Read and follow label directions…

Every extension specialist or educator that mentions any kind of pesticide in a talk or article always includes the disclaimer ‘Read and follow all label directions.” However that caveat ranks somewhere between “Your seat cushion may be used as a flotation device” and “Do not remove tag under penalty of law” as the most ignored phrase in the English language. While we can probably rationalize ignoring the last two (If a jetliner ditches in the middle of the Atlantic is a seat cushion really going to save you? And when was the last time you saw someone led away in handcuffs for pulling the tag off a mattress?); failing to pay attention to pesticide labels can have some real and immediate consequences.


I got called recently to inspect some tree and shrub damage at an industrial park in suburban Detroit.  (Because the case potentially involves some legal issues, I won’t mention names of any parties).  The industrial park included several hundred acres, much of it turf and landscape beds of trees and shrubs.  The park had its own groundskeeper but contracted out its spray applications.  A couple summer’s ago the staff groundskeeper complained several times to the contractor that they weren’t doing a sufficient job of keeping up with the weeds in the landscape beds.  The typical vegetation management tools of choice on this site were spot applications of Round-up (glyphosate) and hand-weeding.  For reasons that are not completely clear, this time the contract applicator reached for a jug of Sahara.    Even if you don’t know what Sahara is; what image does the name conjure up?  Parched. Barren. Lifeless.  Sahara is a combination of two herbicides (Diuron and Imazapyr) designed for complete vegetation control in non-cropland areas such as parking lots and rights of way.  And, unlike Round-up, Sahara provides foliar and root activity.  This is a product you use when you want complete burn-down and you don’t want anything growing there for a long time.


A hedge maple 2 years after herbicide application

Unfortunately, that was not the desired result in this location.  Within a week of the application, dozens of trees and shrubs all over the industrial park were either dead or wishing they were dead.  The smoking gun was not too hard to find.  The applicators had duly noted the herbicide application in their logbook and presence of active ingredient was confirmed in soil samples.  Although the parties are still working a settlement, the bids for replacing the affected trees and shrubs are well into six figures.


The unkindest cut of all.  These green ash were regularly treated with imidacloprid to protect against emerald ash borer.  An herbicide ap took them out instead.

Two years after application there are still bare zones where Sahara ran off from mulch rings and landscape beds.

Of course, all of this death and destruction (and legal wrangling) could have been avoided simply by…  Reading and following the label directions.  The Sahara label notes in several places that contact with roots can damage trees and other plants, including this explicit statement under a heading in all bold letters, PRECAUTIONS FOR AVOIDING INJURY TO NONTARGET PLANTS:  “Injury or loss or desirable trees may result if Sahara is applied on or near desirable trees or on areas where their roots extend.”  Sounds pretty clear to me folks – don’t use this stuff near plants unless you want them to die.


So, next time you or someone working for you has any question about what a pesticide does:  Read and follow label directions….

Bordeaux Mix

One of my favorite stories about pesticides is the story of Bordeaux mix.  It’s a story of France in the 1800s (so it must be pretty romantic, right?) and how they were suffering from a shortage of grapes.  Don’t feel sorry for them — it was really their own doing.  Over the course of the 19th century grape vines were brought from the United States to test their merits against European grapes.  It was quickly discovered that, for the most part, American grapes were not the equal of European grapes for winemaking.  Unfortunately for the French, however, along with the grapes came a disease: downy mildew.  This mildew absolutely ravaged grape vines across Europe, and particularly France from the time that it was introduced, around 1878.

Meanwhile there was another problem for grapes growing in France.  People.  People like to eat grapes beside the side of the road and so, throughout France’s grape growing regions, grapes on the sides of the road were typically bare.  Unlike downy mildew, however, grape growers had a pretty good idea what to do about people.  They sprayed nasty stuff on the grapes.  This nasty stuff took many forms, but the one which was most effective was a mixture of copper sulfate (basically you dissolve copper in sulfuric acid) mixed with lime.  Brushed on a plant’s foliage, it was darn ugly.

Then came 1882; a terrible year for downy mildew.  Grape vines were losing their leaves all over Europe, except for those vines beside the sides of the road.  There the grape vines were doing just fine.  The reason was the copper in the lime/copper sulfate mixture which was eventually dubbed Bordeaux mixture because of where it was first used.  Bordeaux mixture is still available today, and is one of the most important tools in the organic grower’s pesticide arsenal.  Unfortunately it’s nasty stuff – it builds up in the soil and it’s toxic to earthworms and a wide variety of different plants and aquatic organisms.  Using this stuff once in a while – such as once a year – isn’t terrible, but regular use is a good way to ruin your plot of land.

One final thought – Those American vines which originally brought in mildew?  They eventually became very important to French wines because of another introduced pest, phylloxera.  They were used as rootstocks because they were resistant to this pest — unlike European grapes.

Bee studies, blogs, and biases

My original posting last Wednesday (“Ignorance and the so-called “bogus” bee study“) has generated some vigorous discussion, which is exactly what I hoped it would do. At some point, one of our readers posted the link on the original blog site, where it generated the following response:

“The issue on CCD and these studies that point to “causes” other than pesticides comes down to a question: What came first? The pesticides or the problem. Farmers almost always have the gut answer correct. In this case the farmers are the hundreds if not thousands of beekeepers who are certain that neonicotines are root cause of colony collapse disorder. I’m not a PhD, admittedly, but I’ve yet to read anything that points to an answer other than the pesticides.

“And for Linda to suggest that science can’t be “bought” at universities is an incredibly naive statement. I’m not saying Jerry was bought out, not at all. But I do think, overall, there’s a ton of pressure from the chemical industry for scientists to find an answer, any answer, that doesn’t point back directly to pesticides.”

I responded to this posting on the blog this morning, where it sat waiting for approval by the moderator:

“There are dozens of peer-reviewed studies on colony collapse disorder that can be easily accessed by anyone who is really interested in the science. Here’s a quote from a 2009 article:

“Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD.”

From “Colony collapse disorder: a descriptive study.”

Authors: Engelsdorp, D. van; Evans, J. D.; Saegerman, C.; Mullin, C.; Haubruge, E.; Bach Kim Nguyen; Frazier, M.; Frazier, J.; Cox-Foster, D.; Chen, Y. P.; Underwood, R.; Tarpy, D. R.; Pettis, J. S.

Available at:”

Then….it was deleted.

For whatever reason, the moderator of this blog didn’t want to post my response. So I’ve reposted it above, and have a couple of other observations:

1) “Gut answers” aren’t science. Sure, gut feelings can convince researchers to explore some particular question, but they are inspirations – not necessarily answers. As my husband pointed out, people once had “gut feelings” that the earth was flat and that the sun orbited around the earth. Enlightenment happens.

2) Let’s see some specific examples where science has been “bought” at universities. I’m sure there are a few bad apples (especially in pomology – HA!), but to my knowledge none of my colleagues have pandered to chemical companies and falsified data for publication. This is a serious charge – and if it’s true, we all deserve to see hard evidence.

As always, feel free to post YOUR comment. We won’t censor you, even if you don’t agree with us.

Dirty Dozen?

Nobody in their right mind considers pesticides safe.  They are, after all, poisons which we have created to kill things, be those things plants, insects, fungi, rats, or whatever.  The idea that we could have foods with no pesticides on them is attractive.  Now I’ve got to admit that, as a general rule, I don’t think that the levels at which most pesticides are found on foods is concerning.  Our methods of detecting poisons are just too sensitive today and so we end up saying that a poison is “present” on a tomato or whatever even if it’s there at a harmless parts-per-trillion level.  Still, I won’t deny that I’d prefer it if there were no synthetic pesticides on any food.

A couple of days ago a report came out from CNN about the “dirty-dozen.” This is a list of the twelve fruits and vegetables which are most likely to have detectible levels of synthetic pesticide residues.  Along with this list there is a suggestion that, when purchasing these fruits and veggies, you should select those that are organically produced whenever possible.  I don’t have a problem with this list being reported.  In fact, I think it’s a good idea to give people all of the information that we can about pesticides.  While I, personally, am not particularly afraid of conventionally produced fruits and veggies because of the synthetic chemicals which they may contain I appreciate the fact that others might be.  I do, however, have a major problem with the idea that organically produced fruits and veggies are necessarily safer than those produced with synthetics.  You see, organically produced food is not tested for residues of potentially damaging organic pesticides, and those same foods that are slathered by synthetic pesticides in non-organic growing systems are typically slathered by organic pesticides in organic systems, particularly if you’re dealing with foods produced using what has become known as “industrial organic production” which fill most of our large grocery stores with USDA Certified Organic Produce nowadays.  These organic pesticides may be present at higher concentrations than synthetic pesticides and may have similar effects on humans, and even worse effects on the environment than synthetics (though it depends on the exact pesticides used and how often they are used of course).

The myth that organic foods don’t have pesticides used on them is one that really needs to die.  No farmer, organic or non-organic, wants to use pesticides, and sometimes they can get away without using them.  Certain crops are rarely sprayed regardless of whether they’re produced organically or not.  Pesticides cost money and are dangerous, but when faced with the potential loss of a crop producers will do what they need to do to avoid losing their crop, and if that means applying pesticides then so be it.  Organic farmers may choose to use different pesticides, and they might wait longer before they spray (although often they spray sooner because the relative efficacy of their sprays are inferior to synthetic sprays) but let’s not say that organically produced foods are free of pesticide reside.  Just because we’re not testing for it doesn’t mean it isn’t there.

Do Organophosphates cause ADHD?

Ever since Monday’s post I’ve been preoccupied thinking about that article which was mentioned in the comments section by Daniel . This article basically summarized a study that seemed to show that ADHD in children was related to exposure to organophosphate insecticides.

Articles like this appear all of the time in mainstream media and they scare the bejezus out of us because, after reading them, we end up thinking “Holy crap! We’re killing ourselves and ruining our society with these insane chemicals!” Most of the time, however, this just isn’t the case.  Look, if everything that the papers reported about the negative effects of pesticides and other chemicals was true we’d all have cancer, mental illness, or we’d just be dead.

After the above you’re probably telling yourself that I’m some kind of maniacal chemical apologist.  Maybe I am, but I don’t think so.  I’ve spent a lot of time reading the actual articles from which these media pieces are written and I like to think I have a relatively balanced view of these chemicals – maybe I’m deluding myself though – I’ve been known to do that on occasion.  In any regard, what I’m going to do with this blog post is to take a look at the media article and let you know some of the questions that I want answered before I get very concerned about the research, and by answered I mean answered by the scientific article from which the media piece was derived.  Now, to be fair, I have not read the actual scientific article from which this media piece was derived.  It isn’t online as I’m writing this (at least nowhere that I can find it), though I have no doubt that it will be soon.  I suppose that I could have waited to write this until it came out, in fact I considered that idea carefully, but instead I thought that I would tell you about the things that I’m wondering about the article; In other words, the things that I’ll be looking for when I finally get to read it.  Media people want POW!  Scientists want to know what’s actually going on.

Before we begin I should tell you that I’m no fan of organophosphates.  They include a wide range of chemicals (though they are, obviously, all related in that they’re organic chemicals with phosphorus), some worse than others – from the relatively tame orthene and malathion to the scary-as-hell disulfoton (aka disyston).  Right now, as an extension specialist who works with growers, I can tell you that organophosphate chemicals are, in general, not a preferred choice for most growers simply because there are so many safer and more effective choices out there.  My feelings about organophosphates can best be summed up by what I wrote in my book The Truth About Organic Gardening “[Organophosphates] are an old class of insecticides that has served its purpose and for the most part should probably go the way of the dodo, with the possible exception of orthene and one or two others.”

So here we go, the things that I will be looking for when I read the actual scientific article:

1.  What’s the confidence interval?  In the media article it was stated that children with higher levels of organophosphates were about two times more likely to have ADHD, but no confidence interval was given.  In epidemiological studies such as this the likelihood of a given outcome is usually expressed as an odds ratio.  In this case the odds ratio that a child would develop ADHD given a high level of organophosphate exposure would be about 2 (because it would be 2 times as likely that a child would develop ADHD as it would be if the child weren’t exposed to the organophosphates).  But in a scientific article the odds ratio will always be coupled with a confidence interval.  A confidence interval tells you how confident you are in your odds ratio.  If you’re very confident then you’ll have a narrow confidence interval – maybe 1.8-2.2 — which means that it is 95% certain that the odds ratio is between 1.8 and 2.2 (the 2.0 odds ratio is basically just the most likely point on the confidence interval for the odds ratio to sit.  It’s kind of like, but not exactly the same as, an average).  For an epidemiological study that’s darn good.  If that’s the confidence interval present in the article then I’ll be impressed.  What we might find though is a confidence interval of something like 0.2 to 22.  That stinks and you’re deluding yourself if you think that a confidence interval like this “proves” anything – unfortunately I have seen plenty of media articles use research with confidence intervals such as this because of the POW! factor.  They ignore the confidence interval and just look at the odds ratio.  My guess is that this article has something in between the two confidence intervals which I listed above – we’ll see.

2.  I want to know how often urine was sampled.
Organophosphates move through the body very quickly.  In fact, I was recently reading a paper which showed that you can’t predict from one test time to the next what organophosphate readings will be because there’s so little consistency.  If you’re exposed to an organophosphate one day you may test high that day, but two days later you’ll be testing low again, so, I want to know if a single sample was done – which I would consider to be almost useless in terms of telling us actual organophosphate exposure – or if multiple samples were taken over time which I would consider to be much more useful.

3.  Did the organophosphate really come from food?  The implication that these organophosphates which, in theory, contributed to the onset of ADHD came from food bugs me.  I want to see if the author actually draws this conclusion in the paper or if it was made up by the media.  There are lots of places that organophosphates are and have been used, the singling out of fruits, vegetables, or any food seems ridiculous to me.  The author of the media article points out that organophosphates are not used around homes much – but that really isn’t the case and it certainly wasn’t the case just a few short years ago. There are still plenty of organophosphates being used quite regularly around homes.  I just did a search for orthene and malathion and found that I could buy them quite easily online.  Diazinon and chlorpyrifos are two others that shouldn’t be used by homeowners but which I know of people using – sometimes in heavily trafficked areas.

4.  I’d like to know about how the other potential contributors to ADHD were controlled.  There are other things that have been correlated with ADHD, how were these controlled so we know they weren’t the cause of the ADHD measured in this experiment?  For example, abused or neglected children seem to have a higher rate of ADHD, how was this taken into account in the study?  Was it taken into account?  A theory would be (and I’m totally making this up) what if abused children are fed more food with higher rates of organophosphates while non-abused children are fed more organic food.  Then the results would show that the neglected kids had higher ADHD and higher organophosphates – but was it the poor parenting or the organophosphates which caused the ADHD?

So, those are the four questions that I’ll be asking right off – and there are more that I’ll think of once I actually read the article.  All of these questions don’t mean that I think the article is bad though – regardless of what their answers are.  This research was probably well conducted and will enlighten scientists and lead to new avenues of research.  But, I’m willing to bet that the POW! from the media article (ADHD is caused by eating organophosphates on food) isn’t quite as powerful when the whole article is read with a more critical eye.

Dandelions and clover

It was fun to read all of your comments last week about your opinions on lawn care.  To follow up on it I’m going to talk a little bit about why I’m not fond of companies which apply herbicides multiple times throughout the year.  But first I think I’ll mention why I apply herbicides at all — aesthetics.  That’s it — the whole reason. Could I go the no-lawn route?  Yes, but I like having a yard to run in.  Not a huge yard, but a little yard to play tag with the kids.

What I long for though is the yard from the house that I grew up in.  Our house in southeastern PA (About an hour west of Philly and an hour east of Lancaster) was set back about 800 feet from the road and was on old agricultural land.  The area around the house was planted in grass in the mid 70s and then it was left alone.  Fertilized once the first year I think, but that’s it.  Dandelions invaded quickly as did clover.  Over the years the clover began to dominate the grass, but not to the point that the grass disappeared, and the lawn actually appeared relatively homogeneous.  Dandelions never left, but their numbers declined.  The clover grew low and the grass never shot up like it does in a heavily fertilized lawn and so mowings only happened once every two weeks or so (well, OK, sometimes more often depending on the weather and where on the lawn you were — the spot over the septic tank needed mowing every 48 hours or so).  The grass did go dormant most summers, but 800 feet from the road there wasn’t anyone to complain, and besides, the clover kept the lawn from appearing completely scorched.  The lawn looked good for well over 30 years (until my parents remodeled the house and the yard was torn up).

The typical suburbanite might not have liked this lawn, but to me this lawn looked great, and, besides, it was low maintenance.  The reason I’m bothering to tell you about this lawn though is because it illustrates so well what lawn care companies make impossible.  They say (and by “they” I mean professors like myself) that pesticides beget pesticides and fertilizers beget fertilizers, and nowhere is that as true as in a well manicured lawn.  The herbicide of choice is 2,4 D (though there are many others that are used) which lawn care companies apply multiple times over the the course of a year.  This pesticide does a great job of killing dandelions, but it also kills clover.  It rarely hurts grass unless it’s grossly over-applied.  The problem with killing clover is that this clover is the stuff that fed the grass in the house where I grew up.  Clover takes nitrogen out of the air and makes it available to grass every time the lawn is mowed (the clipped off pieces of clover degrade and the nitrogen in them feeds whatever plants are around).  Without the clover you need to add fertilizers.  So, because the lawn care company is keeping the lawn free of weeds they also need to fertilize because they’re killing all of the natural fertilizer.  Here’s the thing, the weed that most people in the suburbs like least, dandelions, is actually very sensitive to low potassium.  The lower the potassium in the soil the worse it does.  In fact, dandelions can easily be out-competed by grass and clover if potassium is low — just as happened in the yard of the house where I grew up.  But do lawn care companies pay attention to this (by using high nitrogen, low potassium fertilizers?)  What do you think?

My guess is that many of you thought that I’d cite all kinds of scary side effects of the pesticides used on lawns.  Nope.  In general I think that, if used properly, they’re pretty safe for humans (with a few notable exceptions).  I’ve spent a lot of time reviewing epidemiological and toxicology studies and I can think of many worse things.  I am somewhat fearful of what 2,4 D may do to dogs in particular — they can’t excrete this poison like we can.  Don’t think for a minute that I’m calling these poisons perfectly safe — I just think there are plenty of other better established reasons to avoid lawn care company pesticide schedules.