Pesticide Control: Commentary on Bayer

As those of you who’ve been following this blog for a while (my condolences) might know, I tend to lean heavily on aesthetics, philosophy, and flights of fancy. Well, just to balance things out a bit, I thought we’d chat briefly about the raw side of bonsai: Pest control.

Mostly I’d like to talk about Bayer today. For those of you unfamiliar with Bayer, they make a line of products that work against many pests. They are effective, and their products are easily found in many stores. Those with 50 trees or less might well find that careful use of Bayer can take care of many pest problems, including Adelgids, Aphids, Borers, Caterpillars, Leafminers, and Scale. Curiously, although there is some evidence it can affect the life cycle of Spider Mites, it is not very effective against them and may in fact harm the predators of mites more than the mites themselves, causing an inverse response that can cause outbreaks of the mites.

The insecticide active ingredients in Bayer are primarily imidacloprid, and secondarily, clothianidin. They are insect-specific poisons that have much less toxicity and danger to mammals, fish, and amphibians (although there is some). These chemicals are of similar chemical structure as nicotine which has been used as an insecticide for a very long time. At first glance, this product seems to have great utility.

But, please note: Imidacloprid is not a benign insecticide. Its use must be limited to non-bee attracting plants. Imidacloprid is thought to be a major contributing factor in honeybee colony collapse disorder. Consider a different pest control with your flowering bonsai.

With that cautionary tale regarding bees, you may find limited use of Bayer to be helpful. Unfortunately, Bayer makes several products which are so similar that they have confused me several times in the past. Rather than run through all the products, I’ll just post a picture here of the label of the one I’ve found most useful. The reasons that this is the one I prefer is because it is 1. listed for use with containerized plants (which many of the others aren’t), 2. it’s a long term systemic as opposed to a short term systemic. That it has a little bit of fertilizer in it does not bother me too much, especially because one application will last many months. (I prefer pinpoint control with fertilizing each individual plant, and if it had more fertilizer in it I’d be shy of using this product.)

The most useful Bayer product for bonsai

The most useful Bayer product for bonsai…but please read entire post for cautions!

One teaspoon per gallon takes care of a lot of common pests. Drench the rootball with the dilution. With deciduous trees the effect of the systemic is perceptible within a day or two in warm sunny weather, which is seen in the fast translocation from the roots to where things are nibbling or sucking on the foliage above. It will work for aphids and adelgids on a pine or juniper as well, it just takes about 5 days for the slower translocation of those trees before you see dead insects. Try spraying the tree with the product at the same time as drenching the soil.

If you’ve a small bonsai collection definitely consider applying any pesticide only when you see a problem. The fewer poisons, especially long-term poisons, we have sitting around in soil and in the tissues of plants the less problems we’ll have with other beneficial insect life. Although very fugitive in sunlight, these chemicals can last a long time when underground or in plants. Prophylactic spraying should be reserved for larger operations, perhaps using different chemicals, and again not around flowers that might attract bees.

I felt commentary on Bayer to be important not because I’m specifically endorsing it, but because it’s so readily available and so many of us are using it that awareness of its limitations and dangers would be helpful. Anyone who wishes to comment on their experiences are certainly welcome to do so (especially chemists and entomologists!)

(COMING SOON: Post of the first Portland Bonsai Village tour!)

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  1. Peter Keane says:

    I’ve been using Bayer for years on my bonsai. I “guestimate” my concentration when mixed with water. As my soil is quite free-draining. I’m not worried about killing trees from an overdose.

  2. Elliott Farkas says:

    Hi. I use the 3 in 1 bayer product alot in my yard. My guy at the nursery supply say’s the amount of fertilizer in it is extremely low.
    The label says use aprox every 6 weeks, but I noticed it stops working after about 3 weeks. I suspect it’s because of our fast draining soil and daily summer watering washes it out faster, so I use it every 4 weeks.
    Recently, some of us im So Cal. Have been noticing sudden die off of branches of grafted junipers with Itoigawa even on trees with the bayer.
    We found out that we had twig borers that liked the Itoigawa and were not bothered by the Bayer.
    We used a product called Bifen ( google it, it’s cheap and available everywhere online).
    We had immediate results and no side affects on several different species and no problem spraying it in hot weather.

  3. Janet Roth says:

    I use the Bayer Insect, Disease, and Mite Control – I buy it in a spray bottle ready to use. This works very well for my very small collection. For all the reasons you state I don’t use it as a prophylactic. FWIW – the container has a big label on it stressing that it is effective against mites, and includes spider mites among the specific pests it treats. I don’t know – yet – if it has been effective against disease – but I’m currently in the process finding out.

  4. Ian Weyenberg says:

    Are there no organic or less questionable long term effect alternatives to something made by the company that invented heroin? Bayer, philosophically speaking, is evil, on the level with Walmart. IMO. I trust their word about as far as I can throw my car.

    Thanks, Ian

    • crataegus says:

      There are plenty of organic and softer insecticides, starting with soaps and oils. There are millions of web pages that offer alternatives to bio-designed chemicals, and they’re definitely worth a look!

  5. Bryan Gardner says:

    It’s used by many reef aquarists as well to dip newely aquired corals in before adding to the reef tanks to keed unwanted pests from entering. Extremely effective but yet gentle product.

  6. Bruce Winter says:

    I sure appreciate the low toxicity of this stuff but I hadn’t thought of using it as a root drench. Maybe I could eliminate Marathon (same chemical, and expensive).
    Love the tour!

  7. John Cotoggio says:

    Hi Mike,
    Some how when ordering, and probably not paying closer attention, I wound up buying the granular version of the Bayer. Will this work just as good ?

    • Elliott Farkas says:

      I prefer the granular version. It’s the only one I use. No mixing! I toss it around my yard like I’m feeding chickens, LOL!
      The truth is, I either just put the amount on the directions sprinkled on the soil surface or I put it in empty tea bags I buy at the local asian supernmarket. ( i’m sure available online ).
      What I have been wondering since this post came out, what is the salt content in granular or liquid for that matter? We generaly avoid inorganic fertilizers here in So. Cal, because of our heat, and inorganics are made out of salts that will burn the leaves on hot days.
      I do see some leaf burn, but when average summer temps are 95 f with low humidity, you almost can’t avoid that.

      • John Cotoggio says:

        Hi Elliot,
        Thanks for the reply ! I saw you mentioned a product called Bifen. I looked it up but there are several. Which one were you using if you don’t mind me asking ?

      • Elliott farkas says:

        It was just plain Bifen. I know there are several. Just read up on each. I think the difference is concentration or dry versus wet product. I was at Boon’s last weekend and turned him onto it also.
        So far, we have not noticed any bad reactions from any trees, but always spray a couple of leaves first, wait a couple of days, then go ahead if the test area is good.

  8. Kevin Faris says:

    Hi Michael, when you say it works dor aphids. Do you mean root aphids? If so I have done a Bayer soak on 3 Scott’s pines that have been infested with ants and thus leading to root aphids. Just wondering in your experience if you have seen it work for root aphids?


    • crataegus says:

      It can work but you have to keep up on it, as a single application doesn’t seem to do it. Also you might try a stronger systemic if you have it.

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