jeffgillman003

Scrambling for Answers

Yesterday a good friend of mine who works for a well respected tree company in town asked me whether I would be willing to talk about tree conservation as it relates to the emerald ash borer. Specifically he wanted me to make people aware of a statement produced by a group called the Coalition for Urban Ash Tree Conservation which you can find here which was produced by a number of well respected industry people and academics. This statement basically says that we shouldn’t cut down all of our ash out of fear of the emerald ash borer but that we should, instead, treat some with various insecticides to conserve our ash.

I don’t have any major disagreement with the article, but it’s important to remember that every situation is different and that, while chemical treaments might be appropriate for one ash, another should hit the chipper. As the emerald ash borer moves across the country we’ve got to assess what our ash are worth to us and decide when and where it’s appropriate to save them. This is an extremely daunting task without easy answers. The statement by the Coalition for Urban Ash Tree Conservation is good and very appropriate, but what would be even better is a guide to help people decide whether to leave trees alone, to cut them down, or to treat including all of the costs and consequences.

UPDATE: As you might have expected, there is already a cost calculator out there — I just wasn’t aware of it. Fortunately Katie was and left details in the comments section. If you are interested in a calculation to figure out the cost of treating vs. removing ash go here http://www.ag.purdue.edu/entm/Pages/csadof.aspx and then click on EAB cost calculator — it’s on the left hand side. It’s a very nice little tool!

Porsche 911 or Toyota Camry

Earlier today I was in a meeting with some other professionals from across Minnesota (and a few from Wisconsin and other areas) to discuss the disease problems of conifers. Our discussion quickly became focused on the use, and overuse, of Colorado blue spruce, a tree that just doesn’t do well in Minnesota — Or Michigan from what Bert has written! Everyone in the meeting was yammering on about how we need to educate nurseries and consumers about how terrible the Colorado blue spruce is in our environment — you’re lucky if you can get 10-15 years out of the thing before it succumbs to one disease or another. But, though academics, arborists, and most tree care professionals (including nurserymen) talk about how lousy this tree is, customers want Colorado blue — and if a nursery doesn’t sell it, well then that nursery has lost some business.

I support the idea of warning people away from Colorado blue. Still, during our meeting I couldn’t help but have this thought running through my mind:

Colorado blue spruce is a unique and beautiful tree — it is bluish in color, tends to have a good form, and is a relatively fast grower (until it succumbs to whatever disease it dies from!). There are certainly other trees that are also beautiful — but there is no denying that Colorado blue has a distinctive look. If I were walking through a nursery this would be the tree that I’d want. If a nursery person told me that the tree was going to have a short life — 10 – 15 years of looking good — I just might be OK with that because there just aren’t that many trees which look as attractive as a Blue spruce in a nursery. Sure, I could have something that would look OK for 30 years, but, if I’m like most Americans, I won’t even be in the house that I’m living in now in 10 years, never mind 30.

To draw an analogy, You know that a Porsche 911 isn’t the best car to buy — it is a gas guzzler (for it’s size) — it doesn’t have much luggage space (or room for passengers), and it’s less reliable than your typical compact car. A Toyota Camry is better in all of the areas that I just mentioned. Still, if I were looking for a car and if they were the same price I have to admit that the Porsche would be too cool to pass up.

Where to Draw The Line on Home Remedies

On Tuesday Holly posted an extremely interesting article about how Bounce could help control fungus gnats. Then one of our frequent commenters (and all around great guy) Ray Eckhart pointed out that he has a problem with promulgating an off-label use of a product. And that got me to thinking. What household products is it OK for us to suggest that a consumer use for a non-labeled purpose, and what products shouldn’t we suggest? This is a question that has haunted me for a long time, so with this post I want to give you my line of thinking – I’m not trying to tell you what’s right or wrong – just trying to let you know my thoughts on the topic.

First of all, let’s admit that there are off-label uses of products which most of us hardly think about and simply accept as “generally OK.” For example, I have never been taken to task for suggesting using a plastic bag for protecting fruit from insects or for suggesting that dish washing detergent may be a good insecticide. Of course both of these pest control techniques have their drawbacks (it can get hot in the bags in the South, injuring fruit, and insecticidal soap can burn the foliage of sensitive leaves) still, using these products outside of their labeling doesn’t seem to bother people too much. Likewise, the idea of using alcohol to stunt plant growth, eggshells to stop slugs, or milk to control plant disease doesn’t seem to upset people too badly (whether they work or not being beside the point).

But there are some off-label uses of products which could be considered obviously bad. For example, controlling weeds by dumping gasoline on them and setting them on fire, or perhaps washing your ripe fruit in a cup of paint thinner.

Then there are the off-label uses of products such as mouthwash for plant disease and tobacco juice for insects. I see these as neither obviously fine nor obviously terrible. So where is the line to be drawn?

In my opinion, as an extension educator, I feel that it is my job to tell my audience (That’s you guys!) the facts about different gardening/growing techniques including those that are “off-label.” I don’t feel that it’s my job to tell you what to do and what not to do (well…maybe with the exception of telling you not to pour gasoline on your weeds and light them on fire or not to soak your food in paint thinner!) It is up to you to make your own decisions.

Let’s go through a “for-instance” here. And let’s use one that I’ve written about – using hot peppers as an insecticidal spray. Hot pepper sprays can work to control certain insects. Just mix up a few hot peppers with some water, add some dish detergent, put it into a spray bottle, and off you go. I have used sprays like this myself in small experiments to control mites, and they have worked reasonably well. I have also read a number of articles showing that these sprays have at least some effect on certain pest insects. But hot peppers certainly aren’t “labeled” for use against insects, and let me tell you, a little hot pepper in the eyes, or even the skin, and you can be in pain for hours. Long term damage is unlikely – but not impossible. So what should I, as an extension educator, do? In my opinion exactly what I just did – give you the facts and let you make your own decisions. I feel exactly the same way about Holly’s post about Bounce – she gave you the facts – if you want to try using Bounce to control something then that’s up to you. Do I recommend Bounce for controlling insects? No. But I’m the kind of person who encourages careful experimentation, so I wouldn’t tell you not to use Bounce to try to control insects either – though I would tell you to be very careful and that unintended consequences might arise.

One To Go!

Just one more little holiday to go over holiday week (A week during which faculty at UMN were put on furlough — in other words unpaid vacation), but for many of you I’m sure it’s a big one: New Years. I’ve never been one for New Years resolutions. It’s always just seemed kind of artificial to me. Still, some people find real motivation with the passing of a new year. What about you? Any great New Year’s resolutions out there related to gardening?

Unintended consequences

Unintended consequences. When doing one thing causes something you didn’t expect. Many unintended consequence stories in biology start with introduced species. I’m going to skip those here. I’ve been thinking about unintended consequences recently while trying to figure out what to do about my hops. You see, hops have a nasty habit of getting powdery mildew. That’s one reason why you don’t see a whole lot of hops growing outside the relatively arid Yakima Valley (75% of US production). We started research on hops this year in relatively un-arid Minnesota, and I don’t want our plants to succumb to the dreaded disease. Because we’re growing varieties that don’t have a lot of resistance, and we can eventually expect to get the disease in this environment, I want to develop a way to manage it effectively so we can still do research. But how do we avoid powdery mildew? A lot of growers use weekly applications of sulfur. It’s a nice fungicide for this purpose, and it’s pretty cheap compared to synthetic fungicides. Great, sign me up for that! Oh by the way, using sulfur early in the season may cause more spider mite problems later in the season compared to using other, more expensive fungicides.¹ Oops, unintended consequence.

One of the most famous examples of unintended consequences that I can think of (OK, other than DDT and birds, or introduced species) is from hybrid field corn 40 years ago. Detassling corn for hybrid seed production is a hassle, so a modified corn was developed that didn’t produce pollen. Cytoplasmic male sterility, this technology was called. Perfect! No need to hire droves of unskilled labor to walk every acre of seed corn production fields. Except it turns out that a side-effect of that particular modification made corn especially susceptible to southern corn leaf blight, which damaged a large amount of the corn crop in the early 1970’s. Unintended consequence.

Imagine the florist’s carnation. It’s that flower in shades of white to red that you see on boutonnieres and corsages during homecoming and prom, or alternatively, that flower dyed green for St. Patty’s or blue to match Grandma’s hair. Before breeding for increased longevity / vase life, carnations had a noticeable smell. When breeders ignored fragrance, or possibly even unknowingly selected against fragrance (fragrance may decrease flower longevity), they made carnations that are just kinda pretty looking, and that’s about it. Unintended consequence. Now researchers are trying to figure out how to get fragrance back into flowers (and even into flowers that never had much in the first place).²

Here I will steal from a somewhat confusing speech of recent past, and turn it into somewhat confusing text to fit my story. Unintended consequences are usually a result of ‘unknown unknowns’. We don’t know even know what questions to ask (“Yes, I’m using sulfur to kill powdery mildew. So what?”). Turning an ‘unknown unknown’ into a ‘known unknown’, or something that we know we don’t know but can hopefully find out, takes an open mind, a keen eye, and creativity. Like “hey wait a minute, now that I’m using sulfur on my hops, I seem to have more problems with spider mites. I wonder if there’s a connection…” That’s still unknown, but at least it’s a ‘known unknown’. Turning a ‘known unknown’ into a ‘known’ takes science, and making it widely ‘known’ takes people who keep up to date on science and are good at writing or speaking. Hooray for research and extension!
¹ Gent et al. 2009. Effects of powdery mildew fungicide programs on twospotted spider mite, hop aphid, and their natural enemies in hop yards. J. Econ. Entomol. 102(1):274–286.
²Vainstein et al., 2001. Floral fragrance: new inroads into an old commodity. Plant Physiol. 127(4):1383.

Bees and Pesticides

I had the opportunity to read a disturbing post over at Garden Rant the other day about the insecticide clothianidin and how the EPA required its producer, Bayer, to run tests on the safety of using plants grown from seeds treated with clothianidin for bees. Tests which were, apparently, never carried out appropriately. This post sent me over to another site, AlterNet, which explained the problem in detail. In a nutshell what happened is that the EPA asked Bayer to run some tests on how its new pesticide might affect bees. Bayer was unresponsive at first, but eventually did run some tests (which were not what you would call robust) which showed that bees did fine when flitting around in a field of plants which came from clothianidin treated seeds – at least for as long as the test was carried out.

Then one of our commenters asked for our opinion, and heaven knows, I am always more than happy to offer my personal opinion! So here it is. I am extremely unhappy with both Bayer and the EPA in this instance. They didn’t do what they were supposed to do. It’s as simple as that. Tests were supposed to be run to demonstrate that it is unlikely that clothianidin affects bees. This wasn’t done in a reasonable period of time. Period. As long as stuff like this occurs nobody is going to trust the EPA or the chemical manufacturers. In terms of whether the tests were sufficient (basically some hives in a field of treated plants), well, I would have liked to have seen more depth, but they didn’t seem to be bad studies.

The implication is that, because we don’t have enough testing, clothianidin could be causing bee colonies to collapse. This goes hand in hand with the suspicion that imidacloprid is leading to colony collapse since both of these chemicals are neonicotinoids. We know that these pesticides can get into flowers where bees come into contact with them. The question is whether the bees contact enough to cause hives to collapse (There is no question that these chemicals, at some level, are poisonous to bees – just as almost anything can be poisonous to humans at a high enough dose – even water).

One thing that is lost in this discussion is that SEED TREATMENTS were being examined. A seed treatment is when the seeds which are planted are treated with a pesticide (in this case clothianidin) to protect the seed itself and the young plant from insects. As the plant grows the insecticide will break down and become diluted – And so it is probably not going to be present at high levels in pollen that the plant (which comes from the treated seed) produces. Still, there is potential for this to happen and so it is best if the plants which come from the seed are tested – hence the EPA’s request.

Historically, there are pesticides which have clearly and unambiguously lain waste to bee hives, the most infamous of which was Penncap-M. This was a unique pesticide because it was a microencapsulation of the very dangerous insecticide methyl parathion. The microencapsulation process made this pesticide last longer, and made it somewhat safer to handle, but it also made the pesticide into tiny little beads – about the same size as, you guessed it, pollen. In fruit trees in particular this stuff would become attached to the bees (just like pollen does) and you can imagine the disastrous results. The answer was to limit the use of this poison to certain times of the year and certain situations when bees were not likely to be around. Why wasn’t it just banned outright? Because it worked well and, when used appropriately, it didn’t affect bees (Here I’m giving you the official line – In my opinion its use should have been even more restricted than it was). Penncap-M is not closely related to the neonicotinoids chemically, though it does affect insects’ nervous systems as many insecticides, including the neonicotinoids, do.

You can count me as one of the people who suspect that the neonicotinoids have something to do with colony collapse. I’m not a bee researcher — but it is easy to see how the use of these chemicals might weaken a hive to the point where mites or disease could come in. One of the things that drives me a little nuts though are those people who think that banning neonicotinoids is going to save our bees. It seems quite obvious at this point that these chemicals are definitely not the sole cause of the disease and perhaps not even one of the major contributing factors. They essentially banned these pesticides in parts of Europe, and guess what? They still have bee colonies collapsing. An interesting side note is that historically large-scale losses of bees isn’t as odd as we might think – in fact, we might have seen this disease (CCD) before. Perhaps even in the 1800s. In short, it seems that the answer to this problem is not as simple as banning some pesticides (though restricting their use may be a piece of the solution). I wish it were.

Of Worms and Fertilizers

Today I’m going to write about fertilizers and worms. The purpose of this post is not to encourage you to use fertilizers. I agree wholeheartedly with Linda’s post – we don’t need many of the fertilizers which we’re using. Still, it’s important to know the facts about anything that you’re doing (or not doing) to and for your garden, and to do them (or not do them) for the right reasons. With that in mind, I’ve been reading about worms and fertilizers for the last few days and wanted to let all of you know the basics of what I’ve been reading, because it is somewhat contrary to what many gardeners believe.

Before we begin let’s get one thing straight — worms are basically good for your garden and your plants in general. We like them!

Over the years I’ve heard all kinds of comments about how inorganic fertilizer is bad because it kills worms or drives them away. For the most part I’ve just accepted these claims as generally true because it seemed to make sense and I didn’t have a reason to study it further (I don’t write about worms much, and I’ve never spent any time doing research on them – still, I have to admit that this is no excuse for ignorance). The only contrary words I’d ever heard spoken about the reality of what fertilizers do to worm populations had come from a soil scientist friend of mine who told me, in casual conversation, that he didn’t believe that fertilizers were bad for worms at all, except, perhaps in the very short term if they got some fertilizer directly on them. Rather, he believed that, because fertilizers encouraged the growth of plants, fertilizer use would actually increase worm populations because it would increase their food supply.

After reading through a few papers it looks like my soil scientist friend was right. Here I’m going to summarize my general impressions about these papers into a few sentences – not exactly fair because the relationship between worms and fertilizers isn’t completely straightforward – but hey, this is a blog! Basically, if you add fertilizer of any sort to your soil you will ultimately increase worm populations because you will encourage the growth of more plant material. More plant material, over the course of time, means more organic matter for worms to eat. Generally organic fertilizers seemed to be preferred by worms (probably because they include lots of organic material along with the nutrients which they offer), but overapplication of fertilizer (organic or inorganic) could be bad for worm populations, at least in the short term.

So, in a nutshell, judicious fertilizer use shouldn’t affect worm populations negatively. Still, why add fertilizer at all if you can avoid it? Mulch and compost – worms will definitely enjoy that!

Balanced fertilizers are usually out of balance

I’m in the midst of grading papers for my nursery management class, and something that I’m running across is an incredible number of papers where the students are recommending balanced fertilizers. Why are they doing that? Or maybe an even better question is, what is a balanced fertilizer? A balanced fertilizer is a fertilizer which has three numbers which are about the same, like a 10-10-10. The problem with balanced fertilizers is that they are much higher in phosphorus than what most plants need — at least in relation to the amount of nitrogen and potassium which plants need. Especially here in Minnesota, where there is usually plenty of phosphorus in the ground, this extra phosphorus serves no purpose except to pollute waterways. We have got to break the cycle of just assuming that a balanced fertilizer is the way to go. I get to see a lot of soil tests from old agricultural fields where balanced fertilizers were used for years and years. Usually 10-10-10. What I usually see — with very few exceptions — are phosphorus and potassium levels which are either very high or off the charts entirely. Phosphorus and potassium don’t move readily in the soil while nitrogen does, so every year that you add 10-10-10 in the appropriate amount for your plants needs for nitrogen you’re adding too much phosphorus and potassium. Any extra nitrogen which you add will move through your soil, but P and K will build up year after year (and some will run-off into gutters and drains). So what do I recommend? I like a ratio of about 5-1-2 or 5-1-3 for an N-P-K ratio in a general use fertilizer.

DMSO

A few months ago I was interviewed for an article where they asked me whether I thought that a deer repellant which was taken up into a tree would be a good idea. I said sure, great idea. It would last a long time — something that most repellants currently don’t. Well, I just saw the article and I must say that I’m not so sure that it’s a great idea any more.

It seems that the repellant that they’re talking about is basically a combination of hot peppers and DMSO. The hot peppers have been around for a long time. The DMSO not so long — just a few decades really (though there is very small quantity of naturally occurring DMSO in fruits) but DMSO has some properties that concern me. When I was younger I was a competitive runner and I recall certain other runners using DMSO as a treatment for aches and pains. I also remember a run-down house along one of my regular runs selling the stuff via a cardboard sign on the porch. Looked kinda shady. I haven’t seen much DMSO around recently, maybe because it isn’t legal everywhere — at least as far as I can tell.

DMSO is a solvent which crosses membranes, such as skin, very easily. Apparently, if you use it anywhere on your body, it will make your breath garlicy. In terms of toxicity — it isn’t considered very toxic. However, it has the ability to dissolve things, such as poisons (the insecticide imidacloprid for example), and anything which it dissolves can then cross the skin barrier very rapidly right along with the DMSO.

So to me this is a little worrying. I don’t have much experience with DMSO, and I don’t have a problem with professional pesticide applicators who have the proper equipment applying DMSO, but I can’t help but wonder whether this stuff might be just a little too tempermental for the average homeowner to use. Apparently the EPA has it now. Here’s hoping that they’ll make the right decision, whatever that is.

Pesticides and Wildlife

If you follow this blog then you know that I write a lot about pesticides. They’re something that I enjoy reading about and studying. For whatever reason, I find them fascinating. That said, they can be some of the worst things for wildlife. But there are pesticides that are more “wildlife compatible” than others, so today I’m going to cover some of the worst pesticides that you can use in terms of wildlife, and some of the pesticides that might be more acceptable (though far from perfect).

First, here’s a brief rundown of pesticides that have been some of the worst wildlife offenders over the years. Fortunately most of these are gone.

1. DDT – long gone (though I know people who still have old bottles locked up in chemical cabinets here and there). Modern evidence points to it not being as bad for human health (cancer) as many made it out to be, but it was a mess in terms of environmental effects — it built up in the environment (it is stored in the body and is not rapidly excreted — in large part because it isn’t water soluble — so when a predatory bird ate a small mammal who had DDT on (or in) it, all of that DDT would stay in the bird — and the DDT from the next mammal it ate, and so on — this is called biomagnification) and resulted in predatory birds producing thin-shelled, barely viable eggs. Another problem with DDT was that it lingered for a long time — it doesn’t break down quickly. It had other problems too – but the biomagnification and persistence issues were the most obvious and, at least to me, the scariest.

2. Endrin – Relatively closely related to DDT, but a lot more toxic to a lot more animals and so a lot scarier. Once upon a time this stuff was used to all but sterilize fields. Toxic to everything that moves, and, like DDT, it built up in the environment. This stuff was (fortunately) never really used by homeowners.

3. Temik (aldicarb) – Nasty, nasty, nasty. EXTREMELY high acute toxicity, AND it’s water soluble. A pesticide which I have had to use in the past. Apply it to a tree (I was working with pecans when I used it) and that tree’s foliage would be free of any insects. And, amazingly, the stuff didn’t translocate to fruits and veggies – if it weren’t so darn toxic to things besides insects it would have been a great insecticide – some people still consider it a great insecticide. This stuff was known for its misuse. Apply it near a weed which deer eat and that weed would absorb the pesticide and poof! No more deer. Agonizing death too. Wolves and coyotes could be poisoned with just a little bit of tainted deer meat. This stuff wasn’t supposed to be used by homeowners, but, again, it is known as much for its misuse as its use.

Fortunately most of those over-the-top killers are gone or on their way out. Still, in your garden you do have the opportunity to use some poisons which it would be best for you to avoid if you’re interested in saving/protecting wildlife. These poisons are called “broad-spectrum” poisons and they are preferred by many because they kill so many different types of pests. Unfortunately being able to kill many kinds of pests usually also means that they’re able to kill many types of good creatures. Many pesticticides such as sevin (carbaryl), pyrethrin, orthene (acephate), and sulfur are broad spectrum poisons that you should avoid, but here are some that, if you want to conserve wildlife, you should be especially wary of.

1. Permethrin – This is probably the most used broad spectrum insecticide used around gardens today. It will kill just about any insect which it touches and it lasts for about 10 days. It is certainly effective, but it shouldn’t be used by anyone who wants to encourage insects or the birds who eat insects in their gardens.

2. Metaldehyde – This is a very effective slug poison. It is both attractive and deadly to dogs and cats, and is thought to affect birds and small mammals as well though there aren’t as many documented cases of wildlife poisoning as there are of domesticated pets being poisoned.

3. Copper sulfate (Bordeaux mix) – This is an organic fungicide that is often overapplied because it is considered safe. It can limit the plants which grow in an area, and it is extremely toxic to aquatics – keep it away from water. Finally – copper doesn’t break down – as you use it over the years it will build up in your soil – so try to stay away from it.

And finally, here are some which, if they are used properly, are less likely to affect wildlife.

1. Kaolin clay – it’s not popular, but it’s out there if you look for it. This is a type of clay which it sprayed onto plants to protect them from insects. It tends to work pretty well (it’s not perfect), but it has minimal effect on wildlife.

2. Insecticidal soap – It will kill some insects that you don’t want to kill, but it’s a heck of a lot better than permethrin. It is unlikely to hurt mammals or birds.

3. Roundup – The controversial part of me wrote this. Roundup has been implicated as doing all kinds of things to aquatic organisms, but, if it is only sprayed on the leaves of the plant you want to kill, it is not going to cause any significant environmental damage (besides removing a plant that wildlife may want for food).