Welcome to Autumn!  I say that with a bit of surprise in my voice.  After all, wasn’t spring just beginning a couple of weeks ago?  Even with the pandemic slowing things down around Seattle, the seasons seem to be changing too rapidly for my liking.   

And yet, Autumn does have a special place in my New England heart.  To be back among the rolling hills of Woodstock for the fresh-squeezed apple cider, the 200 lb. wheels of aged Vermont cheddar cheese, the scent of burning leaves on the breeze and, of course, the insistent knocking on the front door on All-Saints Day or the national celebration that children love and dentists bemoan – HALLOWEEN!   

While I do enjoy the diminutive ghosts, goblins and witches who parade up the front walk, they are no match for those other, more scurrilous beasties who are, even now, reaching out toward the perimeters of our northwestern territory. They come hidden in ship cargo holds, skulking in loads of firewood and flitting on the breezes of our city.

As The Garden Guy, of course I’m talking about insects!  In this case, it’s about new invasive species that mean to do us harm in order to create spaces for themselves.  Most have come in directly from Asia or, indirectly, through Canada and from the east coast.  

These new little beasties will not settle for Halloween candy, not even melt-in-your mouth chocolate.  They are after the trees and shrubs in your yards, neighborhoods and forests.  Here is my subjective list of the top culprits to watch out for and to report to state agencies. We’ll get to that later… 

Murder Hornet:

The first of our Halloween-esque denizens is the much-publicized Murder Hornet (cue the music from ‘Jaws’).  More appropriately known as the Giant Asian Hornet (Vespa mandarinia), it ranks as the world’s largest hornet and can grow to two inches long, with a wingspan of some three inches. 

These hornets need meat to feed their young and they are pretty direct at getting it. Among available protein sources, they prefer honeybees. A handful of Murder Hornets can decimate a honeybee hive in a day. They do so by biting off the heads of our much smaller native and European honeybees and then feeding the headless thoraxes to their larvae. 

Unlike honeybees, Murder Hornets can sting multiple times and have venom several times more potent than any local bee or wasp (think about a hot tack puncturing your skin).   

Fortunately, they are not terribly aggressive around humans unless their nest seems threatened.  Then, they can be people killers. Thus far, they have only been sited north of us in Bellingham, Blaine and British Columbia.  Their potential damage to orchards, flowering plants and the honey industry will be huge should these thugs secure a foothold in our state. 

Japanese Beetle:

The Japanese Beetle (Popillia japonica) is a garden pest native to northern Japan. The glistening green and copper colors of their wing cases give them a look of bronze scarabs which would, fittingly, accessorize a child’s King Tut costume.  

The insect is pretty, especially in the evening sunlight, but the half-inch-long adults eat the leaves of plants, while the larvae attack the roots (particularly the roots of grasses).  Roses are a particular delicacy for them.  

These insects were, and still are, the scourge of my Connecticut garden. Plants already stressed by our hotter summers may not survive with the added pressure of infestations from these invaders. They have been a problem on the east coast and in the mid-west for decades. 

We haven’t seen them in Washington before, but with our new warmer temperatures, they were found in Idaho and at a few sites south of Portland this past year. So, it’s only a matter of time, I fear.

Brown Marmorated Stink Bug:

The Brown Marmorated Stink Bug (Halyomorpha halys) is native to East Asia and was first noticed in the United States in the late 1990s, possibly having arrived in yet another shipping container. 

These half-inch-long suckers will attack a large variety of plants, including many fruits and vegetables. They leave small necrotic patches on any plant eaten, rendering produce inedible for human consumption.  

As a homeowner, you will likely notice an invasion before anyone else because this stink bug initially attacks vegetable gardens and landscape plants. The damage they do to crops and landscapes, as well as the efforts to control them, are costly.  

These beasties will then spend the winter in homes and other structures. Look for them on the south side of your homes as the weather cools. 

Spotted Lanternfly:

Probably the most colorful (and newest arrival) of our Halloween beasties is the Spotted Lanternfly (Lycorma delicatula).  Its red, white and black colors do remind me of a masked kabuki dancer (or a member of the Sith for you Star Wars fans).  Another of the vampire-like piercing-sucking drinkers, the Lanternfly hails from eastern Asia, has spread through the mid-east coast states and is appearing in California and southern Oregon.  

As with the Japanese Beetles, I think it is only a matter of time for the greater Seattle area to see their presence.  Lanternflies feed on a wide variety of plants, with apples, cherries, grapes and plums being among their smorgasbord preferences.  So, another problem for both homeowners and agricultural farms.  

Also, like birch borers and aphids, Lanternflies excrete large amounts of honeydew, which can cover lower-growing plants and promote the growth of sooty mold.  And, I don’t even want to mention what they can do to the outside of a car parked under a ravaged tree.  

These kabuki-looking bugs are about one-inch long and brightly colored (although the youngsters are black at first with white spots).  As members of the leaf hopper family, their flights are very short, more of a hop and glide.  They will be noticeable to you.

With these four harbingers of death and decay prowling the borders of our own Shires, we can all do something to help protect our yards, city and the state economy.  First of all, kill or trap these ‘Most Wanted’ interlopers when you see them.  Then, report any sighting to the Washington State Department of Agriculture, (360) 902-1800 or the Washington Invasive Species Council reporting app, https://invasivespecies.wa.gov/.  

As the citizens in these up-coming battles, we, as simple gardeners, will have a more positive impact on ecology than the folks in the other Washington. Good luck! 

Have questions about this article? Care to suggest a topic for a future gardening column?  Contact your WSU/King County Master Gardener at thegardenguy4u@gmail.com.  Happy Halloween! Beware of both the two-footed and eight-footed creatures that may be wandering your neighborhood streets this month.

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