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Silver Y Moth

Autographa gamma

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Silver Y moth adult
Silver Y moth showing the wing patterns and color and the distinctive "y". Photo: Paolo Mazzei, Bugwood.org
Silver Y moth larva
Silver Y moth larva feeding on a leaf. Photo: Paolo Mazzei, Bugwood.org
Preserved silver Y moth specimen
Preserved silver Y moth specimen. Photo: Julieta Brambila, USDA APHIS PPQ, Bugwood.org
 

Originally from the United Kingdom, the silver Y moth has steadily spread across the globe. With large populations in Europe, Asia, and Africa, it is clear that the silver Y moth is capable of not only surviving, but thriving in an array of different climates. Approximately 50% of the United States' climates would be suitable environments for the silver Y moth. The caterpillars feed on plants that grow low to the ground, most often potatoes, cabbage, tomatoes, alfalfa, lettuce, and other common row crops.

Concern

Most interceptions containing this moth have been at JFK International Airport in cargo destined for New York State. Since the silver Y moth feeds on plants close to the ground, the market for many crops grown in New York would be severely threatened by the introduction of this pest, including alfalfa, arugula, beet, cabbage & other Brassicas, carnation, carrot, Chrysanthemum, corn, elderberry, flax, geranium, grapevine, bean, lettuce, onion, pea, pepper, potato, soybean, sunflower, and wheat. Upon the moth's arrival, affected areas could potentially be quarantined, making it impossible for farms in those areas to sell their produce locally and abroad. Silver Y moths are strong fliers and can migrate in both southerly and northerly directions.

Description

The silver Y moth has intricate wing patterns, varying from one individual to another, comprised of brown, grey, beige, deep purple and brassy hues. Wing pattern and color depend on the climate in which the larvae grow. A medium sized moth, it has a wingspan of 1.2 to 1.6 inches. The silver Y moth has several generations per year; the adults of the early spring generation are usually smaller and more grey-brown in color, while those of the later generations are generally larger with darker wing patterns. The defining trait of these moths, regardless of generation, is the creamy, silver "Y" in the center of each forewing. The alfalfa looper, found primarily in Western North America, looks very similar to silver Y moth, and it is nearly impossible to tell the two apart on appearance alone. Although they fly most often at night, the silver Y moth can fly during the day, typically in overcast conditions.

Damage

Crop damage is caused by silver Y moth larvae. Female moths lay their eggs on the underside of leaves of the low-growing plants they target. When the larvae emerge, they feed on the plant's leaves, often consuming the plant entirely. Adults feed on the nectar from the fruit and flowers of host plants with their coiled tongues.

For More Information

Silver Y Moth, Invasive Species of the Month. February 2011. Oregon Invasive Species Council.

Authored by Juliet Carroll and Kelsey Peterson, New York State Integrated Pest Management Program, Cornell University