Wednesday 17 August 2016

Mysterious White Insects on Madagascar Dragon Tree: Mealybug Infestation or Scale Insect Outbreak?

We further interrupt this already un-routine blog for another digression into a mysterious plant insect investigation. But, this story actually begins with a consideration of air quality in space station and how I acquired these specific houseplants in the first place. If you're interested in the problem of volatile solvents in household air sprays, and the afflictions suffered by tropical houseplants, read on...

We live in a top floor flat which has its windows on its roof. Air doesn't really "blow" through the house so much as it kinda randomly pours in, and this flat definitely has got some humidity and ventilation issues. I used to combat this with air sprays, but then I became curious about how air sprays work, and ended up finding out that a lot of air perfumes including my sprays of dubious provenance (thanks TK Maxx) actually may contradictorily deprove air quality in enclosed household spaces. Furthermore, many household cleaners and pre-made wipes were likely to release more volatile organic compounds into the trapped air.

So I got George to carry home three pots of Dracaena Marginatas (Red edged Dracaena), which were one of the plants studied in the NASA clean air study. The study was trying to determine which household plants would be potentially effective in cleaning the air in space stations, but obviously it also has very useful applications in indoor earth habitats.

This particular type of Dragon Tree was found to reduce the levels of benzene, formaldehyde, trichloroethylene, xylene and toluene in the air by just living in the room. They are very low maintenance and rather importantly, they were also on SALE at the Homebase closest to us...

I also tried to switch to more basic methods of doing the household cleaning and descaling with combinations of citric acid, sodium carbonate, and Dr Bronner's castile soap. Say what you will about the crazy text all over the Dr Bronner soap bottles (bringing new meaning to soapbox - its certainly Dr Bronner's soapbox for his unusual moral philosophy), but the soaps work excellently and definitely do the job of keeping 'Spaceship Earth' clean.



Dr Bronner
Gaze upon this amazing picture of Dr Bronner from the 2015 ALL ONE REPORT, which begins with these words:
"In all we do, let us be generous, fair & loving to Spaceship Earth and all its inhabitants."

This morning whilst cleaning the bathroom in anticipation of first ever visit of my parents to London (and visit to our flat here) - I discovered that the Madagascar Dragon Tree living in the bathroom was covered in tiny white ovals! It was so horrifying I didn't take a picture of it. It wasn't mould, I could see that this was a bug problem, but these tiny stationary bugs were too tiny for me to perceive any detail with the naked eye (under 1mm big, but terrifyingly numerous). The infestation looked quite severe, and it seemed to have come on overnight. Some parts which were covered by dots had even turned a bit more yellow. I initially thought it must be mealybugs, but weird ones considering that they didn't have the usual furry fingery parts of the mealybug showing - but I supposed that perhaps there were weird strains of mealybugs in Britain - I mean, I'm not a mealybug expert! Who knows what the british mealybugs might be up to!

Most normal humans might consider throwing out their shockingly diseased-looking potted plant at this stage, but I decided that I was not going to do the normal thing. NO! I decided that I couldn't allow this plant to be eaten by mysterious white dots without trying to understand what was going on, so I googled for the instructions on how to eradicate mealybugs from a plant.

Techniques recommended included controlling the infestation using the mealybug's natural predators such as ladybirds or green lacewing. I considered going to the park and picking up as many ladybirds as I could, but I don't think George would want our bathroom to become a flying ladybird habitat (furthermore, we don't have the pleasure of having the time to breed flightless ladybirds which need to be bred by selective breeding like the Japanese have done).



Ladybird Transportation

To be fair, I'm quite sure if I needed to, I could actually find a handful of ladybirds and bring them home. Some are flighty, but some are quite tame and patient and will allow you to carry them for unreasonably long periods of time. This was a ladybird which I recently carried from a hot, uninteresting concrete pavement near Forest Hill - all the way to the very top of Crystal Palace Park...

Anyway, I had to go with a rescue method which involved MANUALLY CLEANING THE PLANT, LEAF BY LEAF WITH A COTTON SWAB DIPPED IN 70% ISOPROPYL ALCOHOL.

If I could give everyone a strangely philosophical warning on the sheer tedium of houseplant treatment, it would be this:

EVERY LEAF HAS TWO SIDES!
CONSIDER THIS BEFORE STARTING ON THE UTTERLY FOOLHARDY QUEST
OF CLEANING EACH LEAF OF YOUR POTTED PLANT WITH A COTTON SWAB!!!

After I spent ages cleaning each side of each leaf of the Dragon Tree, it looked much better. I was convinced it would survive this infestation of mysterious white dots.

Crucially, I also took a leaf from the bin and examined it with my USB microscope.





WHAT IS THIS??? THESE AREN'T EVEN MEALYBUGS!!!

For comparison:

MEALYBUG PICTURES


SCALE PICTURES


Looks like it is actually a kind of scale insect, a limpet-like creature which sits on plants and sucks the sap out of your poor juicy houseplants. How on earth did it get into our bathroom? The bathroom with its window mostly closed? I don't even know...

On an aside, I also wonder how many other people were induced to purchase plants on the NASA Clean Air Study list like me. Did the release of the list increase the sales of those specific plants, or are people not logical like that when it comes to their choice of houseplants?...

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