Is there any such thing as a non-target species

[Michael Gochfeld]

I was intrigued by Paul Cherubini's  response to my posting regarding 
West Nile Virus and malathion spraying. 

First an update.  Last night, Westchester County (southeastern New York 
State adjacent to New York City) announced a weeklong plan to spray the 
entire northern part of the county based on the finding of some dead 
crows (numbers yet to be reported). 
	The crow deaths have not been confirmed to be due to West 
Nile-like virus. 
	Moreover, even if dead crows are antibody positive, it is not 
confirmed that they died of the disease. 
	
	  We were in northern Westchester  last night and actually found 
two mosquitos in my parents house.  However, the total mosquito 
population this summer has been far below normal because of the drought. 
	Moreover, there have been no human cases of encephalitis in 
northern Westchester.
	So the widescale pesticide spraying is in response to crows that 
have died of still undocumented cause(s). This is not a rational public 
health activity. 
=========================================================
Now my response: 
I wrote  "It is not surprising that those interested in lepidoptera 
should > be appalled by the broadcast "mosquito control" spraying 
programs. > However, we should also make it clear that it is not simply 
the relative > value of controlling mosquitos vs preserving all the 
non-target species."

Paul responded: Where are the thousands of carcasses of the non-target 
species Mike?  

My observation: Malathion is NOT mosquito specific.  The dead non-target 
species have the same status as the dead mosquitos= undocumented. 

	I understand that there are indeed fewer mosquitos after the 
spraying than before the spraying.  Whether this is due to the spraying 
or represents the natural phenology of mosquitos has not been stated nor 
studied.  There have been no attempts to survey insects other than 
mosquitos. 


Paul also wrote: "Millions of people live in New York City. Dozens of 
amateur lepidopterists. Hundreds of butterfly enthusiasts. 
How come the only report of several dead butterflies comes from a lone 
jogger? Is this adequate evidence of a "massive" monarch butterfly kill 
in one of the largest metropolitan areas of the world?"

My observation: "There is no further information on dead Monarchs to my 
knowledge.  This year the NY-NJ area (and perhaps a larger area) has 
seen the largest Monarch migration in recent years.  I don't think 
Monarchs are the issue.  Malathion is pretty good at killing adult 
Monarchs.  Lots of Monarchs would have passed through areas that weren't 
sprayed or would have passed before, between, or after spraying, so a 
migratory species like the Monarch is probably not important to the West 
Nile-pesticide discussion.

I wrote: > There are two issues that should be addressed:
 
> 1. Risk: someone has alread mentioned that this so-called epidemic
> represents very few cases or deaths.  

Paul responded: Risk to what? What non-target organisms of value have 
been killed by the Malathion spraying?  

My response:  This is a very important point.  Who studies non-target 
species.  In this case a non-target species would be anything other than 
mosquitos (in fact anything other than Culex). 
	But more importantly, what does it mean to have non-target 
organisms "of value".  How would one define non-target species of "no 
value".
  One implication is that Monarchs have value because they can be bought 
and sold. 
	One would have to be very nihilistic about ecology to assume 
that nothing other than Mosquitos (and perhaps Monarchs) have value. 
	Does value only apply to dollar value (something that can be 
bought and sold?  This is not what I learned in Ecology 101. 
	The implication that one would have to define the value of every 
species is an argument that has been voiced against preserving 
biodiversity per se.  David Ehrenfeld argued persuasively that economic 
value is the wrong way to approach biodiversity. I agree. Value should 
be defined ecologically (certainly a difficult challenge). 

My next point> 2. More importantly.  The emphasis on broadcast spraying 
(which is > likely to be relatively ineffectual) 

Paul's response: Ineffectual? If  Malathion doesn't adequately kill the 
target mosquitoes very well, what basis is there to believe it will kill 
significant numbers of non-target insects of value?

Malathion could be completely ineffective against the target mosquitos 
if they are already indoors (in the houses where they can bite people at 
night).  In the Romanian epidemic of West Nile (1996) the presence of 
mosquitos indoors, was a major risk factor for infection (time spent 
outdoors was also somewhat important). 
	At the same time malathion could kill non-target species 
(including outdoors mosquitos and many other insects).  Malathion is 
still a pretty good insecticide.  So it could be ineffective in 
controlling the so-called "epidemic" yet damage non-target species. 

I then went on to say that the emphasis on spraying leads people to 
ignore the truly > effective ways of preventing themselves from being 
bitten by mosquitos > which involve control of breeding places 
(elimination or treatment of > standing water), screens, repellent, and 
staying away from mosquitos.

Meanwhile, I read that the CDC (the Federal epidemiologic agency which 
is the premier infectious disease prevention agency in the world) 
recommends the above procedures rather than widescale spraying.  
However, CDC wrote that the message for controlling mosquitos locally is 
being broadcast on radio and television. 

	This is certainly true on some stations and channels (the 
Westchester Cable channel carried good coverage of how to control 
mosquitos in your yard and home).  Philadelphia television also had good 
coverage (they don't have the virus and arent spraying).  However, 
network television in New York IS NOT CARRYING THIS INFORMATION.  It is 
only providing information about spraying and sometimes mentions staying 
indoors during spraying. 

Paul asked: Have these control measures ever proven to be practical or 
truly effective in an urban or other public health setting? Thousands of 
New Yorkers can't afford insect repellent let alone a place to live and 
sleep that has screened windows.

	Yes, these control measures are widely used throughout the 
world, especially in urban areas. Some more aggressive measures (like 
pouring oil on bodies of water) may not be ecologically desirable, 
but are certainly effective.  But many countries can't afford to do 
frequent spraying for mosquitos, and the efficacy of controlling 
mosquitos with spray, has been in question for 40 years.

	I was in charge of an infectious disease control program in a 
province in Viet Nam and we tried a several approaches to controlling 
diseases in refugee camps to control Malaria (mosquito) and Plague (rat 
flea). 
	Aerial spraying with DDT did not reduce rat flea counts (but we 
did find some convulsing rats), it did cut down briefly on malaria 
dissemination, but had to be repeated.  Eliminating mosquito breeding 
places was the most effective, followed by dusting of house walls with a 
mixture of DDT and talc.  We also taught people how to make their own 
rat traps out of bamboo (very clever design).  They caught lots of rats 
that were surveyed for fleas and for plague).  Once the villagers got 
into it, removing the rats played a significant role in breaking our 
plague epidemic.  The powers that be stopped authorizing spraying.  
 
	To say that thousands of New Yorkers can't afford insect 
repellent is not responsive to anything I said. And I doubt that the 
mosquito control is being done to protect the homeless people which are 
indeed a social and economic problem in New YOrk.  If that were the case 
we wouldn't see so much spraying in affluent areas of Queens, for 
example. 

I concluded > 3.  The notion that spraying insecticides on a broadcast 
basis is innocuous...

The response was: 
A bottle of chlorox contains chlorine - a powerful chemical that will 
kill almost any living creature undiluted out of the bottle. Yet most of 
us have no problem knowing chlorine is in all our tap water - the water 
we drink, cook and bathe in and the water we use in our butterfly 
gardens. We know from decades of practical experience that the dose 
makes the poison in the case of chlorine. Ditto for Malathion.


I would agree with this.  As long as malathion is in the bottle, I have 
no doubt that it is innocuous.  I have a bottle myself which I reserve 
for special occasions and use for spot applications.  It remains 
effective when applied judiciously and infrequently and safe when it 
resides in a bottle in my pesticide cabinet. I also take personal 
protective precautions when I apply it. 

Paul added:   After 4-5 decades of mostly successful use in public 
health pest control, we know low doses of Malathion broadcast from the 
air that are sufficient to kill target dipterans will not harm 
significant numbers of non-target insects or other wildlife of value.

	I personally don't know that this can be substantiated.  
Malathion is a pretty broad spectrum organo-phosphate which in high 
doses can effect humans.  In our occupational medicine clinic I have 
diagnosed humans with excessive exposure to malathion (some might even 
call it malathion poisoning) based on lowered cholinesterase levels.  
But it is true that the dose that kills vertebrates is higher than the 
dose that kills insects. So it should be possible to achieve an 
application that kills insects without killing vertebrates.  
	However, since the vast majority of Dipterans are non-target in 
this case, I don't think the statement is correct that it would kill 
"target dipterans" without harming significant numbers of non-target 
insects. The evidence isn't there.  

	Paul concluded: Virtually all lepidopterists have years of 
practical working experience with chlorine and do not fear it. But very 
few have years of experience with Malathion. We fear things we don't 
know about.  For example, I would be nervous going on a tour of a 
nuclear power plant even though I can see hundreds of people working 
there safely.

	Actually, very few lepidopterists have much experience with 
chlorine itself (a highly toxic gas that is one of the main causes of 
large scale human evacuations).  We do have experience with chlorox, and 
don't fear it. Most of us don't fear chlorine in our drinking water (we 
don't have it in our well water).  I don't think many people fear 
malathion either.  It's not the fear, but the irrational basis for 
applying it that I objected to. 
	But not to worry, I also visit nuclear power plants (as part of 
my job) and recently conducted an inspection tour of a nuclear reactor 
that was in the process of being "cocooned" (a neat technical term for 
sealing up the core completely to contain the radiation for a period of 
at least 75 years). 
	By using the term "cocoon"  the radiation safety specialists 
must be thinking that in the next century the radiation will emerge as a 
beautiful moth.  

Michael Gochfeld