Chrysodeixis chalcites (Esper): Golden twin-spot moth

California Pest Rating for
Chrysodeixis chalcites (Esper): Golden twin-spot moth
Lepidoptera: Noctuidae
Pest Rating: A

Initiating Event:

May 6, 2015 the United States Department of Agriculture’s New Pest Advisory Group (NPAG) distributed a one-page notice highlighting the risk posed by Chrysodeixis chalcites.  A pest rating proposal is required to support its permanent pest rating.

History & Status:

BackgroundChrysodeixis chalcites is a highly polyphagous moth whose caterpillars primarily feed on foliage but may feed externally on fruit and internally in legumes1.  In many countries it is considered one of the most important Lepidopteran pests2.  It is an important pest of alfalfa, clover, corn, soybean, artichokes, tomato, sweet pepper, potato, other greenhouse and field fruits and vegetables, and ornamental plants2.  Eggs are typically deposited one or two at a time on the leaves of host plants1.  First instar larvae feed on the lower leaf surface1.  Later instars web leaves together and skeletonize them before consuming entire leaves1.  The last instar usually pupates on the underside of a leaf with folded edges but may pupate on fruit1 or in soil2.  Partial host lists have been compiled by NPAG, CAPS, and CABIChrysodeixis chalcites is capable of long migratory flights and may be transported when infested plants or fresh plant parts are moved.

Worldwide Distribution: Chrysodeixis chalcites is widespread in Africa, the Middle East, India, and the Mediterranean2.  Aided by wind it migrates to northern Europe2.  It has been present in Ontario, Canada since 2008.  The moth has also been found in greenhouses in Ohio, Colorado, Louisiana, North Carolina, and Oregon2.  CDFA’s interception records indicate the moth may also be present in Hawaii and New York.

Official Control: Chrysodeixis chalcites is listed as a harmful organism by Colombia, Costa Rica, Japan, and the Republic of Korea4.

California DistributionChrysodeixis chalcites has not been found in the environment of California.

California InterceptionsChrysodeixis chalcites has been intercepted by CDFA 84 times.  Interceptions have occurred on fresh herbs (oregano, basil, thyme, marjoram, saluyot, and ti leaves), cut flowers, and plants shipped from New York and Hawaii.  At least some of these consignments originated in Israel.  The moth was also found in one nursery inspection in Fresno County in 1990 (PDR 909394).

The risk Chrysodeixis chalcites (golden twin-spot moth) would pose to California is evaluated below.

Consequences of Introduction:  

1) Climate/Host Interaction: Chrysodeixis chalcites has established and is widespread in latitudes between 45˚N and 35˚S. This encompasses all of California and the moth is expected to be capable of establishing a widespread distribution in the state.  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: Chrysodeixis chalcites is highly polyphagous 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: Each female Chrysodeixis chalcites can lay up to 1,060 eggs1.  The moths breed continuously throughout the year with 8 to 9 generations per year in Egypt1.  They are strong migratory fliers1 and may also spread long distances when infested plants, fruit, or soil are moved.  Chrysodeixis chalcites 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: Chrysodeixis chalcites is likely to reduce crop yields in California.  The caterpillars feed on the leaves and fruit of tomato and may reduce yield 10-15%2.  It is expected to lower the value of fruit and nursery stock by feeding damage and contaminating it with its presence.  Several of California’s trading partners list the moth as a harmful organism so there could be disruptions to fresh fruit, cut flower, and nursery stock exports.  Chrysodeixis chalcites 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: Chrysodeixis chalcites is not expected to lower biodiversity, disrupt natural communities, or change ecosystem processes.  It may feed on threatened and endangered species such as showy Indian clover (Trifolium amoenum), Pacific Grove clover (Trifolium polyodon), and Monterey clover (Trifolium trichocalyx).  The moth is not expected to disrupt critical habitats.  It may trigger new chemical treatment programs in agriculture and by residents who find defoliation unacceptable.  Chrysodeixis chalcites 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 Chrysodeixis chalcites (Golden Twin-Spot Moth):  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: Chrysodeixis chalcites 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.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: High (15)


 Differentiation of Chrysodeixis chalcites and Chrysodeixis eriosoma requires molecular analysis.  It is possible that Chrysodeixis chalcites could be established in some states where Chrysodeixis eriosoma is established.  There have been no recent surveys for this pest in California so it might be present in some localities.

Conclusion and Rating Justification:

Chrysodeixis chalcites has not been found in California and is expected to have significant economic and environmental impacts if it establishes in the state.  An “A” rating is justified.


1 Millar, Leah. 2013. NPAG Report Chrysodeixis chalcites (Esper): Goldwn twin-spot moth, tomato looper.

2 CAPS Factsheet Chrysodeixis chalcites.

3 CABI Invasive Species Compendium.  Datasheet: Chrysodeixis chalcites (golden twin-spot moth).

4 USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD).

Responsible Party:

Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211,[@]

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Pest Rating: A

Posted by ls