The mealybug Palmicultor lumpurensis, which has been in Florida for several years, has been found in southern California fairly recently (though it may have been there for a while) and has been seen in Texas. We published "New Invasive Species of Mealybugs" by Greg Hodges and Amanda Hodges in the August 2005 issue of BAMBOO (Vol. 26, Issue 4, pp. 16-18.) Here are recent comments by several bambuseros.
[Ed. note: All chemical trade names listed are trademarked. Always read and follow label directions and precautionary statements.]
Palmicultor lumpurensis, a bamboo-specific mealybug, was first discovered in Orange County, Florida (Orlando) by entomologist Dr. Greg Hodges in 2002. This mealybug has an airborne adult stage and is also moved around and farmed by ants. Of course, moving infested plants also moves the bugs.
By Robert Saporito. Loxahatchee, Florida
Regarding the level of damage caused by this mealybug: I've seen many places where the mealybug is present but the owner of the bamboo is unaware. Infestations can range from almost invisible to so heavy that the new shoot tips are covered with webbing. The latter situation usually causes shoots to deform or abort. The heaviest infestations occur in warmer months but the bamboo shoots are growing so fast that they seem to shoot right through the bugs before any significant damage is evident. I saw this in one of the Disney parks. Also, the mealybugs have no interest in mature bamboo tissue, only shoots and branch shoots.
Most of the Bambusas are mealybug favorites (esp. edible shoot producers, species with dense secondary branching or persistent culm leaves), Dendrocalamus is affected to a lesser degree, and Gigantochloa almost never. I think control in individual collections or nurseries is no more difficult than for any other insect pest. Yet there are plenty of bamboos growing in uncontrolled areas and vacant lots that will provide safe homes for these pests. Uninspected plants will be sold by hobbyists and by eBay vendors. I don't expect to ever stop watching for this bamboo mealybug.
The mealybugs are multi-stage insects and are easily identified when they are surrounded by sticky white webbing, almost always on new shoot tips (culm tips or branches). If you see unusual white substance on shoot tips, peel back the culm leaves and you should see small pink bodies in the webbing or on the culm. Sometimes natural white powdery bloom on the new shoot can appear to be the webbing, but it is a false alarm. Make sure you look for the bugs before making an assumption of infestation. Usually the bamboo shoots develop with no adverse effects. Occasionally, the infestation is so severe that the culm aborts. Mealybugs won't kill a clump of bamboo but they can get ugly and possibly cause shoots to abort.
The mealybug destroyer (Cryptolaemus montrouzieri) can be effective, at least short-term. This beneficial ladybeetle loves these mealybugs and will quickly eat any active colonies.
Systemic and contact insecticides are effective. A detergent (Ivory dish soap is great) should be added as a surfactant if you foliar spray with a contact insecticide, as the webbing is difficult to penetrate with a water-based solution. The key is to thoroughly spray your bamboo — all sides, top to bottom. Don't miss any part of the bamboo and spray out to the drip line on the ground. Then re-apply every 10-14 days for at least three cycles. Do this even if you don't see any new mealys that have hatched. You have to break the cycle. If you spray once or twice and think you've eliminated the problem, new bugs will appear in a few weeks to taunt you.
On a commercial scale, or for the bamboo-hobbyist with a large collection, the formula below is thoroughly effective in eliminating and preventing any mealybugs (and most other sucking insects). These products are not yet labeled for use on bamboo plants (although they are labeled for mealybug control on other plants). I'm only providing information on what works for me. I do not assume any product liability. Three different tank mixtures, rotated every 2 months:
The Safari treatment seems most powerful immediately with contact and systemic controls, but it is important to rotate insecticides. I haven't used Orthene (acephate), but reports indicate that it is also an effective control. A .773 lb. can of Orthene makes 150 gallons. Obviously, take measures to prevent getting any of this stuff on your skin or in your lungs.
By Lennart Lundstrom, Hilo, Hawaii
I use Neem oil for insect control, it has the same smothering effect as ultra-fine oil but with the added advantage of acting as a growth regulator (survivors are sterile). Neem oil also acts systemically with increased effect in repeat applications. If you are trying to hit the whole plant, I suggest using a backpack mist blower. If you modify the air-feed tube with the addition of a 45-degree 2" PVC fitting, you can send the mist solution 40 to 50 feet straight up. The blower I use is made by Stihl; other blowers may have different dimensions.
If you are looking for alternatives or something to use in rotation with Safari (a good idea to avoid creating resistant pests), I also recommend Distance, another growth regulator, Imidacloprid (Marathon, Merit etc), and Conserve.
I think that there are many other methods out there for insect control other than the high toxicity route. For instance many homeowner/gardeners in Hawaii use Original Scent Dawn dish soap as insect control; this stuff also gets rid of lichens and mosses.
By Mark W. Caspermeyer, Orlando, Florida
The bamboo mealybug has been a really big problem for me in Central Florida. I had tried all the natural (releasing lacewings, mealybug destroyers and ladybugs) and less toxic means of control (Ultra Fine Oil) for a year or two — with no great control.
At Robert [Saporito]'s suggestion I went to using Safari every 2-3 months (sprays and drench) as well as some Di-Syston. It is somewhat successful, but I can only spray the bottom 20-30 ft of my 50-60 ft tall bamboo. The Safari drench I did on my Gigantochloa atroviolacea clump nearly killed it.
I hate thinking about all that poison going into the environment. It has been labor-intensive and quite expensive (a 3 lb. container of Safari is over $300). I would no longer even consider eating my shoots, as I did regularly before the mealybug problems, when I was growing "organically."
I often think about what a disaster it may become for the shoot farm in California that we visited several years ago. I have given up the notion of growing shoots on a larger scale here since the appearance of the bamboo mealybug. Meanwhile, I am hoping that a large population of mealybug-eating beneficial insects will eventually develop.
As Robert said, the Safari is much kinder to the beneficial bugs than most other poisons.