By Joey Slowik
Today, I’d like to talk about the Delicate Silver Y moth, Autographa pseudogamma. This medium sized moth is in the family Noctuidae. This family includes many pest species of cutworms and is well represented in Alaska, but this moth’s caterpillar is not a cutworm. They have five similar looking instars — phases between the caterpillars’ molting periods. The last instar will grow to about an inch, and is usually bright green with a noticeable lateral white line along their back. Early instars will also have several dorsal white lines.
The caterpillars are aboveground feeders and will select a wide variety of plants from dandelion to alfalfa. They are voracious feeders and it only takes a few days of feeding between each molt. They can go from egg to pupa in 20 days and will spend another 10-12 days pupating before emerging as an adult moth.
The adult moths are cool looking. They have the usual body plan for a noctuid species with a fluffy head area, brown-grey in color and generally triangular-shaped when resting. Near the center of each forewing, there are two noticeable comma-shaped white marks. Hair tufts that almost appear as if the moth has a mohawk help it disappear when resting in a clump of dead leaves, or tree bark. Because they are nocturnal, remaining hidden during the day is crucial.
The adults will be out June through August. Based on when we see adult moths, the eggs likely overwinter near a host plant, a strategy used by many insects to get through the winter. Next summer, keep a close eye out for these insects. If you want to see one now, check the garage —you may be lucky enough to find a dried-out adult who was trying to hide out for the winter.
Joey Slowik, IPM Technician, jaslowik@alaska.edu
