridania is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes. It is not expected to affect threatened or endangered species or disrupt critical habitats. It may trigger new treatment programs in agriculture and by residents. It may also significantly affect many plants that are popular in home/urban gardens and ornamentals. Southern armyworm 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 Spodoptera eridania (Southern Armyworm): High (15)
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: Spodoptera eridania 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: High (15)
Unidentified life stages of Spodoptera are frequently intercepted by CDFA. Presumably they go undetected at other times and enter the state. There have not been any recent formal surveys for Spodoptera eridania in California and it could be established in some localities.
Conclusion and Rating Justification:
Spodoptera eridania has not been found in California and it is likely to have significant economic and environmental impacts if it were to establish in the state. An “A” rating is justified.
1 Capinera, John L. 2014. University of Florida Featured Creatures. Common name: southern armyworm. http://entnemdept.ufl.edu/creatures/veg/leaf/southern_armyworm.htm
2 EPPO Data Sheets on Quarantine Pests: Spodoptera eridania. http://www.eppo.int/QUARANTINE/insects/Spodoptera_eridania/PRODER_ds.pdf
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: A
Posted by ls