Bamboo mites

[ShmuBamboo]

I have been to several major bamboo plantations in the PNW over the past several years that have bamboo mite infestations (and several that have not). They make the groves and plants look ugly. I was at one place last weekend in Oregon and my girlfriend wanted to buy some boos, but I refused to let her. The owner said that the boos for sale had been sprayed for mites, but the boos were within winddrop of the other plants that had the mite infestation.

I can set up a quaranteen area here for new boos (over 100 acres on this farm) but that is a pain. Also spraying is a pain. We have enough problems with plant and animal bugs and virus here already. I do not want boo mites, but I fear that the PNW is getting inundated with them. The more I read, the more it seems to indicate that the PNW is a major source of boo mites of late. Which is odd, as Oregon and Washinton seem to be off the states listed with boo mite problems. At a nursery up in Washington that we visited last year they pointed the mites out and they refused to sell us any boo plants because of them.

Anyone out there have experience with buying or digging up potentially mite infected boos and getting rid of them? It seems that Moso is the most suseptible to them (good thing that I am not a big moso fan; I prefer the variegated culm timber types, and mostly Phylostachys). It also seems that I have been lucky not to have them after collecting boos from several places in the past several years.

[Mark Meckes]

We never saw any bamboo mites on our bamboos here in Austin, then several years ago we harvested some poles from an old (nearly 100 year) untouched Moso (Phyllostachys edulis aka P. pubescens) grove in the southcentral US.
We brought back bundles of the beautiful cut off branches for craft use, with leaves intact, and laid them out to dry and lose their leaves ...

... In a previous year someone wanted to get rid of their black bamboo (Phyllostachys nigra), and we dug it up and planted it (near the same vicinity that we laid the branches out the following year).
The nigra had no mites, but two years later we were shocked to find that they were teaming with bamboo mites. (They love P. nigra species).
At this time we couldn't understand where they came from, as we had not acquired any other new bamboos for a number of years.
It wasn't till we returned to the Moso grove in the following year when we saw that the leaves were heavily infested with bamboo mites and deduced how we acquired them.

Now this came as a surprise to me as I had presumed from previous discourse on this subject that the bamboo mite had been introduced via the Northwest US.
I discussed this with someone who had some knowledge on this subject and apparently a bamboo mite species had been observed on bamboos in the southeast in the early part of the 1900's. I do not know if it had been introduced long ago with the early bamboo introductions or if it already existed with the native Arundinaria gigantea.
After subsequently travelling to the SE region, visiting some long standing collections, I did detect the presence of this critter, though not to the extent on some species as I have since seen on the above mentioned species.

I asked if it was the same species as that found in the Northwest, and was told that the one in the Northwest is a different species, with the only difference being that the Northwest species has a bigger 'pecker'.
(I do not have a high powered microscope to verify whether this is the case)
For many years I had faithfully renewed my nursery license so that I could sell B&B bamboo from my backyard, which provided a seasonal supplemental income. I had been wanting to retire as a grower as I had too many other areas of interest that I wished to purse.
Discovering the mites gave me the reason to end this chapter of my life as a grower.

Discussing the spread of this critter with someone, they pondered whether it could be spread by birds - mites hitching a ride, or possibly wind borne.
I do not know, but it has been slow to spread beyond known patches and the bamboo species that it seems especially attracted to on our property.
However it is nigh impossible to think about totally ridding it without taking drastic measures.

Mark

[ddhort]

You have both commented, in a carefully crafted way, that when the subject of the incredibly resourceful spider mite finds its way into your domain you more or less are resigned to keeping population and damage to a minimum.

My intro to this critter began many years ago in interior situations. Neophyte that I was, I imagined conquering this tiny arachnid in one giant step. Although the arachnicides that have been formulated over the years are more effective than ever, they are expensive and a pain to apply.

The decisive moment for me was running across a chart(I have held numerous pesticide applicators licenses) which showed the population growth rate of mites versus temperature. The rate turns logarithmic as temps approach the 70's and 80's. A scary proposition...oh look! Only 3,000,000 mites were born over the weekend.:(

Good air circulation and occasional washing (if you have the water) is the only sane outlook I've found for this pest.

David

[Mark Meckes]

Hi David,
I seek culmsolation through your comments. ;)

What makes this leaf scraping critter particularly pernicious is the way it forms a snug web over it's egg mass, making it difficult for predators to access them, or to spray them off with a blast of a hose, as shown here on the underside of a Phyllostachys nigra leaf. (They can also form their webs on the top of the leaves)

http://www.bamboocraft.net/bamboo/data/527/medium/PnigBmiteAuTX050520-413.jpg (http://www.bamboocraft.net/bamboo/showphoto.php?photo=4290)

(I am only guessing that this is a Schizotetranychus celarius as it may (or may not) be another species of this genus.)

It is fortunate that bamboo replaces some of it's leaves annually as this provides at least one mechanism for preventing culmplete decimation.
Of note, when I lived up north in frigid climates, any insect pests on bamboo were very minimal due to the cold temperatures outright dessicating the foliage, albiet at the expense of having smaller size plants.

An important aspect I've found, both for pest management and a healthier grove, producing stronger culms is selective thinning.
This begins during the shoot emergence period, removing the smaller culms that don't have much of an chance, or struggle for survival throught their life culmpeeting with the bigger dudes, and ends with the rotation of the culms, or harvesting/removal of the culms that have reached optimum maturity.
This provides better air circulation and less culmgestion, and gives more access to sunlight, to grow and nourish new leaves.

Another thing concerning pests and their affect on the overall the health of the bamboo is when there are multiple types of pests affecting different parts of the plant.
We have been very fortunate that during the introduction of the many many bamboo species into this country, that we were not also endowed with the many hundreds of pests that commonly occur in their country of origin.
However the pests that did come along can be possibly even more pesky in nature, because we don't have the natural predators that existed along with them in their country of origin.

Here's one example of a pesky pest which, though considered a minor pest on it's own, when hanging out with the bamboo mite, incurs additional and much more impacting stress to the plant:

Antonina pretiosa - Noxious Bamboo Mealybug
http://www.bamboocraft.net/bamboo/data/536/medium/1MVC-118F.JPG (http://www.bamboocraft.net/bamboo/showphoto.php?photo=876)
Here can be seen the scrape marks caused by the bamboo mite on the leaves, while Antonina pretiosa is busy sucking out the living daylights of new leaf buds valiantly attempting to grow from the branches of this Phyllosatchys nigra.

It's interesting that Antonina pretiosa which favors and was possibly initially introduced and distributed through the tropica/warm temperate clumping bamboos like the Bambusa multiplex species, will also cross over to various genera of the temperate running varieties, (and is especially fond of Phyllostachys nigra species), whereas the Bamboo Mite, as far as I have been able to ascertain, is uninterested in Bambusa species.

Mark

[ShmuBamboo]

Amusing about your reasons for retirement from boo selling from the backyard. I believe that the boo mite has been the demise of several large plantation boo-lovers here in the west. I believe that there are at least 2 and possibly as many as 6 different mites that attack boos. The science is lagging behind the exponential curve of these bugs. They seem to be boo species preferable; meaning that some mites are worse on some types of boos more than others. Moso seems to be the hardest hit by mites as a result of their leaf structure. I have no boo mites here... yet. But we are in a very isolated place surrounded by hundreds of miles of nothing but doug fir forests.

I have been propagating and selling plants as a back-yard horticulturist/nurseryman for many years. As soon as I get into a new plant there is a new bug or disease to consider. In growing orchids, the real scurge is Cymbidium mosaic virus. Scale also love them, and cymbidiums are also suseptible to the two-spotted spider mite (really plays havoc in warm weather). I resorted to using Cygone-e to keep the mites under control when I was entering my orchids for displays and at shows. Roses are similar, and the disease are too many to list. Mites can defoliate a rose bush in a single week of hot weather. I was always spraying them.

I also have been growing several types of lesser known crosses of cane berries for the past 30 years. Last year we were hit with a new type of blackberry rust that came in from New Zeland. The wild vines have it, and the bees and birds transfered it to my berry vineyard. Anyway, my berry canes that have for 30 years had been disease-free are riddled with rust now. Last year I had a very low crop yield. I was thinking of expanding production here to several acres and selling live plants, but forget that now. I have been trying varius ways to lower the impact of the rust, but so far the rust is winning. The nematodes are gaining in my garlic plantings as well (I grow over 35 types of garlic here). Nematodes are nearly impossible to erradicate from the soils, save for ethyl bromide applications (nasty stuff that I refuse to use; it is being phased out for commercial use).

Then there are grapes... well, I went ahead and planted a test vineyard here this spring anyway, with self-rooted pinot noir dijon clones. Grapes are suseptible to a variety of bugs and diseases here, including Pierson's and Phylloxera. I took a risk planting self-rooted vines here (far lower cost) that are suseptible to phylloxera. The idea being that we are isolated, and there is a remote chance of introduction of the bugs here. Then of course there is the scurge of the west lately, SOD (sudden oak death). A fungus that attacks and kills a great many types of trees and shrubs. I imported quite a few redwoods from California here just before the SOD restrictions went into effect a few years ago. Then I saw several of our rhodies wilt and die the followin spring. I was tramatized by the possibility of them having SOD and infecting the 100+ acres of trees here... , so I called the ODF. They came out and tested my rhodies and redwoods. They all came back disease-free... phew!

Anyway... back to boos. Yes, there are several types of boo mites. Or rather, several types of mites that attack boos. Boo mites have been observed and been around in the US for maybe 100 years or so. But lately there seem to be more infestations, and probably new types of mites. More and more plantations and collections that I have seen here in the west are infected or have been infected in the past 5 years or so. These later types of mite infestations seem to be more devastating to the visual appeal of bamboos. It is noticable as soon as I go into a grove. Mite leaf damage.

Seemingly sprays like Avid work on boo mites, if you can get it onto all the areas of the plant leaves and into the webbing. The Oregon horticulture posts I have read on boo mites recommend soap and water sprays as well as miticides. Other posts I have read by the ABS say using soap, water and oil spray is pretty effective. Costs less, non-toxic, and if you hit them in 2 week cycles you can keep the populations down. We have an endless supply of spring water here though. If you have water restrictions, this may not be an option. As for spreading mites, they will hitch rides on clothing, and they will spread by being windblown. I am glad that you mentioned poles being the source of mite infections; I was considering buying a collection of poles on the cheap from a nursery that has boo mites. No longer. *sigh*

BTW: your photos of leaves do not look so bad. The leaves of the boos infested with mites here have long obvious streaks in them where the mites have been gorging themselves. The leaves are all discolored and look so from a distance. I would imagine that in Texas mites would grow 3x as fast as here in the PNW. The heat in San Diego really accelerated mite populations.