Avoid this sprayer!

Assumptions are pretty rotten things all around. When I suggested to several students and clients that they use ZeroTol to control bacteria or fungus, I ASSUMED they would do it the way I did it: Fluid ounce measures filched from the kitchen years ago, long rubber gloves that went nearly to my armpits, a handy backpack pump sprayer, and muttering poetry I’d half forgotten under my breath while waving the sprayer wand around like an incantation. Skip any of those performances and I could never guarantee success.

About the product ZeroTol, though, I do admit being completely oblivious that there was a sprayer available that attaches to your hose and does a thoroughly dreadful job. In truth the ZeroTol sprayer is one of the only ways to avoid buying 2 ½ gallons of the stuff, and naturally several of those I was advising bought the sprayer. But the sprayer can offer such a bad and inaccurate concentration that one person reported burning moss with it (which should never happen with a proper mix). ZeroTol is seriously caustic at high concentrations. One friend left a jug of it uncapped and found the remains of a mouse dissolved in it. Many attachable sprayers need a certain hose water pressure to get the mix right, which ought to make you nervous. There are a number of variables that you have no control over and getting a good mix is simply a guess and a hope. Naturally I was appalled that I had unwittingly led some people to use this attachment.

Although this example is of just one product, it should be a cautionary tale for any one-time-use hose sprayer:

  • When we use chemicals, get serious. And cheap hose-adapted sprayers are not for the serious.

Better to skip this hose sprayer

Get set up to use chemicals right. You want to be in control of all variables. Use a one or two-gallon pump sprayer for a small collection, or a backpack pump sprayer for a modest sized collection. Rather than stealing the fluid ounce measures and teaspoon measures from your kitchen, buy a second set. Add your measured chemical. Drag up your hose and add water carefully to the line on your pump sprayer for the gallons you are calculating for. Mix thoroughly and apply under high pressure, don’t let it spit around after a few swift pumps. You want very fine mist, so pump it well. You can forget the poetry.


Backpack sprayer, a better option

Main point:

  • Avoid hose adapter sprayers for biological control chemicals. Bad idea. The mix can be deeply inaccurate.

(A note about spraying: There are two broad categories of chemicals that we use for plants, contact and systemic. If you use a contact chemical be sure that you’ve completely coated the entire foliage surface of the tree. That means you’ll be poking your sprayer nozzle into holes in the foliage pads, spraying up underneath the pads, and making everything drip. If you leave a few leaves or needles unwetted, you’re just wasting your time. A systemic is very different in that it is translocated within the plant and usually has longer term protection. It can be brought into the plant by its foliage, but it can also be brought in by the roots. So that means spraying the whole tree, and possibly a drench with a watering can. So your tools might be different in applying different chemicals. Read your labels and do what they say.)

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  1. Thanks for the heads up!

  2. Howard says:

    Michael, you’re so right. I remember advising a patient with abdominal pain from heartburn to use Mylanta every two hours. When I next saw her, she said she was no better. I asked how she was using it and she said “just as you told me – I rub it onto my belly every 2 hours.
    It’s the fine print that’s critical!

  3. Hi Michael.
    Just a quick question. I have a trident that has been in the ground for some years now. In the trunk there are 3 trees that I want to layer out. Can I layer them out at the same time, or should I just do one a year starting at the bottom.
    Thank you for your time.
    Qualicum Brian

    • crataegus says:

      Do them separately— unless you have a lot of branches, and radial positioning of them all, in between layering areas. Reason: You need the food coming down the tree to push out your roots. So, in general, they should be done one at a time.

      • Thank you Michael
        I have layered the top and it is in the greenhouse . We are experienceing a very mild year here on the island. Trees are well on there way.
        See you in Victoria in the fall. Hope to to get into your workshop . Don’t know what you are doing yet, but I’m sure it will be fun. Is Matt at the moment in town and will he be coming up with you. Like to see him.
        Thanks again
        Qualicum Brian

  4. Alex says:

    Hey Michael,

    I’m curious, what do you generally use for fungicide/pesticide?



  5. anijhuis says:

    ZeroTol — oh – 27% hydrogen peroxide the rest is Hydrogen Dioxide and
    Peroxyacetic Acid. Makes a really good herbicide.
    I use hydrogen peroxide to disinfect my tools – kills bacteria. Will also kill the good bacteria in your bonsai soil which is needed to break down fertilizers.

    It is a good product for professionals to use in greenhouses and nurseries sorry Michael but should be avoided by the public.

    Alternative is baking soda to kill algae but watch the pH.

    When using a systemic remember your botany; phloem and xylem.

    A soil drench with a systemic will carry the active ingredient through the xylem up the plant to the leaves, stems and roots.

    Applying a systemic on the leaves the active ingredient is transported down the plant in the phloem – it only goes down and not up. If you spray just the lower branches the ative ingredient does not travel up to the rest of the plant.

    Fungi is host specific and there are many thousands of fungi; wettable copper, bordeaux mixture, Daconil and sulpher all work on specific fungi.

    Mycorrhizal fungi is host specific don’t fall for purchasing these products for your plants chances are they wrong kind – odds are the same as the lottery.

    3 rules for using pesticides:

    1) Read the label

    2) Read the label
    and finally

    3) Read the label!!!!

    Anton – IPM – integrated pesticide management applicator

  6. Al Keller says:

    I have been using “Oxidate” for a number of years but I was advised to use “zerotol” instead. The reasoning, or so I am led to believe, that it is basically the same formular as “Oxidate” and is quite a bit less in price. Your input on that ?? Thank you, Al

    • crataegus says:

      I am not familiar with oxidate.
      Zerotol has its uses, although I use it only as a second or third rung on my ladder of controls.

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