Not known to transmit any human or animal pathogens.

This species is not known to have any associated organisms.

Traps should be spaced 26-33 ft. apart, placed at a height of 3 to 5 feet above host plants, and raised as the crop grows. 

This trap is also known as the unitrap. The trap has a green canopy, yellow funnel, and white bucket and is used with a dry kill strip. For instructions on using the trap, see the Plastic Bucket Trap Protocol. 

Mesh screens are now available for purchase through IPHIS survey supply. Product name: Plastic Bucket Traps, Mesh Screen.

Attaching lures to traps

IMPORTANT: Do not include lures for other target species in the trap when surveying for this target.

Note: Visual surveys for damage or larvae are not an approved method and cannot be used to report negative data, but we are including some visual guidance to help surveyors who may observe larvae or signs of infestation. 

In all hosts: Larvae are defoliators. They will make holes in leaves and eventually skeletonize them. They start feeding on older leaves and then move on to younger leaves. During outbreaks, high larval populations may also target the hearts (e.g., lettuce hearts, beet taproots) of plants and leaf-stalks.

In certain host plants, distinct signs other than defoliation may appear. In artichoke, Autographa gamma larvae may feed on the flower heads (the edible portion of the plant), causing injured, twisted, or perforated bracts. In grape, larvae can feed on the fruit skin, leading to rotten and spoiled bunches; one larva can damage >20 ripe grapes. In iceberg lettuce, larvae tend to burrow 2-3 leaves into the head, so they are not easy to observe.

A Likelihood of Establishment Map is now available. This survey should only be considered in the states with appropriate conditions and suitable hosts for this moth. The map was produced by the SAFARIS Team. SAFARIS is a modeling framework that enables PPQ to quickly respond to emergencies, efficiently survey for pests, and assess potential pest impacts by collecting critical geospatial data and developing predictive models. SAFARIS is developed and maintained by the NC State University, Center for Integrated Pest Management (CIPM) with support from PPQ PERAL. The SAFARIS team used a likelihood of establishment model for silver Y moth occurrence in the continental United States, that was developed by PPQ PERAL and NCSU CIPM, to support CAPS survey planning. The model predicts the suitability of an area for silver Y moth occurrence based on the likelihood of favorable conditions for the moth occurring using tools and data within SAFARIS. The detailed method used in this assessment is described here.

Surveys should take place at the start of spring and continue through the fall.

Pheromone trapping surveys are the approved method. 

Traps should be placed along the field edges of host crops, as previous studies have captured moths in these areas. Traps should be suspended from stakes and placed at a height of 5 ft. above host plants and raised as the crop grows. 

This species has a large host range. Surveys can occur in any area that has host material, including field crops, greenhouses, and nurseries. Economically important crops that this pest has damaged include alfalfa, artichoke, basil, brassicas (e.g., cabbage, cauliflower, collards, brussels sprouts, and kale), chicory, flax, hazelnut, hemp, grape, hops, lettuce, peas, rape, rapeseed, solanaceous crops (e.g., eggplant, pepper, potato, tomato), soybean, spinach, strawberry, sugar beet, tobacco. Emphasis should be on high hazard areas (e.g., near warehouses that receive cargo from countries where A. gamma is known to occur, the northeast US, etc.) and fields with host material near a port having a history of interceptions. 

• Autographa gamma - Silver Y Moth, Field Screening Aid by Brambila and Passoa
  • A field screening aid for A. gamma, including a brief description of some of the common non-target Plusiinae found in traps.
• Autographa gamma - Silver Y Moth, Identification Aid
  • An identification aid displaying the various genitalic features necessary to identify A. gamma.
• Eichlin, T.D. and Cunningham, H.B., 1978. The Plusiinae (Lepidoptera: Noctuidae) of America north of Mexico, emphasizing genitalic and larval morphology. United States Department of Agriculture, Agricultural Research Service, Washington, DC, 122 pp.
  • This book has a key to the genera of three tribes of Plusiinae adults and key to the Plusiinae species present in North America. Last accessed December 9, 2025.
• Lafontaine, J. D. and R. W. Poole. 1991. The moths of America north of Mexico (MONA), Noctuoidea, Noctuidae (Part), Plusiinae. Fascicle 25.1, 182 p.
  • This is a more recent revision of Eichlin and Cunningham, 1978. Last accessed December 9, 2025.

Autographa gamma is very similar to several North American species in the subfamily Plusiinae. Some of these can be distinguished by external morphology characteristics, while others will require dissection of genitalia. The wing color of A. gamma is not distinctive, and final identification requires examination of male genitalia. It is best to consult a specialist before attempting to dissect genitalia.

Autographa californica and A. pseudogamma share similar wing coloration and a distinct silver shining mark ('stigma') in a "Y" shape on the forewings with A. gamma. Therefore, genitalia examination is needed to correctly identify them. Autographa californica is a polyphagous pest of vegetables, forage crops, and legume crops, including peas, alfalfa, and clover while A. pseudogamma is reported from hardwood and conifer forests; no other host information is available. Autographa californica occurs in the eastern United States and the Midwest but is especially common in the western United States. The range of A. pseudogamma is Canada, New England and the western United States. It is absent from most of the Midwest and the southern United States. Both species can be found throughout the Pacific Northwest, but A. pseudogamma is mostly found at high elevations. Surveys in the western United States should expect more suspects needing genitalic dissection or barcoding. Numbers of A. californica in the eastern and midwestern states should be smaller and A. pseudogamma should be largely absent.

Trichoplusia ni can often be separated from A. gamma by forewings that lack contrasting bands or areas of different colors. The stigma is usually composed of a solid dot and a u-shaped portion that may be fused together. Because the wing coloration and the shape of the marks are variable, it may be necessary to dissect the genitalia for a correct identification. Both species feed on a wide range of plants, but like A. gamma, T. ni prefers brassicas. Trichoplusia ni can be found throughout most of the United States.

Autographa ampla and Anagrapha falcifera both have a solid, contrasting rectangular shaped marking in the middle of the lower margin of the forewing. This marking is absent, or diffuse if present, in A. gamma. On the forewing, the stigma of most specimens of A. falcifera and A. ampla have a thin white extension that touches part of the rectangular marking. The stigma of A. gamma has no extension. Both of these species can be found in most areas of the United States.

Ctenoplusia oxygramma, the 'sharp stigma looper', has a stigma that is characteristically solid, elongated, and comes to a point in the middle of the wing. This mark can aid in distinguishing it from A. gamma. Ctenoplusia oxygramma occurs most commonly in the eastern and midwestern states.

Rachiplusia ou resembles A. gamma, but it can be identified by the presence of setae that look like spines on the tibia of all three pairs of legs by an experienced identifier or by dissection of genitalia. Along with A. californica, it is the species most likely to be confused with A. gamma in traps. It is widespread over the central, eastern, and southern United States.

Chrysodeixis chalcites is also included in the National Priority Pest List. It has been detected in Michigan, Indiana, Pennsylvania, and Illinois, but is not known to be established in the United States. It is similar in size and appearance to A. gamma but can be differentiated by forewings which are gold to bronze, and while it has silver marks in the forewings as in A. gamma, these marks are more oval in shape. Chrysodeixis chalcites is present in southern Europe, the Mediterranean region, Africa, and in east central Canada (Ontario).

Chrysodeixis includens differs from A. gamma in having a metallic bronze sheen on the forewing. This coloration is absent in A. gamma. The middle of the forewing fringe often has a black spot in C. includens. Chrysodeixis includens is present across the continental United States, but is most common in the southern and eastern United States.

See the CAPS Pest Datasheet for images.