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February 2011- Silver Y Moth
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Article Content
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| Invasive Species of the month |
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Photo credit to Julieta Brambila USDA APHIS PPQ
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Invasive Species of the month Silver Y Moth- (Autographa gamma)
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| What? |
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The Silver Y moth is named after the distinctive markings on its wings that looks like the letter y or Greek letter (Gamme). The Silver Y is a medium sized moth with a wingspan of 30 to 40 mm. The wings are intricately patterned with various shades of brown and gray, providing excellent camouflage. There are several different forms with varying colors depending on the climate in which the larvae grow. This pest feeds on more than 200 different plant species, many of which are either low growing weeds or commonly cultivated crops. Notable host plants include alfalfa/ Lucerne, alpine lady fern, artichoke, geranium, grapevine, green bean/ dry edible bean, leek, lettuce, onion, parsley, pea, pepper, potato, purple clover, radish, spinach, sugar beets, sunflower, tomato, wheat and zinnia. Damage is done by the larva. Early instars feed on the underside of the leaf, scraping “window” between the veins. Later instars chew right through the leaf, usually leaving main vein intact. On tomato and beans, larvae chew into green fruit. Over 50 percent of the leaf surface may be destroyed, but there is some evidence that the actively growing parts of the host plant are not readily attacked.
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| Where? |
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The species is widespread across Europe, parts of Asia, and North Africa. In spring, the moths migrate north reaching as far as Iceland, Greenland, and Finland with huge invasions taking place in some years. A second wave of migrants arrives in the summer. In central Europe and the British Isles adults are present in significant numbers from May onwards with numbers dwindling in late autumn as they are killed off by frosts. Some individuals fly south again to winter around the Mediterranean and Black Seas. The Silver Y moth occurs in a wide variety of habitats, particularly open areas. It regularly visits gardens to take nectar from flowers
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| Lookalike? |
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In Oregon the Silver Y moth can be confused with a closely related native noctuid moth, the alfalfa looper, Autigrapha california. For final identification, a specialist needs to dissect and examine the male genitalia.
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| What can you do? |
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Be on the lookout for this moth, and please report suspected invaders online at http://oregoninvasiveshotline.org/ or call the Invasive Species Hotline at 1-866-INVADER (1-866-468-2337), this number is toll free.
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