Pests

HOW TO TALK TO YOUR CHILD ABOUT VERTICILIUM WILT

April 28, 2016: When I was growing up, my father and I never had a serious conversation about verticilium wilt. We had other conversations, which I'm sure he felt were more important, but we never talked about that. I do not blame him for I never had the same conversation with my child. I guess as parents we rationalize by thinking it's not that important or its too delicate a topic, and let the moment, which may never return again, pass by. They will figure it out on their own we think. And some day they will, but wouldn't it have been nice if we could have prepared them for it.

If I had that moment back again, here's the conversation I would have:

FATHER : Sit down a minute, kid. I want to have a talk and I think you're old enough now that you'll understand. Is that OK?

KID: (Nods)

FATHER: You're growing up so fast! Soon you'll be leaving home to start a life of your own. You may have a garden, some property or perhaps just a nearby park, but it is my hope that you will find and fall in love with trees. Love is what makes us human. It gives us the potential to really see ourselves and the potential of others. Where there is the warmth, light and life of love, there is also the darker opposite lurking -cold, dark, death - the two sides of a coin. It is a fact that we must acknowledge but not necessarily dampen that which makes us human. If you happen to fall in love with one of more than 350 species of trees, shrubs, annuals, perennials or vegetable crops, then that dark side may well come in the form of verticilium wilt, a disease that can cripple and often kill a plant.

I know this is disturbing to hear , but it's really important to both of us that you understand. I'd like to tell you how this might happen and what are the signs that it may be coming. Is that OK?

KID: (Nods)

FATHER: Verticilium wilt is a fungus disease that lives in the soil. It can live unseen and undetected by mortal eye for up to 14 years in the soil. It invades a plant through the roots and will travel to the xylem, the water conductive tissue of the plant. There it will grow and flourish and block water conduction to the leaves. It causes the leaves to wilt and die, which leads to branch dieback and eventually crown death. As leaves die, the roots that supply them die for lack of food. In trees, this process can go on for several years before tree death can occur.

There are a number of other diseases and environmental disorders that can cause branch dieback. One of the ways to identify that V. wilt is taking place is to slice a newly wilted twig diagonally. You will see olive-brown, brown or black streaks in the sapwood (the last few rings of growth).

(Father sighs. Wipes some moisture from his eye and looks away out the window)

I once had a big leaf maple I was very fond of. It was old and venerable and shaded the yard. We had a summer that was very, very dry followed by a very, very wet winter and the next spring I found some dead Sapwood streaksSapwood streaksbranches in my beloved. The next summer over half the branches died and that winter it blew over taking out a chunk of the garage There was little in my power I could do, except repair the garage.

Once a tree has verticilium, there are no effective treatments for it. One can prolong or temporarily reduce the effect by watering the tree during droughts but there is no un-inevitabling the inevitable. Does that make sense?

KID: (Nods)

FATHER: Here in the Pacific Northwest it is our maples, elms, ashes and cherries that are some of the most susceptible. In my opinion verticilium is everywhere in the soil. It can't be avoided. Healthy, relatively stress free trees seldom show signs of it so reducing drought stress or overly soggy soils can help where practical. If replacing a verticilium killed tree, do not put another susceptible species back. You're just asking for heart ache then.

I guess what I'm saying is that the things we love will eventually die. Let not the hurt of that keep you from loving.

Hey! HEY! Will you please take your Ipod earbuds out! I don't understand how you can hear a word I'm saying!

KID: Whatever.

FATHER: Well, I'm glad we had this little talk. Love you, now.

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THE RETURN OF MOTHRA

Feb 14, 2016: Recently, an observant reader pointed out that in my limited list of insect supervillains I had forgotten one, Mothra! How could I have forgotten the immortal early 60's Japanese monster film in which a giant moth, accompanied by her (Mothra was also a mother) two fairy handlers called the Twins, battles Godzilla. Silks webs versus atomic breath, you don't see that kind of imagination in today's monster movies, by cracky.

Thank you observant reader and how prescient . . . for Mothra has returned!! . . . to the Pacific Northwest, albeit in a more diminutive form. The Asian gypsy moth, whose larvae can dine on the leaves of over 600 species of leaves and shrubs, was found in the Portland Metro area last year in monitoring traps set up. Though it has not made any significant incursions into the US yet , it's potential to wreak havoc is great. Even a small outbreak might cause quarantines of Oregonian timber and nursery stock which would be a big economic owie.

Only seven were trapped but those are just indicators. A single gypsy moth female lays an egg mass that AGM egg massAGM egg masscan contain between several hundred to a thousand eggs. Do the math and it doesn't take long for the population to build. The Oregon Dept.of Agriculture is proposing spraying parts of Forest Park and North Portland this spring with a biological pesticide called Btk, short for Bacillus thuringiensis kurstaki. Its a bacteria that attacks the gut of the gypsy moth larvae (It's the larvae that does the defoliation damage) causing them to stop feeding and die. Btk is selective and only kills a narrow range of moth species larvae.

Spraying anything, particularly aerial spraying as this will be, will surely cause a tsunami of environmental concerns, little of which, in my humble opinion, will be warranted. One can access information on Btk from Oregon State Health Authority at:
https://public.health.oregon.gov/HealthyEnvironments/HealthyNeighborhood...

I feel like Marlon Brando in "Apocalypse Now". You remember the scene where you just see the silhouette AGM larvaeAGM larvaeof his rather large body in the dark of his jungle hut and he's whispering "the horror, the horror, the horror"? I have experienced "the horror" of the Asian gypsy moth's (AGM) close cousin, the European gypsy moth (GM) , which has been ravaging the forests of the Northeast and upper Mid-West since it was first introduced to North America in 1869. As a kid growing up in upstate New York I remember hearing the pitter patter of raindrops on our roof one summer evening, except they weren't raindrops, they were frass (poop) of thousands of gypsy moths in the tree canopies overhead. The next morning the green leafy forest that was our backyard was a skeletal forest. Just the midrib and veins of the leaves were left behind. Oh, the Horror.

Blimp control for GMBlimp control for GMGM outbreaks are cyclical. Every 6-7 years the Horror returns and then it disappears. It actually doesn't disappear, the population crashes due to diseases. Before Bt was around to spray, one of the earlier biological controls were NPV, a type of virus that occurred naturally within GM. Before that, there was the non-biological control DDT, and we all know about that story. Tens of millions of dollars in control efforts later and we still have GM.

The common name of " gypsy moth" is at first odd when you consider that the female adults can't fly and the male adults can only fly a couple hundred yards. However the female has the habit of laying it's eggs EVERYWHERE. That means lawn furniture, car tires, the sides of campers, etc and then these get transported by unsuspecting humans to another location where they hatch. The Asian gypsy moth, though , is a super traveler. Not only does the female lay eggs similarly to GM but both male and female can fly . . . up to 30 miles.

Observant readers that you are, you're probably also wondering how we know the exact introduction date of the GM into North America. We not only know when, but we know who. Some schmuck, by the name of TrouvelotTrouvelotEtienne Trouvelot, brought the eggs from Europe and began experimenting with rearing them as a substitute of Asian silkworm. He thought if he could cross GM with the Asian silkworm he could create a hardy, cost effect silk producer. The problem was the two species are too dissimilar to cross. There not even in the same insect family. What a putz! Instead, some of the gypsy moths escaped and the story continues. To be fair, Trouvelot realized the problem and notified local authorities but nothing was done. He then decide it might be best to hightail it back to France.

Now here's a guy that as a result of a biological blunder created a legacy and a name that is remembered (by me and now by you, at least) for a century and a half. In my golden years, I think about what kind of legacy I will leave behind. How will I transform my name from insignificance to immortality? I could always grab a gun and occupy some federal building but I suspect that's fleeting. Trouvelot's name will go on long after the militia morons' are forgotten. Ah, but be an entomological or botanical terroist? Introduce something that will be a pain in our ecological #@!%'s for decades, now that is lasting infamy.

Kudzu, the vine that ate the South, I'm thinking. Nah, thats been tried before. African bees, yes! Nah, they don't survive our winters. Africanized Russian bees? - Nah, they haven't been bred yet. So while I'm thinking of something really bad I can introduce and achieve immortality and if you'd rather be part of the solution than introducing a problem, there are informational meetings being held the evening of February 17 and morning of February 20 in North Portland. You can find specific info at: tinyurl.com/ODAgypsymoth.

Well, I've got to head back to my barn, where I'm raising something really big and bad, that I can't tell you about.
If found, call me immediately!If found, call me immediately!

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BARK BEETLE BOY: ACT III - THE DRAMATIC CONCLUSION

Feb. 4 2016: So how does an insect that has co-evolved with its host for millenniums suddenly become the Scourge of the West? Climate change, that's what most that study the beetle believe. . . .Ah, there's that climate change stuff again, you're probably saying. The answer to everything these days is climate change, including why my last check at the supermarket bounced and if you're one of the maligned few that are climate change deniers, or climate skeptics, as they prefer to be called, it's got to be so frustrating you just want to grab your rifle and your tinfoil hat and go squat on some federal land. But I digress.

If our winters are getting warmer and our summers are getting drier, as forecast in a 2012 US Forest Service study of the Pacific Northwest, then what happens is a higher percentage of bark beetles survive through the winter. The more that make it through the spring the larger the populations become. The climate no longer acts like a check to the population. Drier summers results in greater drought stress in trees and we know now that's a veritable cavitation symphony (see Bark Beetle Boy-Act II for cavitation explanation) to the beetles.

Our own forest management practices have contributed to the beetle explosion. Diligent fire fighting has reduced forest fires in the past. That's good for timber production and public safety and also the beetles. The ecology of fire is to thin out and cull the sick and unthrifty (overmature trees, suppressed trees, stressed trees).the same trees that are ideal beetle targets. The irony is that as the bark beetle problem gets worse, due in part to fire reduction efforts, the trees that the beetle kills (estimated at 100,00 per day) leads to a dramatically increased fuel load in the forest. When forest fires come now, they are doozies.

So how is the beetle fought in the vast arena that are our Western forests? There are a number of strategies proposed and underway. One is to do nothing. Some scientists believe that natural selection will prevail. That within a tree species population there are individuals that genetically are better adapted to warmer climates and drought stress or can better defend themselves through greater pitch production than their peers. Those "supertrees" survive and pass on their genotypes eventually creating a forest that is resistant. Natural selection is not exclusive though and the beetles can also be co-evolving along with the supertree. Proponents of the watch and wait approach point out that, despite over 300 million spent so far in beetle control measures, overall forest damage has only been reduced marginally.

One of the more active controls is the pursuit of controlled harvesting through logging and pre-commercial of forest stands. By decreasing a forest stand's density, you also increase it's vigor, so a less compact hardier forest is less susceptible to beetle attack. By harvesting dead and dying beetle-killed trees, you are removing the beetle at its buffet. At least that's the logic.

Verbenone packetVerbenone packetRemember pheromones from the last article? They are being used now. One pheromone in particular, verbenone, is being used for controlling mountain pine beetle (MPB)and Ips beetle. The synthetic pheromone is a repellant. It mimics the beetle's "Stay away from my trough!!" scent . It is applied via bags stapled to trees or plastic flakes that are broadcast from the air. Because of cost (~$170/acre), its unfeasible for the forestland, except for very high value small stands. The city of Big Sky, Montana and a ski resort near Aspen, for example, have used this control. Timing is critical with pheromones. It must be out just before the first male beetles fly in the spring. Miss that variable window and you're hosed.

Chemical insecticides are largely ineffective. On high value landscape pines, some insecticides can be used as a preventive during beetle flight but must be applied annually. Once the beetle gets inside the tree no insecticide will work effectively. On a forest wide basis, chemical control is impractical, costly and environmentally unsound. For the homeowner it may be an option but requires hiring a commercial applicator with high pressure spray rig to completely cover the tree. It's not a DIY thing.

Since beetle attacks and drought stress go hand in hand, for the homeowner with a few landscape pines summer irrigation can help relieve that water stress. It's not an absolute safeguard but it helps.

Ending Scene - Bark Beetle Boy
(War torn, smoldering forest rubble. Final battle over. Dead bark beetles by the thousands, crashed planes, burnt out tanks, etc litter the scene. Our hero/ine stumbles through, aghast at the death and destruction. Stops in front of the huge dead prostrate body of Bark Beetle Boy. Behind him/her follows Old Bearded Guy with Suspenders)

Hero/ine: My God! What a cost, but it finally over. Our forests can finally heal now. Our children can finally go alone into them without fear. He (points to BBB) and all his kind are gone!

Old Bearded Guy: Nah, chief. They've gone away, but they're not gone.

Hero/ine: You mean they'll be back?

Old Bearded Guy: Sure, they always have. Maybe not tomorrow or next year but they will be back, and they'll be stronger and smarter and smellier.

Hero/ine: It'll never end?!

Old Bearded Guy: It'll never end.

(Both look into the horizon. Camera pans to dead Bark Beetle Boy. Zooms in to compound eye. One of the three hundred simple eyes appears to wink. )

(Screen goes black. The End)

I have to say I've been a little bit disappointed in the major comic publishers in jumping on this. All I've received from them so far are some cease-and-desist letters about using their names in this blog.
I have, however, received a $50 cash offer for exclusive movie rights from Roy's Comic Books in Minot, N. Dakota. Roy promises to have it in production and ready for a screen debut at the Parker Senior Center in Minot by early 2018. It's not as much as I hoped for, but this story has to get out. I hope you'll join me for its debut.

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BARK BEETLE BOY: ACT II-B

BARK BEETLE BOY!!!: ACT II-B

In the insect world, communication within a species can be through several media. They can communicate through sight and movement, such as the honeybee "waggle dance". They can communicate through sound like the chirping of cicadas. By far the biggest is the media of smell. Pheromones are chemicals produced by insects and animals and even some plants that affect behavior. Sometimes the behavior of another member of your species, sometimes a member of a totally different species (Truffles, for example, produce a pheromone similar to a sexual attractant pheromone produced by mammalian males. That's why pigs can "smell" them and find them) Some have an odor to them, some do not.

The bark beetle's pheromone lexicon is pretty ingenious. When an adult male locates a susceptible tree (remember from Act II-A how they can hear stress), they land on the bark and chew into the inner bark. If they're successful and haven't been drowned by the tree's pitch, they emit a pheromone that attracts other bark beetles, male and female. "Hey. I found a way into the store! There's lots of loot!"

At some point, after a number of other beetles have taken the invitation (particularly the females), now the original colonizers start issuing a pheromone that says, "Buzz off. No room at the trough!" Kind of the chemical equivalent of gang tagging their territory.

Mountain pine beetle galleryMountain pine beetle galleryThe beetles do damage in two ways. First, the adults that make it past the outer bark, begin to feed on the inner bark. The inner bark contains the phloem, the food carrying part of the tree. The female also lays eggs here and when they hatch, the larvae also begins to chew tunnels through the phloem. Its effect is to girdle or sever the highway between the food producing needles and the food needy roots. Roots that can't get food will die and now they can't pump up water and minerals to the needles above. Not good at all for the tree, but the tree still have a shot at surviving.

The second type of damage, the double whammy for the tree, is the fungus that the beetles carry on their body. This fungus, called blue stain fungus, infects the sapwood of the tree. The sapwood is the newest wood of a tree, from the last 3 to 10 annual rings of growth. The sapwood contains the xylem, the water and mineral conducting vessels. The fungus grows rapidly and clogs this xylem up. That means sudden death to the tree. No water, no leaves or needles.

Blue stain fungus got its name because it stains the wood blue. When beetle killed trees go to a sawmill Blue stain fungusBlue stain funguswhat gets milled out are boards with a bluish cast to them. When I was an extension agent in Colorado, a couple decades ago, blue stained lumber was just coming down from a peak demand craze. For awhile, everybody wanted to line their rec rooms with blue stain board paneling. With lots of beetle killed trees and lots of demand, local loggers were doing well. No fads last forever, and soon blue stain lumber was old hat. Instead of beetle killed stands being harvested, they were left standing and the incidences and severity of forest fires went up.

We have now large areas of dead standing timber thanks to the bark beetles. Every year we seem to have a fire season worse than the preceding year. What is causing this escalating plague of bark beetles? How can we stem the tide? That will be Bark Beetle Boy: Act III - The Dramatic Conclusion.

(Note to Marvel: So of course, we'll have the Army, Air Force, Seals and Marines all battling Bark Beetle Boy and the Legion, but to no avail.

Scene: (Field Commander in tent. Military personnel racing around.)
Commander: "Nothing we do seems to work! Every stratagem, every maneuver we make they anticipate! It's as if they read our minds."

(From the dark background of the tent, an old bearded guy in suspenders shuffles up.)

Old Bearded Guy: "Nah, chief, they're not reading your mind, they're smelling it. If you want a chance, you gotta fight smell with smell. Here." (Hands an aerosol can to the Commander)

Commander: "What's this? Date-Mate??"

Old Bearded Guy: " It's a sexual attractant pheromone. Spray this on every tank, plane and soldier we have. Not only will they know we're coming, but they'll come to us. Love will conquer all."

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BARK BEETLE BOY!!!: ACT II

Jan. 21, 2016: In Act I, I introduced our antagonist, the bark beetle and the dramatic question -how will our forests be saved from this rapacious beast? In any good suspense story, I would now portray that villain in a most maleficent light so you would hate it and thereby root for the protagonists (the trees). When you look at how bark beetles interact with their prey, it's pretty tough to paint a black and white picture. For something the size of a mouse dropping , they are remarkably "clever" (if I may use that anthropomorphic term).

Our three biggest bark beetle pests, (the Ips, mountain pine and western pine beetles), are all native to North America. This is no alien invader introduction. They have co-evolved with western pines for millenniums. Why now are they such a plague? That is the dramatic question that will be answered in Act III.

Pitch tubesPitch tubesMany years ago I had a student, in my horticulture program in South Carolina (where they have southern pine beetles), that managed the grounds of a shopping complex. He asked me to come out and look at a group of Loblolly pines that looked like they were dying. They were located in a parking lot island surrounded by other healthy pines. Four trees out of that group of twenty or thirty were showing decline (browning and dropping needles) and little white irregular bumps, or pitch tubes, on the trunk. These trees were under attack by the southern pine beetle but why only four trees and not all the trees surrounding them? When I started questioning the groundskeeper, he told me that one of the trees had been struck by lightning in a storm two weeks before. Lightning often does more damage underground to roots than is exhibited aboveground and more than likely the four trees all had root damage due to the lightning grounding out. That explains why beetles attacked these trees but did not explain how they can detect stressed trees. When I'm stressed, I swear a lot and snap at people, but I've never seen that with trees.

The reason why bark beetles attack stressed trees is that stressed trees are less able to defend themselves. When a bark beetle attacks a pine, the adult must first chew through the outer bark into the nutritious inner bark, which contains the phloem, the food bearing "arteries" of the tree. The trees defense is to produce large quantities of pine pitch in an effort to drown the invading beetles. Those are the pitch tubes you see on an attacked tree. Healthy trees are very effective in this defense and any bark beetles that attacked healthy trees would not fare well in this world. So in the constant evolutionary cat and mouse game, the beetles have developed a way to sense stress in trees and thereby improve their success. That was something that was widely known, even by me, back in the stone . . . well awhile ago.

But how do they do that? How? How? That question bothered me for years. Alot! Not such that I lost a marriage or jobs or took to excessive drinking over it (though I think that would be a great idea for the protagonist in the movie), but I thought about it frequently. One day I was at a seminar, and an entomologist was talking about bark beetles and he revealed the secret . . . they hear it! Talk about a hosanna moment! And (this is even more amazing!) what they hear is cavitation within the tree! "Really?"you're saying"Cavitation? That's amazing! What the h. .. is cavitation?"

I'm glad you asked. There is cavitation in pumps and there's cavitation in the xylem (water conducting tubes) of the tree. Both types of cavitation, the pump kind and the tree kind, involve air bubbles getting into the stream of fluids. In a mechanical pump, it causes a rattling. In a tree, it cause causes a rattling, though not at a decibel that you or I or any animal can hear, but the bark beetles do. Trees that are healthy don't have air bubbles in their sap, trees that are drought stressed or having dying roots, say from lightning strikes, do. There is even a branch of science research called acoustic ecology.

For me, the answer to that long vexing question filled that void in my soul that nothing else before could, even the excessive drinking . . .well, forget that last part. (Note to Marvel: Final Climactic Battle Scene: Large army flatbeds pull up with huge megaphones mounted on them and atop them are mounted megaton bug zappers. Our sober protagonist hero/ine stands in front as the beetle horde approaches. Pretty dramatic, eh.)

Once the bark beetle detects the stressed tree what happens next is even more, or, at the very least, AS amazing. And this time, its involves the sense of smell. And that, most patient reader, I will reveal when next I blog : Pine Beetle Boy!!! Act II-B. Until then, don't excessively drink and go into the forest alone.

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