Portrait of a mosquito, emerging from her pupa. Laboratory culture at Rockefeller University

Portrait of a mosquito, emerging from her pupa. Laboratory culture at Rockefeller University

(Sorry. My keyboard is suddenly missing letters.)  But I must write about mosquito spraying.  There is dengue fever in town.  And the city is spraying heavily, thinking this will solve the problem.  I’m no biologist, but I notice that the early results seems to be a sudden increase in mosquitoes, perhaps due to a vanishing of dragonflies, their best predator.




 When we arrived (early September) the dragonflies were plentiful  around our pool, probably because they were attracted by the scent of water during a drought.  (They consume huge numbers of mosquitoes, and are a good sign of control.)  The city sprayed in early October, and suddenly the dragonflies were gone. Then the mosquito population exploded.  (Immediately after the spraying, the pool surface was littered with dead mosquitoes; but I saw no dead dragonflies.)  However, I’ve seen no living dragonflies lately.  Yet absence of evidence (of dragonfly corpses) is not evidence of absence, so I can’t claim the spraying killed the dragonflies. Yet, the mosquitoes are worse than ever, and I’ve not seen dragonflies lunching lately. 

The problem with poison is that it kills indiscriminately, and won’t quit: mosquitoes, dragonflies, bats, people(?) — yes, it’s toxic to mosquitos, but perhaps not wise, especially if it executes natural predators doing a good job for free. 

The spray truck went down our street tonight, twice.  (I know the city cares about the citizens and tourists, but they may have a mistaken notion of how to fix this problem.) I immediately closed our windows.  Worse, this morning I had noticed that a neighbor has an old concrete tinaco without a lid, and there is a foot of water in it, which I saw by tiptoeing across their roof.  I wonder how many of these failed structures are hatching little bloodsuckers in this town while we sleep? Look up!  

¿Best control, no toxicity to us:


Amazon de|ivers some products to buyers in Mexico, but I’m unsure about dunx.  I suggest reading the reviews at Amazon.  I’ve used this product for the past two years, and am impressed, but have done no scientific assessment.  My experience is that the first year it controlled for larvae beyond my imagining. Year one, our property manager had tossed a dunk into the pool at least once per month.  When we arrived in September 2014, I found no presence of larvae whatsoever.  (The pool had been drained before leaving in April, but had accumulated some rainwater and leaves; it contained no pool chemistry.)  I entered the pool wearing boots and shorts, no camisa. I didn’t get bit even once.

This year, under the same regimen, some larvae were present.  The product, which contains a biological aspect called bacillus thurengensis israeli, would appear to have a shelf life. But maybe the presence of dragonflies had kept the population low. And the bats help in the evenings. (Bats are notoriously susceptible to pesticides, and we’ve also seen far fewer of them in October than we did in September, before the spraying.)  

Full disclosure: I have no commercial interest in the dunks product.  I am merely a customer (and a Vine Voice reviewer) at Amazon.  But I was not invited to review the dunks product, finding it on my own.