Spider mites on brugmansia

[Than]

I have become desperate with this little tree I have in a pot. It seems to be a pest magnet. Everything from caterpillars to spider mites loves it. I have been spraying it with abamectin the last few weeks but to no avail. It's losing its leaves fast and I think it's going to die soon. I guess that the hairy leaves make it easier for mites to hide.  Abamectin seems to work with all other plants but this one. I checked some leaves under a microscope today and mites are alive and well. I wiped the leaves with wet tissue today.  I have tried neem but it burnt some leaves.

What I don't get is that it seems to be a very common plant in gardens here, yet I have been so unsuccessful with it. The growth rate is appalling due to all the pests.

Is there some pesticide or technique I can use instead which works? I'd rather use something I can water with, rather than spraying; this way the pesticide will stay in the pot and the plant and won't spread to the air, the other plants and myself. 

 

[frankcar1965]

They want copious water then fertilizer, lack of water often exacerbate SP, is it dark green or lighter yellow green? Dark green means it's getting enough nitrogen. I look at mine now and should fertilize it, you just reminded me!

[Silas_Sancona]

2 minutes ago, frankcar1965 said:

They want copious water then fertilizer, lack of water often exacerbate SP, is it dark green or lighter yellow green? Dark green means it's getting enough nitrogen. I look at mine now and should fertilize it, you just reminded me!

Agree w/ this 100% ..These are water HOGS   ..Good air movement deters Spider Mite issues as well..

As far as Fert?  Need all three macros  but, as w/ pretty much any plant,  too much N = lots of green growth / few ..or no.. Flowers..

Keep the K high ..12-22% range,  if you want flowers ...and better resistance to weather - related stressors.

[Than]

The leaves turn yellow and die due to the mites right now. I cut most leaves.  A professional told me that abamectin has to be alternated with some other pesticide or the mites grow resistance to it. I will wipe the remaining leaves daily with a wet cloth. 

I am also trying to find info about submerging the whole plant in water for some minutes. Perhaps this will keep the mites?

I have realized it wants lots of water. I normally water every day and keep water in the tray. I fertilize every 3 weeks.

@Silas_Sancona you must have a spider mite festival in the summer in your hot and dry climate!

[Silas_Sancona]

21 minutes ago, Than said:

The leaves turn yellow and die due to the mites right now. I cut most leaves.  A professional told me that abamectin has to be alternated with some other pesticide or the mites grow resistance to it. I will wipe the remaining leaves daily with a wet cloth. 

I am also trying to find info about submerging the whole plant in water for some minutes. Perhaps this will keep the mites?

I have realized it wants lots of water. I normally water every day and keep water in the tray. I fertilize every 3 weeks.

@Silas_Sancona you must have a spider mite festival in the summer in your hot and dry climate!

I do ..if i don't wash leaves / keep things watered, and don't place vulnerable things where there is more air movement..  And only this time of year ..More of an issue in late April - mid June than now, even though it is hot.  They can show up on a few things i bring in for a couple weeks in winter some years as well..

When dealing with them, absolutely no pesticides allowed. They become resistant to it pretty easily.  I handle them the way nature handles most things..  Increased water,  increased air movement, and periodic washing of leaves  / removing them if i need to.. Dusty leaves = the perfect set up for the little buggers.


And no, submerging an entire plant won't completely knock them out.. Spider Mites lay eggs in the soil  So, while submerging something may knock out adults,  hatchlings that emerge later will start another cycle.  Have to break both  of those cycles.

Too much fert,  esp if high in N = lots of nice, delicious new growth Spider mites ( and other sap suckers ) love. 

[frankcar1965]

I have to disagree about nitrogen, it's all I give mine, lawn fertilizer, usually summer lawn fertilizer since it has more K in it for supposed heat tolerance.  Lawn fertilizer is basically nitrogen, mine has buds on it right now.

[Than]

8 hours ago, Silas_Sancona said:

I do ..if i don't wash leaves / keep things watered, and don't place vulnerable things where there is more air movement..  And only this time of year ..More of an issue in late April - mid June than now, even though it is hot.  They can show up on a few things i bring in for a couple weeks in winter some years as well..

When dealing with them, absolutely no pesticides allowed. They become resistant to it pretty easily.  I handle them the way nature handles most things..  Increased water,  increased air movement, and periodic washing of leaves  / removing them if i need to.. Dusty leaves = the perfect set up for the little buggers.


And no, submerging an entire plant won't completely knock them out.. Spider Mites lay eggs in the soil  So, while submerging something may knock out adults,  hatchlings that emerge later will start another cycle.  Have to break both  of those cycles.

Too much fert,  esp if high in N = lots of nice, delicious new growth Spider mites ( and other sap suckers ) love. 

It's very windy here so air movement isn't an issue and I water a lot. 

What's your experience with neem oil?

[Silas_Sancona]

Just now, Than said:

It's very windy here so air movement isn't an issue and I water a lot. 

What's your experience with neem oil?

Don't use it myself.  Whenever i see spider mites, i'll pull the effected plant out and wash it down w/ the hose. ..Then repeat a couple more times if i see them trying to establish themselves again.  

One thing to remember is be careful using it, can burn leaves if applied at the wrong time of day.

Note the Hot / Warm days,  and  " too often " sections of this article:
https://backyardgardengeek.com/neem-oil-plant-burn/


 

[Than]

6 hours ago, Silas_Sancona said:

Don't use it myself.  Whenever i see spider mites, i'll pull the effected plant out and wash it down w/ the hose. ..Then repeat a couple more times if i see them trying to establish themselves again.  

One thing to remember is be careful using it, can burn leaves if applied at the wrong time of day.

Note the Hot / Warm days,  and  " too often " sections of this article:
https://backyardgardengeek.com/neem-oil-plant-burn/


 

I burnt a plumeria once in Bali by spraying with alcohol+water on midday... I was a new gardener back then.

Today I spotted spider mites on another plumeria. I would like to spray tonight with neem oil but with 30 C at midnight, not sure it would be a good idea. I guess I will have to wait for September when the next humane temperatures are expected...

What do you do if you have mites on a tree I wonder...  You cannot wash a whole tree with a hose I guess

[Silas_Sancona]

7 hours ago, Than said:

I burnt a plumeria once in Bali by spraying with alcohol+water on midday... I was a new gardener back then.

Today I spotted spider mites on another plumeria. I would like to spray tonight with neem oil but with 30 C at midnight, not sure it would be a good idea. I guess I will have to wait for September when the next humane temperatures are expected...

What do you do if you have mites on a tree I wonder...  You cannot wash a whole tree with a hose I guess

Plumeria, particularly those kept under the front or back porch, are the only ones i'll see spider mites show up in..  Washing off with a good squirt w/ the hose a coupe times seems to eliminate them.

Potted specimens i keep under the Ficus out back, and the one planted for a few years now have never had issues.

Sunburn follows an odd pattern.. Potted specimens under the front porch ( faces due east ) have been showing burn, even though they only see sun for a few hours in the morning.. Others i have under the Ficus have been showing some yellow blushing ...from the sheer magnitude of the heat ..but are otherwise green. ..Same w/ the bigger, planted specimen ( filtered shade all day until the sun moves west over the roof ).

Smaller in - ground specimens that are seeing much more sun are a bit crispy atm ..but pushing through it.

Overall, notice that the worst Spider Mite issues i'll see each year arise on Morning Glories that pop up before the rains kick in now / heat backs off in late Aug. / Sept. Growth rate increases considerably as the heat backs off  as well.   ..and on a Brunfelsia  i've had for over 12 years that sits under the back patio where air flow is pretty poor. 

It gets nailed w/ mites every late May - June,  but, if i squirt it down every couple weeks to remove accumulated dust, and keep it watered, Spider Mites disappear ..or their presence is greatly reduced.

Unless a tree is really sick / stressed  ..or in the worst possible place w/ little or no air movement ( ..where it would likely die anyway ) don't think spider mites, let alone all the other insects that do their thing in trees  bother them.

[Than]

After spraying with neem oil (in the evening), things became much worse. I am not sure if it is because of the neem oil or it would happen anyway. I put the plant in a western facing balcony to keep it away from other plants and perhaps the strong afternoon sun did this.. I wonder if it is a goner. I cut the ends that looked worse. It's been indoors since yesterday and the soil is constantly wet but no improvement.