The End (hopefully) of Molasses Malarkey

I’ve been discussing the purported insecticidal properties of molasses in my last couple of posts. I’m hoping this will be the final nail in the coffin (or stopper in the bottle):

Here’s the end of the original blog piece linked above:

“Microbial bloom and Fire Ants
“These two things seem unrelated. Microbes and specifically bacteria consume simple sugars (which is why your momma made you brush your teeth). When soil born microbes are exposed to simple sugars, their numbers can double in just 30 minutes. As microbes go through their life cycle, they add organic matter and micro nutrients to the soil, improving the soil and making nutrients more available to your plants. Regularly applying molasses to your soil and plants greatly improves the quality of the soil over time. Soils with high microbial activity are easier to dig in and stay moist longer.”

I’m actually going to leave this paragraph alone, since it’s relatively accurate (except for the sentence about applying molasses to your plants, which I dealt with in my first post). Let’s move on:

“So, about the Fire Ants…since it seems that the big universities can’t make money studying the effects of molasses on Fire Ants…they don’t do any research on the subject. But, it has been proven that molasses makes Fire Ants pack up their mound and migrate to your neighbor’s yard. It may be that the bloom of microbes, irritates the little stinkers. It could be that they are running from a specific microbe. It could be that they just hate sugar (they eat mostly protein which is why you can turn a greasy over baked pan upside down over a Fire Ant mound and they will clean it for you). What ever the reason, applying molasses to your yard makes them leave.”

This entire paragraph is nonsense, beginning with equating grease with protein (it’s a fat) and ending with the supposed lack of research on fire ants. There’s a LOT of research on fire ants; pest studies are very well funded. Out of the 1500+ articles I pulled up on fire ants in the Agricola database, only one includes molasses. And that’s in a 1986 study comparing different kinds of baits (“Comparison of baits for monitoring foraging activity of the red imported fire ant (Hymenoptera: Formicidae)”), where molasses was found to be more attractive to fire ants than peanut oil. How this translates to “molasses makes Fire Ants pack up their mound and migrate to your neighbor’s yard” I’m not quite sure.

“If you’re crunched for time and money, molasses is the answer to a lot of your gardening problems. The benefits are undeniable, your yard will smell great and you get to feel good about letting your kids and pets play in the yard. Whether you choose dry molasses (applied to soy chaff) or the liquid (which is cheaper to use), molasses is the single best thing you can do for your soil and plants.”

The typical snake-oil pitch! (For a completely unrelated but accurate and amusing example of an old-time snake-oil pitch, check this link. You’ll see the similarities).

“It was brought to my attention that I forgot to add this info. (It is hard to remember everything when you are trying to rule the world!) During moquito weather mix:

  • 3 tbsp molasses
  • 1 tbsp Liquid Garlic (a deterent and has some fungicidal properties)
  • 1 tbsp liquid organic fertilizer of your choice (seaweed, fish emulsion, etc) into 1 gallon of water

Spray with abandon, every week if necessary but it may last up to 2 weeks if we don’t get much rain. This also works like a charm on lace bugs on azaleas and lantana.”

Spray with abandon???? This has to be one of the most reckless pieces of advice I’ve ever read. Whether it’s a fertilizer or (more importantly) a pesticide, it should *never* be applied lavishly. (Though this is such a dilute solution that it probably isn’t much different than water.)

This topic has made me crave the molasses popcorn balls my grandmother used to make. Anyone have a recipe for those?

The Return of Molasses Malarkey

Last time I posted I began discussing this link about horticultural molasses. Let’s continue with the dissection:

“When molasses is sprayed directly on plants, it is absorbed straight into the plant. Once absorbed, the sugar content of the plant goes up. If you need proof, go pour a Coke on a spot in your lawn, in a week you will see exactly what I mean. Simple sugars are how plants store energy for rainy days and winter hibernation. So, why is this important to you as a gardener? Aside from basically giving your plants a power boost, you are stopping bugs. “What?” you ask. Yes, it stops bugs. Insects are very simple creatures. They can only feed within a narrow window of sugar content. When the sugar content of plants is raised, insects can’t feed on them. They take one bite and move on.

“The second way molasses controls insects, is by being directly ingested by the insect. What most people don’t know is that only Sugar Ants and bees can process the simplest sugars. Insects have no way of expelling the gas that builds up from fermenting sugar and the vegetation in their gut (draw your own mental pictures please). Plus, they have exoskeletons and can’t get bloated. Their delicate internal organs are crushed from the inside out. All a bug needs to do, is walk through or try to feed on a molasses covered plant. Insects are constantly cleaning themselves. They will try to lick the molasses off their feet and swallow it. If they take a bite of a molasses coated plant, they will swallow it.”

Some specific observations and comments:

1) “If you need proof, go pour a Coke on a spot in your lawn, in a week you will see exactly what I mean.” I just don’t think I can do this comment justice, so I’ll leave it to your imagination as to what you might see and how it relates to a 1% molasses solution sprayed onto leaves.

2) “Simple sugars are how plants store energy for rainy days and winter hibernation.” Actually, no. Simple sugars are difficult to store as they contain a lot of water and they can be quite reactive. Plants transform simple sugars (monosaccharides and disaccharides) into polysaccharides for storage.

3) “Insects are very simple creatures. They can only feed within a narrow window of sugar content. When the sugar content of plants is raised, insects can’t feed on them. They take one bite and move on.” Obviously the author has never seen Men In Black.

Give me sugar…in water

4) “What most people don’t know is that only Sugar Ants and bees can process the simplest sugars.” Please explain this to the cockroach I once saw in a sugar bowl.

5) “Insects have no way of expelling the gas that builds up from fermenting sugar and the vegetation in their gut. Their delicate internal organs are crushed from the inside out.” Did you know that termites are significant producers of methane gas – a byproduct of fermentation? And they release it the old-fashioned way.

From NASA’s website on methane production

More next week!

Molasses malarkey

Yesterday I received this link from a Facebook friend who said “when I read this I thought of you.”  More likely she was thinking of (enjoying?) the mental agony I suffered as I waded through this morass of misinformation. (By the way – those of you who are educators of some sort – this would make a great “how many things are wrong?” question for your students.)

There’s SO much to discuss in this post that I think I’ll split it up into separate posts.  Here’s the first paragraph:

“Cheap, easy and does it all!

“Not your kitchen molasses! That has had the sulfur removed and you need it in there. Horticulture Molasses does things for your plants like nothing else can and it’s the cheapest gardening product per square foot…a gallon can cover a half-acre! Put it in a sprayer, turn some music on and start spraying every inch of your yard, no need to be careful. You simply can’t over do it. Molasses raises the sugar content of plants and kills insects,causes a massive bloom of microbes in the soil and drives out Fire Ants, what more do you need?”

I’d not heard of “horticulture molasses” before, but there are so many new products sneaking into garden centers that I’m not too surprised. Let’s look at some specifics here.

  1. “Kitchen molasses has had the sulfur removed.”  This isn’t quite accurate.  Molasses doesn’t contain sulfur naturally; sulfur dioxide is sometimes added as a preservative during the processing of sugar beets or sugar cane and ends up in molasses.
  2. “Put it in a sprayer…and start spraying every inch of your yard, no need to be careful. You simply can’t overdo it.”  This is some of the most irresponsible advice I’ve ever seen. If this is such a powerful insecticide (as you’ll see later in the post), then OF COURSE you can overdo it.
  3. “Molasses raises the sugar content of plants.”  This bold statement has no basis in reality. Exactly how it is supposed to get inside the plants?  Not through the protective cuticle.  Through the stomata?  Possibly.  But how much sugar could be taken up this way? There are 256 tablespoons in a gallon.  Three tablespoons means that molasses is about 1% of the total volume in a gallon of this mixture (you’ll have to look at the bottom of the linked post to see the recipe).  And since molasses is only about 50% sugar, then a gallon of mixture is about 0.5% sugar. We’re talking about homeopathic levels of sugar here.
  4. “Molasses…kills insects, causes a massive bloom of microbes in the soil and drives out Fire Ants.” The microbe information is more or less correct (maybe not “massive” given the concentration of molasses used).  Microbes love carbohydrates.  The insecticidal claims are nonsense.  And since the next paragraph of the original post addresses this in more detail, I’ll hold off my dissection until my next post.

Vinegar: A Garden Miracle!

I’ve been working with homemade garden remedies in one context or another for about 10 years now.  As someone who has spent days searching for odd cures to garden problems I consider myself qualified to say that, of all of the remedies I’ve seen, vinegar seems to be the product with the most (supposed) uses.  You can kill weeds with it, as well as plant diseases and insects.  You can also use it as a fertilizer or even to acidify your soil.  It’s amazing!  But which of these uses are real and which are just someone flapping their jaws?

Vinegar as an herbicide:  White vinegar which is about 5% acetic acid and does a nice job of burning the tops of plants, but not their roots – so a larger weed will live right through a spray even though it will look bad right after the spray.  You can buy 20% acetic acid.  It works faster, but it has essentially the same problem killing larger weeds that that 5% acetic acid does.  Besides efficacy issues there are safety issues also.  I’ve used 20% acetic acid and I think that this stuff is too dangerous for the average person.  A little in the eyes could cause permanent injury.  Just a little whiff of it is enough to make the nose start running (in other words it’s not good for mucous membranes).

Vinegar as a disease control:  What a great idea!  Spray something that kills plants onto your prized petunias to control disease!  OK, when you use vinegar as a plant disease control you do use a lower concentration which shouldn’t hurt the plant.  But vinegar has never proven to be particularly effective at controlling plant diseases.

Vinegar as a fertilizer: Nope, doesn’t work.  Acetic acid only contains carbon hydrogen and oxygen – stuff the plant can get from the air.  The other things that may be in vinegar could be good for a plant – but it seems an expensive method of applying an unknown amount of nutrition.

Vinegar as a soil acidifier:  This is one that I’ve seen a lot – and so I tried it.  In a nutshell, it just doesn’t work that well.  It takes a lot of vinegar and the pH change is brief at best.  Use something like sulfur instead.

So to summarize, despite a lot of recommendations, the only thing that vinegar has really proven to be good at is killing weeds – and then only if the weeds are young.

Off-label Use of a Chicken*

 

[Extremely] Preliminary research results from the University of Maryland indicate
chickens may be of interest in the fight against Halyomorpha halys, the brown
marmorated stink bug. 

There are good stink bugs and bad stink bugs. The brown marmorated stink bug is a bad one. A relatively new introduced pest, it is piercing, sucking, and generally ruining vegetable and fruit crops (as well as some ornamentals) across a good part of the U.S.  There are apparently few natural predators for this imported species and they reproduce like mad, thus the potential for this to become a very serious economic issue. USDA funding has appeared, and scientists are working against the clock on every angle of the problem.

Dr. Stanton Gill, Extension Specialist in IPM for Nurseries and Greenhouses at the UM Central Maryland Research and Education Center, is among them. He is not only a great entomologist, but a total hoot, just like several other bug people I know.  He’s doing plenty of conventional research as well as loads of critical Extension service spread out over several states. As an orchard and nursery owner, he also has a personal stake in the issue.

I had the pleasure of hearing about Dr. Gill’s latest work at a recent nursery association meeting. He related the severity of the problem as well as several stink bug-related research projects he’s involved with, but the one that really caught my attention was his work with chickens.

On a tip from a gardener/hen owner, Dr. Gill decided to explore further. In a nutshell: the stink bomb hidden in the thorax of Halyomopha species is a terrific defense mechanism against bird and reptile predators. But chickens seem to be immune (and unconcerned about their breath). Actually, not a big surprise – I’ve caught my hens eating some pretty amazing/disgusting things.  His preliminary study consisted of a few borrowed hens in a couple of nice little fresh-air pens, free to scratch about. A request to some battle-weary local gardeners yielded tupperware containers full of brown marmorated stink bugs. Through some feeding trials, he found… a hen’s capacity for stink bugs knows no bounds.

The hens had access to their regular feed, but gobbled up all the stink bugs offered. I can’t recall the exact quantity, but it was A LOT.

Stink – it’s what’s for dinner.
Action photo courtesy of Dr. Stanton Gill, University of Maryland
.

The hens would only go for the stink bugs if they were active.  Dr. G. put some in the freezer (stink bugs, that is), rendering them immobile, and the girls turned their beaks up. Once thawed and moving (!!!), they became dinner.

Finally, he worked with a food scientist to answer what should now be a burning question – did the eggs taste funny?  Blind taste tests found that participants preferred the eggs produced by the stink bug-eating hens versus controls. I believe further studies may be in the works, as well as some publications relating his findings.

* Ha, ha, I kid!!! This post is neither an endorsement nor recommendation of the research described within. There is no MSDS available. No REI. No PPE guidelines. No EPA approval. No acronyms at all, actually. You’re on your own.

A comment about home remedies from Catherine Daniels

In case you didn’t see yesterday’s comment that was added to Jeff Gillman’s January 6 post on home remedies, I’ve posted it here.  Dr. Catherine Daniels is WSU’s pesticide coordinator:

I’ve enjoyed reading the science-based information on your site. Keep up the good work. As regards home remedies, that is slippery slope, both legally and morally. Having a written definition of what you will or will not accept is helpful, especially if done in advance. Then you can be sure of being consistent and deliberate at least. There are both state and federal laws regarding pesticides, and state laws do vary. The most important thing is to know your state’s interpretation of those laws and to be mindful that with a blog you may be talking to people in state’s where laws are interpreted differently. I mention that for your legal protection. For example, in Washington State, if you talk to a user group (such as the public), and discuss the ways to use a material as a pesticide, it becomes a de facto pesticide recommendation. A legally-liable recommendation. When a researcher publishes information in a journal it’s not directed at a user audience so is not considered a recommendation by the author. If you take it to the public, at least here, it becomes a recommendation you made, unless you insert certain disclaimers. It’s always attractive to try and “help” the public find some easier, faster, cheaper solution to a pest problem. With pesticides and the public, you offer a better service directing them to a tested material which is registered and has a consistent concentration from batch to batch. Having personal safety and storage instructions is important…things that are missing in make-it-yourself squirt bottle solutions. Home remedies encourage people to think that the solution is “safe” (for people, not pests) because it’s made out of everyday ingredients. But as we know, the dose makes the poison. Nicotine is a nerve poison which you wouldn’t want a child to come into contact with accidentally because the squirt bottle wasn’t labelled or put in a safe place. I agree that our role is to educate, not police household cupboards or public pesticide use patterns. But by the same token, because we (educators)are trained to look at the big picture, there are good reasons to consider sticking to a label. Thanks for the opportunity to comment.

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.

Bounce – it’s not just a fabric softening sheet…

…it’s an Integrated Pest Management tool!

[Note added after-the-fact: this was a  tongue-in-cheek bit of  hyperbole – kind of like “it’s not just a Job, it’s an Adventure.” Did not mean to imply that it actually IS an IPM tool. Very badly worded. Hence the beating I took in the comments. Live and learn.]

Fungus gnats (Bradysia spp.) are a pain in the bottom for commercial greenhouse growers. The adults are more of a nuisance than anything else –it just looks bad when a customer picks up your 6” pot of pansies and a bunch of little black gnats take flight.  It’s the larvae that are problematic. Adult females lay the eggs in especially damp growing media, and the newly-hatched larvae feed on the roots. There’s both direct damage and also speculation of easier infection of root-borne pathogens, of which there are plenty. 

 
Fungus gnat larvae, just making a living…

Standard control measures include insecticide drenches, biological controls including a specific strain of Bt (Bacillus thuringiensis – sold as GnatrolTM), nematodes, etc.  One of the easiest control measures is the one I teach my students: to not over-water, i.e. “grow dry”. But that can be difficult in a big greenhouse range with many different-sized containers, all which drain/dry out at different rates. Propagation houses also have high humidity levels and have to stay moist for rooting/germination purposes and are thus favored by fungus gnats.

Entomologist Dr. Raymond Cloyd of Kansas State University and his group were intrigued by Master Gardener anecdotes of dryer sheets repelling mosquitoes, though no research had been done. Could your common Bounce sheet also repel other pests? And, to take it a step further, what, exactly, repels them?  The answers are “yes” and “lots of volatile compounds.”

Their study was published last month in the journal HortScience. Honestly, I’ve never seen descriptors like “controls static cling” and “gives clothes a fresh scent” in a Horticulture journal. Hee! Plus the researchers made it clear this experiment specifically used Bounce Original Outdoor FreshTM. Still kind of humorous, but really good science and the part that’s usually overlooked in the translation to a News Story. Do NOT extrapolate results to include Bounce Spring Fresh, Fresh Linen, and certainly not Downy or Snuggle brands. 

The study had a simple design, releasing lab gnats (ha!) into a  many-chambered container and observing to which chamber the gnats gravitated to (or away from).  There were five different variations on this theme, including an alluringly soggy media sample; when the sample of fabric softener sheet was introduced, they stayed away in droves. All five experiments showed a fairly drastic aversion to the sheet. To determine what was fending off the gnats, they did a steam extraction on sheet samples and ran the condensate through a gas chromatograph – mass spectrometer to measure the volatiles.



Figure from Bounce® Fabric Softener Dryer Sheets Repel Fungus Gnat, Bradysia sp. nr. coprophila (Diptera: Sciaridae), Adults. Raymond A. Cloyd, Karen A. Marley, Richard A. Larson, and Bari Arieli, HortScience Dec 1 2010: 1830–1833

Well, there you have it. Linalool is a monoterpene alcohol found in lavender, basil, and coriander, and is known to be toxic to mites and insects.  Citronello is another monoterpene and lends lemony-freshness to lemon balm, pennyroyal, and rose geranium and has short-term “repellent activity against mosquitoes.”  Benzyl acetate, though not specifically mentioned in the results, is another natural fragrance compound, found in jasmine – and is also an industrial-strength solvent. One man’s solvent is another man’s perfume. Or fabric softener. I bet their lab smelled GREAT, by the way.

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6

Almost But Not Quite

Today I was reading an interesting gardening website with a wide variety of advice, some good and some not so good.  As I analyzed the website in my mind to figure out why some stuff was good and some stuff was bad it occurred to me that the problem was that a lot of the stuff that the author was recommending was based on testimonials.  And then it occurred to me that many of you out there might not know what a testimonial is and why recommendations based on testimonials shouldn’t be recommended — and then viola! I had a blog post.

A testimonial is testimony presented by one person about their experiences with something.  It’s like when a friend tells you that dryer lint controls slugs in a flowerbed. Don’t laugh, this is a real suggestion on one website!  This person decided that it was appropriate to put dryer lint around their garden, and when they did, slug damage appeared to be reduced.  Good for them.  But is it good for you?  The answer is maybe.

The problem is that this person is missing the two things that we need when assessing whether a particular thing works.  First, we need a a control, and second, we need replication.  Let’s use the dryer lint example.
We have no idea whether, if we hadn’t put out the dryer lint, the slug population might not have dwindled anyway.  To find out whether it might have we need to treat only a portion of our garden with dryer lint and then see if the treated portion has more or less damage than the untreated portion after a few weeks.  The untreated part of the garden is called a control and it is necessary for a good experiment.  But it isn’t the only thing necessary for a good experiment, so is replication.

It is possible that the part of the garden which was treated with the lint had less slug damage than the control portion of the garden for some reason besides the lint — for example, perhaps the area where the lint was applied happened to be further from the sprinker than the other section — and slugs like it moist.   So to combat possible problems like this you need to conduct your experiment more than once.  In other words, you need to replicate your trials.  This might be done by doing this experiment over multiple years, by having other people in your gardening club try it too, or by dividing up sections in your garden into six or so equally sized sections so that three randomly selected sections get treated with lint and three don’t.  Or, best of all, do all of these things — multiple years, multiple gardens, and multiple plots within a garden!  If we did more testing like that I have a funny feeling that we’d have fewer crappy products for sale.

Testimonials are interesting, but don’t get fooled into thinking that they prove anything.  They don’t.  You need control and replication to demonstate that something really works.

Want an organic source of nitrogen that isn’t shipped from halfway across the world? Urine luck

There are lots of organic fertilizers out there:  Fish emulsions, corn gluten meal, guano.  Many of these fertilizers (all that I listed above with the exception of the guano) are by-products of some other industry.  Still, they need to be shipped from somewhere to somewhere to get to our garden and so they cost energy — and of course they cost us money.  But there is a high nitrogen fertilizer that you can use which doesn’t come from a long way away, and that’s pee.  Holly  mentioned using pee to help compost piles of stray a few months ago (you can find the news story on the right side of this blog), and I, for one, think it’s a great idea.  But really, pee can be used as a fertilizer without the compost.

Yesterday I was working on a project and decided to goof off a little by figuring out how much nitrogen was actually in urine.  Here’s the conclusion — Urine contains about 4,000 pats per million nitrogen.  In terms of what plants can handle, that’s a lot (which is why dogs produce “dog spots” when they pee on a small area of ground — too much nitrogen in a small area).  400 parts per million nitrogen, applied once a week in irrigation water, is what you might apply to encourage the growth of greenhouse plants.  Urine, by the way, is also relatively sterile (unless you’re dealing with a bladder infection) and so using urine is relatively safe as long as it’s used quickly.  It also conserves water because you don’t need to flush.  So, the way I figure it, you could mix 1 part urine with 9 parts water and have a really good once a week (or two weeks) fertilizer application for your flowers (I don’t know if I could bring myself to fertilize cabbage, broccoli, or tomatoes with it…).  You’d be saving yourself the cost of fertilizer, saving the environmental cost of shipping the fertilizer you might otherwise purchase, saving water, and you’d have something unique to tell your gardening friends about.  Win – win situation as far as I’m concerned.