Dormant Season Spraying Part 1: Broadleaf Deciduous Trees

Dormant Season Spraying Part 1: Broadleaf Deciduous Trees

markyscott

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markyscott submitted a new resource:

Dormant season spraying - Dormant season application of chemicals to prevent growing season issues with pests and diseases.

Application of dormant sprays have been a game-changer for me in the health of my garden. This is not meant to be an endorsement of a specific brand of spray, but rather a discussion of the steps I undertake in my garden during the dormant season to help reduce overwintering population of pests and limit the establishment of fungal diseases in the spring. Dormant spraying is a...

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markyscott

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I created this resource compiling information from a number of posts I’ve made on the subject. I’ve reposted much of this information several times in different places. Hopefully, compiling it all in a single spot and as a resource will makes it more accessible and available.
 

milehigh_7

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I created this resource compiling information from a number of posts I’ve made on the subject. I’ve reposted much of this information several times in different places. Hopefully, compiling it all in a single spot and as a resource will makes it more accessible and available.

Thank you for putting this together!
 

Mike Hennigan

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I created this resource compiling information from a number of posts I’ve made on the subject. I’ve reposted much of this information several times in different places. Hopefully, compiling it all in a single spot and as a resource will makes it more accessible and available.

Thanks for this, last winter I was banging my head against the wall trying to find lime sulphur and all I could find were one or two extremely pricy little bottles marketed specifically for bonsai use. I got one for deadwood work, but there’s no way I was going to buy a bunch of those so that I could spray my trees.

I came upon the pet dip stuff in my searches but wasn’t totally sure if it was actually lime sulfur or what the concentration was. Your article really helped me out. Will look I to the pet dip stuff again.
 

WNC Bonsai

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Hey @markyscott how about a resource on various sprays for use during the growing season. Which sprays to use for which fungi and insects and in which combinations. It seems the common response is peroxide and/or Daconil but I have not found peroxide very effective as a prophylactic spray. This is a very murky area.
 

bwaynef

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I'm pretty sure I know of a garden center that still sells Hi-Yield. I've got a bottle I haven't opened yet. Dormant oil coming Wednesday, but I'm not sure when I'll get it sprayed.
 

Panos

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Good info, try to do a bit of research about the products but we don't have them for sale here in uk
 

AlainK

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I usually spray my maples after leaf fall with a copper-based solution (Bordeaux mix), then just before budbreak. Next spring I'll alternate with lime sulfur.

For the moment, waiting for a rain-free day...
 

markyscott

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I usually spray my maples after leaf fall with a copper-based solution (Bordeaux mix), then just before budbreak. Next spring I'll alternate with lime sulfur.

For the moment, waiting for a rain-free day...

I’m sure you know, Alain, but for those who don’t. Bordeaux mix combines a copper-based fungicide with slaked lime (calcium hydroxide) - it’s usually about a 50/50 mixture. Both lime sulfur and Bordeaux mix have been in use for a long time as a dormant fungal spray. I’ts a good reminder to add a note on Bordeaux mix in the resource.

It’s probably fine to use them both, but both have their incompatiblities with other fungicides. Make sure you wait a few weeks after applying either to spray with anything else.

S
 

markyscott

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Motivated by the comment by Alain - I added a discussion about Bordeaux Mix to the resource. Thanks for the nudge @AlainK!

Scott
 

Panos

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IMG_0305.JPGIMG_0305.JPGIMG_0305.JPGThis is an elm tree, I think is 8 to 9 years old and it was growing close to my work so I decided to give him a home. It has been in a pot the last 2 years, the problem with him is that he has one long lateral root (it was a lot longer as I remember pooling the poor thing out of the ground but as the say you have to cut it away of the trunk) with no fine roots at the end of it and roughly at the half point of that long root some more fine roots emerging.... the tree is in good health leafing every year but I'm afraid the root system is not sustainable for the amount of leaves and brunches....... your opinion matters gents
 
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markyscott

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View attachment 220939View attachment 220939View attachment 220939This is an elm tree, I think is 8 to 9 years old and it was growing close to my work so I decided to give him a home. It has been in a pot the last 2 years, the problem with him is that he has one long lateral root (it was a lot longer as I remember pooling the poor thing out of the ground but as the say you have to cut it away of the trunk) with no fine roots at the end of it and roughly at the half point of that long root some more fine roots emerging.... the tree is in good health leafing every year but I'm afraid the root system is not sustainable for the amount of leaves and brunches....... your opinion matters gents


I don’t know what kind of elm you’re growing, but if it’s like any of the ones I grow, you can be a bit more aggressive with the roots and the pruning. I.e.,

https://www.bonsainut.com/threads/chuhin-broom-elm.22848/#post-343508
 

markyscott

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Today was dormant oil treatment day. I use a good quality sprayer. Forget the plastic junk at the box store. You’ll throw it away after just a few uses. Get a good quality sprayer.
8875D217-E72D-49E2-98A1-21BC3C18A1E8.jpeg

I used this oil at 5% concentration.
CBAD9882-6148-4226-9372-6438472CC61F.jpeg

At this concentration, it is effective against overwintering populations of fungus gnats, scale, aphids, gall, whitefly, apple moth, mealybugs, adelgids, and scurfy scale.

I spray everything that loses its leaves. Spray thoroughly - make sure that the entire exterior of the plant is covered. For older tridents, make sure the exfoliating bark is pealed before application to ensure a more complete coverage. Get the underside of the branches. Take your time and spray everything.
630883AF-5A69-42D7-B82D-CA56794B758B.jpeg6F74F25C-1E91-4BD5-81C1-3C5FA83132F5.jpeg

When you’re done and the spray dries, the bark will have a sheen that will fade over the next few weeks. This is normal. Don’t spray with anything else for at least 2 weeks - preferably four. In Houston, the dormant season is only about 6-8 weeks long, so its important to jump right on the dormant oil treatment as soon as possible to leave time for the lime sulfur treatment on the back end.

S
 

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Good timely information Scott. As you lived near Bremerton for a while, you know this is a bit of an epicenter for fungus in the US. Right now both new and old deadwood are covered with stuff. A163E713-7CB9-4175-A396-8FB5B1A5C749.jpeg C4EF3A19-F7AF-4A9F-94C0-46A64F68C85B.jpeg It’s even showing up on my PT wood! B911B414-DAFF-4FAA-9E6F-882346CB28B8.jpeg Do you do any treatment of your conifers with dormant sprays during the winter?
 

markyscott

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Good timely information Scott. As you lived near Bremerton for a while, you know this is a bit of an epicenter for fungus in the US. Right now both new and old deadwood are covered with stuff. View attachment 220983 View attachment 220985 It’s even showing up on my PT wood! View attachment 220984 Do you do any treatment of your conifers with dormant sprays during the winter?


LOL! - I lived IN Bremerton for awhile. And Poulsbo too!

Moisture and humidity - you and I both have them in spades. And you’re right - it’s a climate that fungal infections thrive in. So let’s talk conifers:

Pines:
There are two main fungal problems I’ve encountered on pines. Diplodia tip blight and needle cast.
For needle cast:

  1. Needle cast is a general term for a foliar disease on pine which causes small spots or lesions on needles, needle browning, death, and premature drop. It’s the most commonly reported black pine disease
  2. Caused by fungi Lophodermium, Mycospaerella, Ploioderma, or Rhozospaeria
  3. Most needle cast infect young, newly formed needles in the late spring or early summer, but symptoms do not begin to develop until the following winter or early spring
  4. First symptoms are small yellow spots on needles less than one year old
  5. Yellow spots turn brown and expand to form bands of discoloration about 1/4” wide that span the needle
  6. Tips of the needles and tissue between multiple bands will then turn brown and die - base of the needle will often stay green
  7. Infected needles will begin to prematurely drop in the late spring and throughout the summer
  8. On severely diseased trees, all needles from the previous season may be lost, leaving only new growth, weakening the tree. In later spring (April-May) stickily spores are produced on lesions from the previous year’s infections and are spread by wind or rain. Infection can only occur during wet/cool weather
  9. Treatment is a spray of copper fungicide in the early spring before the buds begin to push and spray with Daconil/Fungonil/Bravo monthly through the growing season
For diplodia tip blight (by far the most insidious because it will kill your tree no problem):
  1. The fungus which causes tip blight of pine trees is Sphaeropsis sapinea (also known as Diplodia pinea). This fungus is present throughout the year in dead needles, leaf sheaths, twigs, and cones located either on an infected tree or on the ground.
  2. Symptoms are stunted new shoots with short, brown needles still partially encased in their sheath. The buds might extend in the spring and look healthy, but will eventually wilt and die before the needles fully extend
  3. New shoots are most susceptible during a two-week period starting when the buds begin to open and continue to be susceptible until the needles harden off.
  4. Infections are worse during years with very wet spring conditions, which promotes disease infection. High humidity also promotes the germination of spores.
  5. Applications of a copper-based fungicide should be made soon as buds at the tips of the branches begin to open, with a second application 7-10 days later. Effective copper-based solutions are Bordeaux mixture, liquid copper (Tenn-Cop 5E) or fixed copper (Basic copper sulfate, Tribasic copper sulfate).
So there you have it for pines. Spray with a copper based fungicide three times in spring. First, before the buds begin to push for needle cast control. Second, for tip blight when the buds begin to open in spring. Third, for tip blight about 7-10 days after the second application. Cleary’s 3336 may also be an effective systemic supplement to this practice.

14301C4B-3E71-456E-984E-C7FABC098635.jpeg
Tip blight on pines.

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Needle cast on pines

Scott
 

markyscott

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Junipers:
The only fungal issue I’ve encountered with junipers is tip blight

  1. Caused by the fungus Phomopsis juniperovora or Kabatina or juniperi
  2. Symptoms are yellow spots on foliage, which discolors to a red, brown or gray color. Black fungal growths develop and often ooze.
  3. Phomopsis tip blight appears on young plant tissue during late spring or fall when weather is cool and wet. New plant tissue loses its color and fades to yellow or brown.
  4. Kabatina infections appear in early spring. This infection invades plants through wounds. Foliage tips remain yellow or brown during spring when the rest of the juniper's color returns to green.
  5. Spray for Phomopsis in spring and Kabatina in fall. Use Mancozeb or a fungicide containing thiophanate methyl. For Phomopsis spray when the green tips appear and again two weeks later. For Kabatina spray as the leaves are falling off the deciduous trees.
Here in Houston, I usually spray for Kabatina on junipers the same day I spray my deciduous trees with horticultural oil. Hope that helps

Scott
 

Arcto

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Junipers:
The only fungal issue I’ve encountered with junipers is tip blight

  1. Caused by the fungus Phomopsis juniperovora or Kabatina or juniperi
  2. Symptoms are yellow spots on foliage, which discolors to a red, brown or gray color. Black fungal growths develop and often ooze.
  3. Phomopsis tip blight appears on young plant tissue during late spring or fall when weather is cool and wet. New plant tissue loses its color and fades to yellow or brown.
  4. Kabatina infections appear in early spring. This infection invades plants through wounds. Foliage tips remain yellow or brown during spring when the rest of the juniper's color returns to green.
  5. Spray for Phomopsis in spring and Kabatina in fall. Use Mancozeb or a fungicide containing thiophanate methyl. For Phomopsis spray when the green tips appear and again two weeks later. For Kabatina spray as the leaves are falling off the deciduous trees.
Here in Houston, I usually spray for Kabatina on junipers the same day I spray my deciduous trees with horticultural oil. Hope that helps

Scott

Good info, thanks. The issue I’m dealing with here is the length of the fall period. There is still native deciduous plants that remain green without leaf drop. I did my “last” spray in October. Hindsight seems to be that it was too early. Spraying now is challenging due to the frequent heavy rain. This fall may just get catalogued in the experience book for the future.
 
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