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I love the Smell of Pesticides In the Morning!

Updated: Oct 8, 2020

I love the Smell of Pesticides In the Morning!

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 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

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!


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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