Natter’s Notes

Noctua pronuba, the Winter Cutworm

Jean R. Natter, OSU Master Gardener

Fig 1: Common mullein, Verbascum thapsus, with numerous holes, most likely caused by the winter cutworm. (J. R. Natter; 2019-04-14)

Winter cutworms, also known as Large Yellow Underwings, were first identified in Oregon about 2001. Since then, they have raised a ruckus in home gardens, lawns, pastures, and agricultural fields during the winter. The larvae (caterpillars) feed on a wide array of plants at night, whenever the air temperature is 40F or more. So, it’s critical that the damage is differentiated from that of slugs and snails which, by the way, don’t always leave a slime trail.

ID characteristics

Both the adult and larvae are seen in several color forms. Among the adults (moths), the wing coloration ranges from light tan to quite dark brown. But certain characteristics are constant, among them the 2 dark, kidney-shaped spots on each forewing.

To ID the larvae (caterpillars), look for a brown, inverted-Y on a light-colored head capsule. And, along each side of the body, you’ll see a row of dark dashes, each one underlined with a slightly shorter, light colored dash. Newly molted caterpillars are bright green. And, as is usual for Lepidoptera, the larvae will also have prolegs and 3 pair of true legs.

Life cycle

Fig 2: Newly molted winter cutworm, 2 inches long (J R. Natter; 2010-04)

During the growing season, the adults rest in the shelter of leaves on low-growing plants. Now and then, it’s likely you’ll flush one out while working in the garden during the summer.

The flash of orange on each hind wing of a brown moth is an easy field ID character. (See

The life cycle follows complete metamorphosis. The several hundred eggs are laid in large patches on the host plant, arranged in neat side-by-side rows. Larvae (caterpillars) hatch in 2 to 4 weeks. They’ll feed in the fall and continue through the winter, at night, whenever the temperatures are above 40F. During the day, the larvae rest just under the soil surface, quite close to the stem of the victimized plant.

Because caterpillars are chewing pests, plant parts disappear. Winter cutworms commonly align with leaf edges and eat inward, creating larges scallops. Or they may chow down somewhere within the leaf blade.

The caterpillars pupate in the soil. Likely you’ll find a number of them as you prepare your flower and veggie beds this spring. A fun project is to rear out the pupae to verify which particular caterpillar species you have.

To rear a pupa, place it in clear container and cover with a breathable lid, perhaps paper toweling held in place with a rubber band. Set the container somewhere you’ll see it often, but not in the sun, then wait for the adult to emerge. Adult moths are always easier to ID than are pupal cases you find in soil.

Common victims

Favored host plants are numerous, among them flowers and vegetables; Pacific coast iris; and the great common mullein, Verbascum thapsus, the latter considered a weed here in Oregon. During 2015, they specialized in “mowing” grasses at their bases.


Because damage occurs during winter, be certain to differentiate damage from that caused by slugs and snails which, by the way, don’t always leave a slime trail. Then, too, before you suggest treatment, determine if damage is current and possibly ongoing. Or is it old damage? In that case, the pest is long gone.


The PNW Insect Management Handbook discusses home garden management of caterpillars in the section Horticultural, Landscape, and Ornamental Crops: Common Landscape Pests.

Take your choice of physical methods, among them to handpick; feed to the birds, drop into a nearby spider web; flick into soapy water; cut in half or stomp. Bacillus thuringiensis (Bt) is an organic ingredient useful against caterpillars on both ornamental and edible plants; always apply according to label directions.


  1. Large Yellow Underwing A New Cutworm in Idaho includes images of several very similar species, most of which are more common in agricultural sites than in home gardens;
  2. Winter Cutworm: A New Pest Threat in Oregon contains close-up views of the larvae [page 3] as well as chemical recommendations for both home and commercial users;
  3. Large Yellow Underwing moth and cutworm caterpillar, Noctua pronuba has excellent images of eggs, larvae, pupae, and adults;

PDF Version Noctua pronuba

By Margaret Bayne, OSU Extension Staff-retired, OSU Master Gardener

May 2019

Photo: Lynn Ketchum, OSU

Liver, colon cancer cells thwarted by compounds derived from hops. (Adrian Gombart, via Steve Lundeberg, OSU)

Sticky science: Evolution of spider webs.  “The eight-legged weavers have been hunting insects for almost 400 million years, flaunting their long history in a rich array of architectures. Scientists are still figuring out the taxonomy of them all.” (Lindzi Wessel,

Alien bird species can help native plants move around, say surprised scientists. (GrrlScientist,

A quest for Bumblebee nests: The missing link. (Amanda Liczner, PhD Candidate, York University, via

Stem girdling roots – Abiotic factors in the landscape and garden.  Watch the video! (Virginia Cooperative Extension, via Youtube)

Beauty is in the nose of the beholder.  “It’s no surprise that a flower releases scent to attract a pollinator, but why would it do it hours before the pollinator is around? New research finds scent can have more than one job.” (Alun Salt, botanyone)

The significance of Cherry blossoms in Japanese art & culture. (Kelly Richman-Abdou,

A lawn is better than fertilizer for growing healthy blueberries. (Blog, Frontiers Science News)

Beware of sleeping queen bumblebees underfoot this spring.  “Scientists at Queen Mary University of London have discovered a never before reported behaviour of queen bumblebees.” (Queens Mary University of London, via

Using arborist wood chips as landscape mulch. (Dr. Linda Chalker–Scott, WSU)

Plant researchers are providing new insights into basic cell division in plants. (Martin-Luther University Hall-Wittenberg via

Understanding the mysteries of plant diseases: Prevention, Control and Cure (Part 3 of 3 in this blog series.) (Jim Downer via

Pretty sly for a whitefily– “One of the world’s worst agricultural pests corrupts the alarm signals of plants, disarming those that otherwise might prepare for an assault.” (Ed Yong,

Life in a cubic foot of a lawn. (Charley Eiseman,

Photo: WSU

Great pruning & training resources for fruit trees. (Treefruit, WSU)

How trees and turnips grow fatter – “Researchers unlock the secrets of radial growth… Botanists have identified key regulatory networks controlling how plants grow ‘outwards,’ which could help us to grow trees to be more efficient carbon sinks and increase vegetable crop yields.” (University of Cambridge via

Something is rapidly killing young apple trees in North American orchards and the Scientists are stumped. (Erik Stokstad,

Watch this great Ted Talk! “Ew to awe: Your view of bugs may never be the same.” (Danae Wolfe via

Cornmeal and corn gluten meal applications in gardens and landscapes. (Dr. Linda Chalker-Scott, WSU)

Check out these amazing illustrations of the nervous system of a honeybee. (Eric Keller,

Plant defenses against them drive diversity in tropical rainforest.  “Researchers have been baffled by tropical rainforest diversity for over a century; 650 different tree species can exist in an area covering two football fields, yet similar species never grow next to each other. It seems like its good to be different than your neighbors, but why?” (U of Utah)

Salal with thrip damage, Photo: Ask an Expert

It’s not Azalea Lacebug damage!  Find out what’s really happening to Salal at the coast. (Ask an Expert, OSU)

Fungi fight plants. These symbiotes are also sometimes screens when it comes to establishing plant ranges.” (Staff,

Compound of berries and leaves of American beautyberry, Callicarpa Americana, show potential as repellents against mosquitoes and, now, some ticks. (Luis Pons,

Antennal sensors allow hawkmoths to make quick moves. “All insects use vision to control their position in the air when they fly, but they also integrate information from other senses. Biologists have now shown how hawkmoths use mechanosensors in their antennae to control fast flight maneuvers.” (Lund University, via

Mosquito Hawk? Skeeter eater? Giant Mosquito? No, No, and No! Learn about Crane Flies. (Leslie Mertz,


PDF Version May 2019

“It was such a pleasure to sink one’s hands into the warm earth, to feel at one’s fingertips the possibilities of the new season.”
Kate Morton









The Merry Month of May!

OSU Master Gardener volunteer opportunities in the metro-area flourish in the month of May as the gardening season begins in earnest!  The Master Gardener helpline offices are abuzz with lots of inquiries from home gardeners.  The Farmer’s Market season is kicking off and there is a flurry of activity and need for eager volunteers at our supporting Chapter’s demonstration gardens!  There are also new learning opportunities with our Master Gardener hands-on workshops and mini-classes.  Learn all the details…

2019 Farmer’s Market Season Begins!

An early start to the Master Gardeners Farmer’s Market season, a chilly morning in April at the Hollywood Farmer’s Market

Master Gardener Clinic Booths are popping up at Farmer’s Markets around the tri-county area. Master Gardeners are answering home gardener’s questions at the following markets in May.

Beaverton – Gresham – Hillsdale – King – Lake Oswego

Milwaukie – Oregon City – Sherwood – Tigard

Sign up for a shift on CERVIS or contact the clinic coordinator, Marcia or Janet for assistance signing up.






Master Gardener Office Helplines

It’s amazing what you can learn educating others and that opportunity is there for all who volunteer at the Master Gardener office helplines!  Research and collaborate with fellow MGs while educating the gardening public.   Sign-up on CERVIS or contact a phone coordinator.

Clackamas County, Janet Hohman,
Multnomah County, Janet Hohman,
Washington County, Jenifer Halter,





Keep an eye out!  Special Volunteer Events.

Special volunteer events arise throughout the season so be sure to watch for email announcements from MG program staff or postings on CERVIS to snag a slot at one of the many special volunteer opportunities.



Speaker’s Guild Mini-Class

Are you interested in becoming a presenter for the Master Gardeners Speakers Guild or are you already a Speaker’s Guild presenter and you want to brush-up your presentation skills?

Our 3 Master Gardener Speaker’s Guild coordinators are presenting 2 mini-classes in May to support those interested in becoming a Speaker’s Guild presenter.

Friday, May 17th @ the Happy Valley Library, Happy Valley, 4pm to 5:45pm

Saturday, May 18th @ the Holgate Library, Portland, 3pm to 5pm

These mini-class will focus on tips and tricks for giving engaging presentations that offer quality garden information, while creating a welcoming, fun experience for your audience.  Learn how you can branch out as a garden educator sharing your passion for gardening and the proven gardening techniques you have acquired through your Master Gardener training.  Meet our 3 Master Gardener Speaker’s Guild coordinators and learn about the resources and support available for you as part of this fun, rewarding volunteer opportunity.

Register for a Speaker’s Guild Mini-Class on CERVIS.  Look for the ‘Speaker’s Guild Mini-Class’, pick your preferred date and register.

Speakers Guild

The metro-area Master Gardener’s Speakers Guild members make presentations on a variety of gardening topics to community groups throughout the metro-area.  Requests for presentations come from garden clubs, civic groups, libraries, schools and other organizations.  For some topics, we have prepared PowerPoint presentations and for other requests new programs are developed.  Through the Guild, you will find opportunities to develop and/or deliver programs in subjects that interest you.  Support is offered to those new to public speaking.  Volunteers can also shadow presenters that are more experienced.  You get to choose presentation opportunities that appeal to you (e.g. date, location, small groups, large groups, with PowerPoint presentation or simply a demo or talk).  The Speakers Guild is a rewarding Master Gardener activity where you can dispense sound gardening information to the gardening public.

*Time spent at these Speaker’s Guild mini-class can be counted as ‘Program’ volunteer hours.  Perennial Master Gardeners can count the class time as EITHER ‘Program’ volunteer service hours or ‘continuing garden education’ hours.



Hands-on Workshop Openings!

A few slots remain for our 2019 training workshops.  Sign-up on CERVIS, plus find details about the workshops, including location.  These workshops are a great way to expand your gardening know-how in an interactive, hands-on environment with expert instructors.

The following workshops still have openings as of the composition of this newsletter.

  • May 10 – Beginning Vegetable Gardening
  • May 31 – Summer Fruit Tree Care
  • June 1 – Summer Fruit Tree Care
  • June 8 – Beginning Vegetable Gardening
  • June 15 – Plant Propagation

Note: If you are interested in a workshop that is full, add your name to the waiting list – as openings often occur.

Another Great Series of Advanced Training Webinars

The 2019 Master Gardener Advanced Training Webinar Series is off to a great start.  Here are the next 2 scheduled webinars:

Coddling moth infested apple. Photo: Michael Bush, WA State University Extension

Project Happy Apples: Reducing Codling Moth Damage in Backyard Orchards
Presented by Amy Jo Detweiler (OSU Extension)
May 21, 10am PT
Details & pre-registration info:

“First Look” Reading a Pesticide Label to Protect Bees
Presented by Matthew Bucy (OSU Undergraduate Honors student)
May 30, 11am PT
Details & pre-registration info:

If you are unable to participate in the webinar live, be sure to check back as recordings are made available a couple weeks following the live event.

2019 Webinar recordings:

2018 Webinar recordings:

Frequently Asked Questions…

How do I log my volunteer hours?
To maintain an ‘active’ Master Gardener status or to complete your Master Gardener training you need to log your volunteer and education hours on a 2019 Volunteer log sheet and submit them to the MG program office by October 1, 2019.

You can download the log sheets at the Metro MG Program Volunteer Portal.  Just click the on the 2019 Volunteer Log Sheets link.  There you can choose between a Word Doc or Excel sheet.

Does CERVIS track my hours?  Yes, CERVIS does track your volunteer hours, BUT you need to transfer those hours onto your Volunteer Log sheet and submit them along with your other volunteer hours.  To access your history log into CERVIS and go to “Report Management”, then click “View or Print Volunteer Activity History” and transfer those hours to your log sheet.

What hours do I log?

  • Interns – log your volunteer hours and the Hands-on workshops that you attended
  • Perennials – log your volunteer hours and the continuing garden education/recertification hours you attended

Then simply submit all volunteer and education hours to the MG program office by October 1, 2019.



The Plant Sale Trifecta Continues!

Megan displaying a plant for sale at Gardenfest 2019

The Washington Co. Master Gardeners had a hugely successful fundraising plant sale on April 27th.  All who attended the inaugural, 2019 Gardenfest found glorious plant offerings, valuable gardening information to ensure a successful garden, and happy gardeners all around!  Hats off to all who made Gardenfest a wonderful success!

The plant sale trifecta continues, so be sure to join in the upcoming Chapter festivities…

Spring Garden Fair, Saturday, May 4th , 9am to 5pm, and Sunday, May  5th, 9am to 4pm
Cruise on over to the iconic Spring Garden Fair to find a treasure trove of perennials, annuals, shrubs, trees, small fruiting plants, veggies, herbs, garden tools, and garden art!  10-minute University garden classes, pH soil testing, kids activities, a raffle, and more!  Clackamas County Event Center, Canby

Incredible Edibles Plant Sale, Saturday, May 11th, 10am to 3pm, a community celebration for home-grown goodness – organic veggie, fruit and herb starts will get you growing!  Plant. Grow. Eat. Workshops, music, kids activities, a raffle and more! 1624 NE Hancock Street, Portland.

Dig-in!  Lend a Hand and Learn at a Demonstration Garden!

Hands-on learning in any of our ‘Partner’ demonstration gardens is rewarding.  Each garden offers unique active, relevant, learning opportunities.  Contact a coordinator and dig in!

Clackamas County has the following great hands-on volunteer opportunities:

  • End of the Oregon Trail Interpretive Center – Check in to see how you can join the fun!  Contact: Sharon Andrews 503-577-7493
  • Hopkins Demonstration Forest – Tend native plantscapes – in a beautiful forest setting! Contact: Frank Wille 503-342-6699,
  • Grow-An-Extra-Row and Learning Garden’ Project at Clackamas Community College – Help to grow food for those experiencing food insecurity. Contact: Nancy Muir 503-789-6970

Multnomah County Master Gardeners have over 1.5 acres of garden where you can learn and grow:

MGs at the Jenkins Estate Garden Give Peas a Chance

Washington County Master Gardeners have two wonderful demonstration garden locations:

  • Learning Garden at Jenkins Estate – Lend a hand in this beautiful landscape. Contact: Marilyn Berti, MG contact: Marilyn Berti
  • Education Garden at PCC Rock Creek – be part of the exciting beginnings of a fabulous community garden partnership! Contact: Sue Ryburn at







Woodland Wildlife Field Workshop

Our Clackamas County Extension Forestry team is presenting a Woodland Wildlife Field Workshop, on Saturday, May 18. Spend an informative day in the beautiful Hopkins Demonstration Forest.  This workshop will be led by two great wildlife biologists: Fran Cafferata-Coe, certified wildlife biologist with extensive consulting experience in applied wildlife biology on working forests; and Jimmy Taylor, research wildlife biologist for the USDA Animal and Plant Health Inspection Service (APHIS) in Corvallis.

Register now and learn more here!