Fungal Issues or Slight Sunburn?

[Apex37]

I noticed my azalea recently has what appears to be blotchy brown spots that I suspect may be caused from slight sunburn or a fungal issue. I’m leaning towards sunburn though and just want some second opinions. Planted in 100% kanuma. I’ve been watering about every 2-3 days depending on needs.

 

[Wires_Guy_wires]

First two pictures look like thrips damage.
Last one probably mechanical.

 

[Apex37]

First two pictures look like thrips damage.
Last one probably mechanical.

Thrips are new for me, but after looking at pics of damage they cause, and a few other plants in the garden, I believe you may be correct and I think I have a few plants affected. I’ll treat accordingly. Thank you!

 

[JudyB]

I immediately thought thrips too.

 

[Apex37]

I treated with Malathion but it appears that this issue is getting worse. I could use any guidance as I would be really really sad if I lose this one.
Calling @Deep Sea Diver since I know you deal a lot with satsukis.

 

[Deep Sea Diver]

Ouch. Very sorry to see this.

Looks like either leaf or partial root damage from the Malathian. It’s a thing.

Two issues now. Possible leaf +/or root damage. Possible left over thrip infestation.

Can tell you what I’d do …given the tree is strong enough and treated well. No promises.

Have these items ready.

1. Safer soap (Can alternate with need oil if desired),
2. moss,
3. media,
4. toothbrush,
5. plastic wrap,
6. nitrile gloves - mask - safety glasses
7. a cool place with bright shade for tree with no sun. Use 50% shade cloth if needed to help. Thrips love heat.

Step by step

• Use gloves. Cut off the most severely damaged leaves back to the next green part.
• Any leaf that is mostly ok and has brown on it, cut off the affected part, leaving the rest of the leaf. If in doubt, cut it out.
• Remove all the moss and gently scrape off the top media. (Thrips tend to hide/overwinter in surface media and debris as well as and nooks and crannies of the plant)
• Clean tools frequently
• Spray toothbrush with Safer soap. Use toothbrush to gently scrub all the hard parts of the nebari. Then cover the media and nebariwith plastic wrap
• Scrub trunk and top and bottom of branches gently but thoroughly, especially the junctions. Keep the toothbrush wet with soap.
• Spray fingers with Safer soap and gently rub top and bottom of leaves affected.
• Gently wash top foliage, trunk, branches and leaves with water.
• Remove plastic wrap. Spray media thoroughly with Safer Soap. Wait an hour and flush media with water.
• Remoss media, flush and chock up one side of the pot to fully drain, place flat. Spray moss with Safer soap.
• Spray work area, any plants and benches where the azalea was stored with safer soap.
• Place azalea in cool, bright shade spot away from other plants.
• Mist 3-4x a day. Only water when moss is slightly damp. Then water thoroughly. (Want to maximize the O2/H2O exchange.) Be sure to mist later, but ensure leaves are dry by sundown
• Spray thoroughly with safer soap each week to disrupt the thrip 2-3 week life cycle. Continue for 7 weeks to treat two full life cycles..
• Fertilize with 1/4 strength liquid fertilizer after 1 week and every 10-14 days after. Include foliage.
• Since thrips are present would preventatively spray safer soap or neem oil on any broadleaf plants every two weeks. Ensure plants sprayed with neem oil are kept out of the sun for six hours, or sprayed overnight.

This is such a lengthy post. Sorry! It’s a toss everything including the kitchen sink at the issue kind of situation

Will keep our fingers crossed. Please post progress.

PS: In the future please go to the least harmfull option first, Safer soap and Neem oil. Even if it doesn’t totally solve the problem, likely the plant won’t be severely injured if one takes quick action . Also Pyrethrin is generally considered the effective nuclear choice for azalea and rhododendrons with thrip issues. Use carefully.

Whew! Wishing both the azalea and yourself the best of luck!

cheers
DSD sends

​

 

[Apex37]

Ouch. Very sorry to see this.

Looks like either leaf or partial root damage from the Malathian. It’s a thing.

Two issues now. Possible leaf +/or root damage. Possible left over thrip infestation.

Can tell you what I’d do …given the tree is strong enough and treated well. No promises.

Have these items ready.

1. Safer soap (Can alternate with need oil if desired),
2. moss,
3. media,
4. toothbrush,
5. plastic wrap,
6. nitrile gloves - mask - safety glasses
7. a cool place with bright shade for tree with no sun. Use 50% shade cloth if needed to help. Thrips love heat.

Step by step

• Use gloves. Cut off the most severely damaged leaves back to the next green part.
• Any leaf that is mostly ok and has brown on it, cut off the affected part, leaving the rest of the leaf. If in doubt, cut it out.
• Remove all the moss and gently scrape off the top media. (Thrips tend to hide/overwinter in surface media and debris as well as and nooks and crannies of the plant)
• Clean tools frequently
• Spray toothbrush with Safer soap. Use toothbrush to gently scrub all the hard parts of the nebari. Then cover the media and nebariwith plastic wrap
• Scrub trunk and top and bottom of branches gently but thoroughly, especially the junctions. Keep the toothbrush wet with soap.
• Spray fingers with Safer soap and gently rub top and bottom of leaves affected.
• Gently wash top foliage, trunk, branches and leaves with water.
• Remove plastic wrap. Spray media thoroughly with Safer Soap. Wait an hour and flush media with water.
• Remoss media, flush and chock up one side of the pot to fully drain, place flat. Spray moss with Safer soap.
• Spray work area, any plants and benches where the azalea was stored with safer soap.
• Place azalea in cool, bright shade spot away from other plants.
• Mist 3-4x a day. Only water when moss is slightly damp. Then water thoroughly. (Want to maximize the O2/H2O exchange.) Be sure to mist later, but ensure leaves are dry by sundown
• Spray thoroughly with safer soap each week to disrupt the thrip 2-3 week life cycle. Continue for 7 weeks to treat two full life cycles..
• Fertilize with 1/4 strength liquid fertilizer after 1 week and every 10-14 days after. Include foliage.
• Since thrips are present would preventatively spray safer soap or neem oil on any broadleaf plants every two weeks. Ensure plants sprayed with neem oil are kept out of the sun for six hours, or sprayed overnight.

This is such a lengthy post. Sorry! It’s a toss everything including the kitchen sink at the issue kind of situation

Will keep our fingers crossed. Please post progress.

PS: In the future please go to the least harmfull option first, Safer soap and Neem oil. Even if it doesn’t totally solve the problem, likely the plant won’t be severely injured if one takes quick action . Also Pyrethrin is generally considered the effective nuclear choice for azalea and rhododendrons with thrip issues. Use carefully.

Whew! Wishing both the azalea and yourself the best of luck!

cheers
DSD sends

​

Thanks DSD! I think going forward I’ll stick to just insecticidal soap, manual removal, and at worst use something like pyrethrin (which ironically I almost used instead). I only used Malathion because it said safe to use on azaleas, but obviously that’s dependent on a lot of factors and tender new leaves being the obvious outlier. I’m not super familiar with pesticide use with azaleas and not many of my club members grow them for whatever reason, even though I know other clubs locally grow them with great success. I really appreciate your feedback and suggestions. I’ll give it a try and hope for the best. This is one of my nicer trees and I’d hate to lose it.

Thanks again 100x’s and I’ll continue to update as we progress.

 

[Deep Sea Diver]

No worries.

btw @Chuah is a noted bonsai azalea person down in Houston area. Ho really knows the ins and outs of working with azaleas in warm weather. Might be worth your time to check in with him on occasion to,

Cheers
DSD sends

 

[Paradox]

@Deep Sea Diver
This kind of damage with just malathion or have you seen this with other products? Pyrethren considered safer?

Curious in case I ever need to treat my azaleas. Read the above advice. Understand using the escalated approach for things.

I really hope this one pulls through for Apex

 

[Chuah]

No worries.

btw @Chuah is a noted bonsai azalea person down in Houston area. Ho really knows the ins and outs of working with azaleas in warm weather. Might be worth your time to check in with him on occasion to,

Cheers
DSD sends

Thank you John. Happy to share what I know. So glad to see more and more people in Southeast Texas getting into azaleas and growing them successfully.

 

[Deep Sea Diver]

Personally don’t think either hazardous chemicals are safer. Just double edged tools.

Pyrethrin is recommended most by azalea folks, it can work and seen this, yet it’s the nuclear option. Once one gets to last resort, you have to accept anything from there on stoically. It can work… it’s it’s nasty though see sds beliw

https://labelsds.com/images/user_uploads/Bonide Pyrethrin SDS 11-6-20.pdf

We avoid Malathion due to a number of things one of them is possible cancerous effects on humans etc. (See the sds below if you would like more info on this.)

https://labelsds.com/images/user_uploads/Malathion Insect Control SDS 11-1-21.pdf

Have seen leaf burn, esp. on tender or damaged leaves before with associated root damage. Often comes from multiple passes or uneven spraying or over lap. Root burn comes from the same, including dripping from the leaves’

What make thrips such a burden is they burrow into nooks and crannies, even into leaves and overwinter in the debris and moss and top later of media. Likely were there a little last year and came out in full force this spring.

In this case the leaves were already damaged a lot. So keeping fingers crossed.

Cheers
DSD sends

 

[Deep Sea Diver]

Thank you John. Happy to share what I know. So glad to see more and more people in Southeast Texas getting into azaleas and growing them successfully.

Thanks Ho,

Can you please relate any experience you’ve also had with thrips in Texas?

Cheers
John sends

 

[Chuah]

I noticed my azalea recently has what appears to be blotchy brown spots that I suspect may be caused from slight sunburn or a fungal issue. I’m leaning towards sunburn though and just want some second opinions. Planted in 100% kanuma. I’ve been watering about every 2-3 days depending on needs.
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Just adding my two cents to what Deep Sea Diver wrote. Looks like you have thrips and fungal issues. If you want to go organic, dipotassium salts of phosphoric acid such as GardenFos is very effective for controlling fugal growth in azalea, it is also systemic. It is also great for treating phytophora root rot. For thrips, especially chili thrips, Spinosad, a derivative of rum is very effective.

 

[Chuah]

Thanks Ho,

Can you relate any experience you’ve also had with thrips in Texas?

Cheers
John sends

John,
I just wrote a reply for Apex 3 about using GardenFos and spinosad for treating azalea fungal growth and thrips for organic treatments. Best protection of thrips is to apply imidaclopid in early spring like March in my area.

 

[Deep Sea Diver]

Thank you!

Cheers
DSD sends

 

[Apex37]

Just adding my two cents to what Deep Sea Diver wrote. Looks like you have thrips and fungal issues. If you want to go organic, dipotassium salts of phosphoric acid such as GardenFos is very effective for controlling fugal growth in azalea, it is also systemic. It is also great for treating phytophora root rot. For thrips, especially chili thrips, Spinosad, a derivative of rum is very effective.

Thanks Dr. Chuah! I’m actually part of the Fort Worth club and my very first meeting was when your wife did that demonstration on kusamono about 2 years back. I appreciate your help and have enjoyed reading your blog. I hope this one pulls through and will try out those suggestions.

Thanks again,
Caleb

 

[Chuah]

Thanks Dr. Chuah! I’m actually part of the Fort Worth club and my very first meeting was when your wife did that demonstration on kusamono about 2 years back. I appreciate your help and have enjoyed reading your blog. I hope this one pulls through and will try out those suggestions.

Thanks again,
Caleb

Hi Caleb,
will you be coming to Houston for the convention? If so, looking forward to seeing you. We can talk more about azalea.

 

[Apex37]

Hi Caleb,
will you be coming to Houston for the convention? If so, looking forward to seeing you. We can talk more about azalea.

I wish I could make it down, but unfortunately have other commitments that weekend. I hope it goes well though!

Caleb