unknown bamboo pest (Ans. Noxious Bamboo Mealybug)

[michael]

Hi everyone, I'm new to bamboo and have a sick plant. It is bambusa dolichomerithalla 'greenstripe'. It has lots of ants on the plant, and the joints appear to be discolored and sick looking (see the attached picture). I have applied an insecticidal soap about 3 times within 2 weeks, with no results. The leaves look wilted and some have dried yellow areas. Any tips greatly appreciated! thanks in advance, M

[Mark Meckes]

Hi Michael.
If you see a white substance in branch sheaths or at branch leaf buds of culms that are fully developed then it is quite probably:

Antonina pretiosa (http://www.bamboocraft.net/bamboo/showgallery.php?cat=536) - Noxious Bamboo Mealybug (pics at the Gallery Bamboo Flora)

Sometimes, but not always, white thread-like filaments can be seen protruding from the white substance.

Another clue is a black coating on leaves called sooty mold, and this is caused from the "honeydew" that the mealy bug exudes which is also harvested by the ants.

This is a quite common pest on species of Bambusa, Phyllostachys and some other bamboo Genera.

It's difficult to eradicate with contact insecticides (without multiple applications) because the critters can find protection under the branch leaf sheaths.

As they are sucking insects, another treatment used are systemics, which are are applied in liquid or granular form and drawn up by the plant into these locations.
One all purpose product on the market is Bayer Tree and Shrub.
Also check other products used in treatments for mealybugs on other shrubs.

I am unfamiliar with these applications and hopefully others can share their experiences dosages and frequency of application.

Usually the damage cuased by this critter is more cosmetic - less life threatening.

The yellowing of leaves could also be due to other factors.

See also this discussion: Bamboo leaves are yellowish (http://www.bamboocraft.net/forums/showthread.php?t=2642)

Mark

[ddhort]

Hello All,

As Captain of the USS Bambusa Mark has again steered us in the right direction.

A few hints: make sure your grove can breathe. Air circulation is an important environmental factor in insects establishing a stronghold. Just cull some of the oldest canes.

Hose the remaining canes with a sweeper nozzle attached to your hose. Go from bottom to top, concentrating on the nodes.

Use any method you're comfortable with in ridding the grove of the ants. The mealy is providing them with a food source so the ants will do anything to protect that source. The ants will attack any mealy predator and I've witnessed ants actually 'herding' mealybugs by bringing them from the nest into the plant during the day as if they were cattle ranchers! Never underestimate the evolutionary power of nature.

If you're still plagued by the mealy then systemics should be considered, although it can be expensive if the grove is large. Bayer does have a systemic, look for the active ingredient imidacloprid.

David

[michael]

Hi Mark, just wanted to say thanks for the mealy bug suggestion. I purchased a systemic (Bayer Tree & Shrub) and applied it 7 days ago...the ants have disappeared, the plant looks much better, and I'm hoping the mealy bugs are gone. Was a bit puzzled on the dosage size, opted for using the recommended size for a 1' tall bush, the bamboo is about 2' tall. Anyway, thanks again. M