I love the Smell of Pesticides In the Morning!

I love the Smell of Pesticides In the Morning!

Aphids attacking new growth on a Japanese Maple

Well it’s that time of year again!  Spring is in full swing here in Nagoya and deciduous trees are producing nice juicy new growth that bugs love to feast on.  As the breeze comes and goes, there are fungus spores flying all around us as well and they too can cause problems with out trees.  Today at the nursery we decided to bring out the the big guns and spray all the trees to control some of the Spring bugs and fungus that are out and about.  In this post I will talk about what we use when spraying and how we spray.  Perhaps at home you are currently having bug or fungus problems and not sure what to do.  Hopefully this post will give you some insight on how to control the pest or fungus you may have on your trees.

Recognizing the Bug Problem

Here in Nagoya, it can get very hot/humid and there a plenty of bugs that love those conditions.  For others in the world that live in drier environments, they too have their own set of bug problems as well but it seems to be not as aggressive.  First thing to do when we think we have a pest problem is to find out what kind of bug it is.  Certain types of pesticides will only work on specific insects and may not solve our problems and could potentially increasing the problem.

During this time of year, one of the main culprits are aphids.  Aphids are currently feeding on the new growth on deciduous trees.  What I’ve noticed this year is that aphids have started to feed on Japanese Maple first.  As their population increased, they then started showing up on Trident maples and other trees.  Japanese quince tends seem to attract a lot of aphids as well.  During the Spring as I was pinching many of the maples, I started noticing more and more aphids everyday and that sent up the red flag that it’s time to spray.

Back home in San Jose, California, I didn’t have any Japanese maples but I always had a problem with aphids attacking my boxwoods and only my boxwoods.  So depending on the area, aphids may have different feeding habits, so it’s important for all of us to recognize the pattern in our own backyards and address it accordingly.

The other main pest we have here are thrips.  These bugs tend to attack the Trident Maples first and like to hide on the underside of the leaves.  They keep sucking on the leaves and cause them not t0 develop properly and cause the leaves to have a dry brittle and curled look to them.  As the temp gets higher, thrips will be much more prevalent.

If you would like more basic information on aphids and thrips, you can read about them on wikipedia.com by clicking these two links: Aphids, Thrips


Fungus is another problem that can potentially arise at the nursery.  The difficult thing about fungus is that we cannot see them.  Only when we start to see the damage on trees do we realize we have a fungus problem.  For the most part, we do a lot of preventative spraying for potential fungus problems.  There are certain trees that we know are very susceptible to fungus problems such as Flowering trees so we take extra care to really soak the tree with fungicide.  Other things we do to stop the development of fungus is to not overhead water leafy trees.  It can be very effective to prevent fungus problems just by keeping the moisture level down on the areas that are most affected by fungus, i.e. the leaves.

When We Spray and How Often

A cool and cloudy Spring day

Here at the nursery, we spray the trees about once per month.  High temperatures and humidity levels forces us to spray more often because the insects seem to be much more aggressive in their feeding.  The best time to spray is when the temperature is cool early in the morning or late in the afternoon.  There’s been times during the Summer where Mr. Tanaka and I were up at 5am to spray because that was the coolest time of the day!

The reason why we spray during the cool times of the day is that the foliage of the tree is not as active at low temps.  If we sprayed the trees at the hottest part of the day we can cause the foliage to burn because it’s being coated with chemicals at it’s most active time.  If we sprayed in the middle of a hot day the foliage will burn, drop off and weaken the tree.

Spraying can be serious business here in Japan because if the trees are not sprayed regularly, insects will start to feed on the tree.  The insects here are aggressive enough that they can turn a large bonsai tree yellow within a few weeks and weaken the tree enough where sections or branches can die off.

This month we’re using a mix of Malathion (pesticide) and Daconil (fungicide).  Both products are readily available at most garden centers.

What Are We to Do?

So depending on your climate and situation, your regiment in pest control will vary from us.  Back in San Jose, California, I hardly did any spraying at all because the pest problem was just not as severe.  Carefully look through your collection of trees and gauge how much pest control you need and set up a schedule for pest management.  I would be a shame loosing trees or branches because we didn’t catch the insect/fungus problem in time.

Let’s Get to the Spraying!

First thing we did was mix the Malathion and Daconil with water.  Be go through about two of these containers for the nursery.  We followed the instructions on the bottle of both chemicals.  It’s then important to really mix the chemicals with the water.  I’ve heard plenty of stories where apprentices will forget to mix pesticide throughly and end up spraying 100 percent pesticide on trees and severaly burning them.

This is the setup that we use.  We have a gas powered pressure washer that feeds the pesticide to a high pressure line and sprayer.

Before we start to spray the trees, we watered every tree at the soil level only.  This will help dilute the chemicals further down when it hits the soil and not cause any potential problems with the roots.

Here’s Mr. Tanaka in action.  As you can see, the pesticide/fungicide is coming out at a very high pressure.  We use this pressure to completely cover the trees top to bottom, inside and out.

As Mr. Tanaka was spraying, I was assisting him with the line.  Though I had a mask on, I wanted to stay as far away from the mist as possible!

Here’s a shot of a Five Needle Pine dripping with Pesticides/Fungicides

Here’s a shot of a Trident maple completely covered in the spray.  Most bugs like to hide on the underside of the leaves so its important to get the pesticide/fungicide there as well.  That’s why the high pressure sprayer works so well because it moves the tree foliage around and allows the pesticide/fungicide to cover everything.


Afterwards I rinsed out the equipment and put them all away.  Next was to clean myself up so I stripped off my chemical covered clothes and jumped in the show to clean off any chemicals that may have landed on my skin.  As for the trees, we leave them alone and allow the pesticide and fungicide to do their  job.  Once I was cleaned up, Mr. Tanaka said to my surprise, “take a break for the rest of the day.”  At that point, I quickly went to my room and started writing this post.  ;oD

For those that want to search older post, I have refined the search categories (on the right column) so it’s easier to find a specific post.

Thanks for reading.

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41 thoughts on “I love the Smell of Pesticides In the Morning!

  1. Ed Curlee says:

    Thank God for bugs, fungus and weeds. gives me something to do with my “spare” time.

  2. Neil says:

    Thanks for a good post. I am curious to know what the pesticide is that you use for controlling mites? Also, what other fungicide is rotated? One of the biggest fungal issues I have is the quick transition between wet/cool spring and the heat of summer. Succulent growth is always likely to be infected if preventive measures are not taken.
    Best regards,

  3. Zack Clayton says:

    To amplify what Cheryl said, If you have 3M products there, they make a 1/2 and 1/4 face unit that will take cartridges specifically designed for pesticide use. All cartridges have a point of breakthrough where the cartridge becomes saturated and is no longer functional. They are inexpensive enough that for the use you guys are giving them, use a fresh cartridge each time you spray.

    One other note, I learned from a local professional that a tablespoon of Pine-Sol in a gallon of water will get rid of many bugs. I am not sure if its the soap action or the turpenes in the mix that does this. As it is NOT a label use, the mixture is applied as a leaf wash to keep the leaves looking pretty. And, oh BTW, it also kills pests. I use it as a first step and often don’t have to go to a second. It does not affect mites however.

    • Peter Tea says:

      Hi Zack, I combined your comments into one.

      The next time I go to the home center, I plan on buying a face mask for pesticides and some goggles. I appreciate all the concerns you and the other readers have. It seems that the exposure is relatively low in comparison to farmers and major nursery operations, but of course, it’s always better to be safer then sorry.

      I talked to Mr. Tanaka about it and he says that the farmers are the ones that are really exposed to that stuff. He tells me that the typical cabbage growers spray the veggies almost 20 times with pesticides during their three – four month growing season. Of course, they have to deal with worms.

      I think this year, I’m going to try spot spraying trees with insectal soap to control some of the pest and perhaps reduce the amount of spraying we have to do. The pest in Japan are very aggressive and I can see why bonsai pros here have opted for chemicals.

      Thanks for the comments Zack. Take care!

  4. […] I recommend you read Peter Tea’s account of Aichi-en’s battle against the bugs, “I love the smell of pesticides in the morning.” Share this:ShareFacebookTwitterDiggStumbleUponRedditEmailPrintLike this:LikeBe the first to […]

  5. Randi Sharp says:


    For years and years and years I have been spraying first with a pesticide and then wait a week and spray the fungicide. What a great practice to combine them. No matter the post, I always have a lesson learned! Keep up the great work!

    • Peter Tea says:

      Hi Randi,

      When I saw them combine everything for the first time, I was like, “Duh, why didn’t I think of that!” LOL

      Thanks for the kind words Randi. Take care

  6. Marcelo Campos says:

    Peter, hi. I absolutely do agree with Cheryl comments. Malathion is very toxic (the little dog around is in danger, too). Depending on how often you guys are spraying it, you may need some assistence to check levels of exposure (blood tests) searching for early sigs of intoxication. Hope you and the plants will be ok.
    regards from Brazil

  7. yenling29 says:

    Great Post! Do you know what Mr Tanaka thinks about Systemic insecticides?

    • Peter Tea says:

      Hi Jeremiah,
      Mr. Tanaka does use Systemic every 2 months or so. From his experience, it doesn’t work as well as the spray. Also, he says he notices that some of the interior weaker branches tend to die off when systemics are used. His feelings are that having chemicals circulating the tree’s system is not ideal and thought it won’t kill the tree, it does weaken the tree.

      Thanks for the comment. Take care!

  8. Nathan says:

    Very timely post for me. I’ve applied both of these however, thought that the label indicates different application strengths per gallon based on species. Meaning pines might get one strength and maples another. Do application rates vary among species? Would a hand help pump sprayer work just as well? LOVE the post!

    • Peter Tea says:

      Hi Nathan,

      You are very correct that different trees takes different amounts. Normally, we go with the lowest concentration since we’re spraying everything and that seems to work pretty good. If we were to spot spray a certain tree, we would probably up the dosage.

      Hand help pumps will work just fine. That’s probably what 99 percent of the bonsai people in the world uses to administer the pesticides. My only suggestion is that you need to get the spray deep inside the tree and take some time to thoroughly spray the underside of leaves. With the pressure washer, the spray is so strong, the pesticides gets everything covered, whereas a hand pump isn’t as strong and might only cover the exterior of the tree. Most bugs are usually hiding on the interior or underside of foliage.

      Thanks Nathan and take care!

  9. Rui Marques says:

    Do you have any neighbor complaints?

  10. somchee says:

    Hi Peter,
    As always your blog is terrific. I worry about he dog’s water. Malathion is great but really toxic even years later. It kills the liver and kidneys very slowly.
    For the aphids on a very small scale I learned to collect the bugs, add water…run them through a blender…strain it though a stocking and spray. It kills them really well but harmless to people, dogs, good bugs, birds etc. The theory is some of them are carrying diseases that will kill off the rest and it always worked for me, Not as fast but very safe and effective. A teaspoon/tablespoon of aphids to a quart or two of water…roughly. Sort of giving them all a bad flu.
    I use more chemicals myself now because it’s easier and my allergies are not so bad. Also fewer aphid problems. For fungus I used sulfur….messy not so good and finely gave up when I became allergic to that. I now use the Daconil as well.
    I look forward to your postings…please keep it up.

    • Peter Tea says:

      Thanks for the comments Somchee,

      The dogs weren’t exposed and the water dishes and their areas are always hosed off with water after the spraying.

      Very interesting technique you have for aphid control. Instead of Chemical warfare, you’re going with biological warfare instead. LOL I would like to try this out in the future and see what kind of results I get. Thanks for sharing it!

      Take care

  11. Lucky says:

    Your article was very timely as I have only recently started to spray my Satsuki
    bonsai. The chemicals recommended are the same used by Mr. Tanaka. I was
    taught to cover the surface to minimize penetration of the chemicals.

    Domo Arigato,


  12. Donald says:

    hello peter,
    is using a systemic insecticide mixed with a systemic fungicide any better?

    • Peter Tea says:

      Hi Donald,

      Using systemics worked great for me back in California because then I didn’t have to breath the stuff in. I asked Mr. Tanaka about it and he says that from his experiences, the systemic doesn’t work as well as the spray. Of course, that’s here in Nagoya. I believe back in our area, the systemic works great personally, I’d use that before spraying. Of course, if it’s food that’s to be consumed, I wouldn’t use the systemic at all. i.e. tomatoes.

      Take care Donald!

  13. Justin says:

    Thanks for the helpful info. I’ve had similar fungus and aphid issues here in the southern california coastal area as well. I will put your suggestions to work for me.

  14. If there is one thing that discourages me about Bonsai it is that it seems to use more chemicals than a hybrid tea rose garden. A large nursery like this is a reason to stay small. The future requires a different approach. I’m glad to see the nursery owner is handling the spray, and not subjecting a worker to this! Poor Dog! Did it get a bath, too? I worked 10 years in a retail nursery and now am quite allergic to most chemical sprays. However, I do selectively spray, and consider getting rid of trees not suited to my garden. Thanks, Peter. This is not often covered.

    • Peter Tea says:

      Hi Tom,

      I would have to agree with you there Tom! I’m not a big fan of the chemicals as well and would prefer a better safer approach, though there doesn’t seem to be a good alternative at the moment. Every time we take out the spray, I’m glad that I’m only exposed to it for a short period of time and not the rest of my life. Though that short period of time could be bad as well. LOL

      Mr. Tanaka’s has a college degree in non-toxic pest control and what he found that there is nothing out there currently that is as efficient and effective as the chemical stuff. He did added that going with the safer pest control for smaller gardens will work pretty good but difficult for large scale operations. Which is what you have pointed out in your comment as well.

      The dogs were protected from the spray so no worries there. We also made sure to clean up their watering dishes afterwards as well.

      Thanks for the comment Tom. Take care

  15. Penny Pawl says:

    Peter, we asphids, the Master Gardeners have been taught to blast them off with water so we can avoid using the pesticides. Then try afew other things before we go to sprays.

    • Peter Tea says:

      Hi Penny,

      Personally I would go with the safe non-toxic route as well before using chemicals, and that’s what I normally tell people to do as well. It just seems for large scale use, it’s difficult to find a good alternative to using chemicals at this point. Hopefully in the future, something can be found to work just as well and not affect out liver and kidneys. ;o)

      Thanks for the comment and take care Penny.

  16. Dominic says:

    Hi, Peter what is to do in case of burning the leaves as you describe ???

    • Peter Tea says:

      Hi Dominic,

      Well, if the leaves are already burned, the damage is already done. All you can really do at that point is really wash the foliage with a lot of water. That goes the same for the soil as well. Hopefully, that will at least stop any more damage from occuring. Put the tree in a shady spot and allow it to shed off the burned leaves and develop new shoots.

      Take care Dominic

  17. Michael Markoff says:

    Peter, Again thank you for this blog. I noticed 1 pic with Mr Tanaka in a Hazmat suit spray his trees amid clouds of Malathion/Daconil….and apartments directly across the street. Does he get any issues about that from his neighbors? Also, the Northeast U.S. has been blighted by phomopsis, and most bonsai enthusiasts are unaware why some junipers loose branches and tips to this fungus.

    • Peter Tea says:

      Hi Michael,

      There hasn’t been any issues with the neighbors when we spray. We do take care to warn people that we’re spraying that’s walking around and we definitely don’t spray on a windy day or at passing cars. Since we’re spraying so low to the ground for the most part, the pesticides that doesn’t stick to the tree then to land on the ground. So it’s not like the whole neighborhood is covered in a fog or anything.

      I did a bit of reading on phomopsis and something like that would be a good reason to do some preventative spraying on our Junipers. It seems like most fungicide products will work to stop the problem such as copper spray. Many people in California has switch to copper to control fungus as oppose to lime sulfur. Of course, lime sulfur was banned from sales in California a year ago or so.

      Thanks for the comment Michael. Take care!

  18. Daniel Dolan says:

    Dear Peter:

    I appreciated this topic and fortunately am virtually pest free in the Chicago area. Of course we make up for that with -20F in the winter and 103F in the summer.
    One question I do have relates to needle cast. I have read a lot…am familiar with the different kinds and the complexity that the triple banded discoloration on the needle can also indicate the trees reaction to several other conditions.

    My specific question has to do about the seasonal timing and frequency of application of whatever you use.

    Thank you.

    Midwest Bonsai Society

    • Peter Tea says:

      Hi Dolan,

      -20F is rough! 103F is rough as well!

      So far, our timing has just been more on the preventive side so it’s been monthly. We alternate different pesticides every other month or so so the bugs don’t build up a resistance. Once it gets’ warmer, we’ll start using pesticides to control spider mites only. Malathion, though advertised to kill spider mites, don’t work any more. They keep adapting to new sprays made to kill them as well.

      In the Winter time, we switch to Lime Sulfur. The good thing is that we only spray lime sulfur once during the Winter so there are a couple of months where we’re not playing with sprays which is nice. :o)

      Thanks for the comments as usual Daniel. Take care

  19. Judy Barto says:

    I understand that this is a commercial operation, and that the nursery can’t afford to loose trees, but has it ever been considered to take a more natural approach to pest control? I have trees that attract aphids, and find that ladybugs are a sufficient control.

    • Peter Tea says:

      Hi Judy,

      Thanks for the comment. Back at home, my pest problems were relatively low because of the dryer weather. When I did spray my trees, it was usually insectal soap which is very safe and non toxic. It was very rare that I actually used any type chemical pesticides.

      I talked to Mr. Tanaka and he says that we’d have to spray that weekly to control the bug problems. There are organic fungicides as well though we don’t use it. I wouldn’t let the word, “organic,” fool you either because there is an organic mercury fungicide available in Korea that is used as a fungicide whereas it’s been banned in the US. Mercury is mercury, though I have heard that it works incredibly well in treating trees that are affect by hard to kill fungus. Definitely needs to handle by a professional for sure.

      Lady bugs are a great way to control pest and used them including prying mantis as well. Interesting that you brought that up because about a week ago I was at another nursery looking at this large Japanese maple that was infested with aphids. There were many lady bugs on the tree but none of them were eating the aphids. It seemed that the lady bugs couldn’t even keep up with the aphids. LOL.

      Thanks for the comment Judy. Take care

  20. J. Dillon says:

    Very timely post for us here in Atlanta – – I’ve already made it through the first wave of aphids and this year I’m doing a good job remembering to spray my apple with fungicide to prevent powdery mildew, which has attacked it every single year I haven’t sprayed!

  21. Mark says:

    Hi Peter,
    Great post on a subject not touched on that much on treating pest in Bonsai nurseries in Japan.
    I always knew it was a major activity blasting pest, but wow, Mr. Tanaka and his high pressure sprayer takes this to a whole new level.
    I am keen to know, is there any preventative measures used at Aichi-en to reduce the build up of pests? Knowing that even after spraying like that the pest will return.

    • Peter Tea says:

      Hi Mark,

      It’s hard to say Mark because it seems like healthy strong trees are still susceptible to pest problems. Refined bonsai in Japan are difficult to take care of because they are healthy, but not allowed to be vigorous so they are more susceptible to problems then your standard tree growing in the ground.

      It seems that once the Summer comes around, the aphid problem goes down on deciduous trees whereas problems with other tree will be at it’s peak. Black Pines during the Summer can potential be attacked by spider mites. During those time, we will overhead water the foliage and bring up the humidity in the tree. Spider mites don’t like wet conditions and normally flourishes in drier environments.

      Other then that, no other tactics other then the spraying. As I continue my apprenticeship, I’ll try and gather more information on any tricks other bonsai professionals are doing and share them in another post.

      Thanks Mark!

  22. cherylas2009 says:

    I am a certified industrial hygienist and have experience with respiratory protection. To answer the question on respiratory protection, I would advise an upgrade. there are many different double banded disposable respirators with a layer of carbon or other media that are designed for pesticide application that are commercially available here in the US. I would advise an upgrade to a full or half mask cartridge respirator with the appropriate cartridges if you are applying inside a greenhouse or other enclosed space. I got my wine grape growing brother-in-law a PAPR with cartridges for his use when he sprays pesticide and fungicides. It is pricey but provides better protection.

    • Peter Tea says:

      Hi Cheryl,

      Thanks for the suggestion. I’m going to pick up a better respirator the next time I’m at the home center here in Japan and a pair of googles. Thanks!

  23. David says:

    Hi Peter,
    I guess it’s a problem everywhere around the world. I have the impression we are having more and more problems with fungus here in Belgium. Especially on maples, i hear a lot of people have really big problems to keep them healthy.
    Do they in Japan also switch products every month?
    I have a few maples in my garden and they never have problems, but the one in pot have problems from time to time. I guess it’s an advantage for the tree to grow freely in the ground to stay very healthy and fight the diseases by itself.
    Tx for sharing this very important part of bonsai, i think everybody has problems with this from time to time.

    • Peter Tea says:

      Hi David,

      Yes, trees growing in pots always seem a bit more susceptible to problems. There has been talk in Japan that pest and diseases are becoming stronger ever year and that the rise in temps is believe to be what’s causing it. Mr. Tanaka said that during his childhood, Nagoya would never get as hot is it does now in the Summer.

      What’s causing the rise in temps, well, that’s a whole big discussion/argument in itself.

      Thanks and take care David

  24. Taylor says:

    Is that simple mask Mr. Tanaka is wearing really sufficient protection from the spray? What about goggles for the eyes?

    An excellent, informative, and entertaining blog. Glad that I subscribed and thank you for blogging.

    • Peter Tea says:

      Thanks for subscribing Taylor. My feelings are that the mask doesn’t really work but I used what we had at the time. Next time I’m home, I’m going to pick up a better one, such as what Cheryl suggested in her comments. A pair of goggles is a good idea as well. Thanks!

  25. Sandy Vee says:

    Thanks again for an informative post.

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