Strange mite infestation, side effect of pesticides?

[Phoenikakias]

I detected mite infestation on outplanted Brahea and Sabal! Well, I believe it is mites, because I  saw webs on the backside of the blades, which, when removed by hand, were leaving a green sap on my skin (sapping bugs?). It is very strange, because those plants are there for many years, the Brahea especially for decades, and had never before had such issues. I have started considering whether the application of other pesticides against the red weevil and the giant moth caused this as side effect. I do not spray the whole crown with latter, only the apex of the palms. It can occure though, that solution drops on fronds either by accident or while I  treated taller nearby growing specimens. The pesticides I apply are 20% imidacloprid and 1% emamectin benzoat at 200 ml and 250 gr per 100 lt water respectively. Here are some pictures.

[Kim]

Yes, this looks like spider mites. I would treat with insecticidal soap and also a systemic, as it looks pretty severe. 

Edit: I do not think this is at all caused by the pesticides you used. However, as to my suggestion, I would do a soil drench with the systemic so it will be taken up in the roots and distributed throughout the palm, which kills any sucking insects. Since that takes time to be effective, the insecticidal soap should be the immediate step. Follow the directions on the product labels.

[Silas_Sancona]

Tough to say for sure... Would need better ..more detailed closeups of the pleats in the fronds ( where the webby-looking stuff seems to be concentrated. ) 

Due to the long duration, extreme heat and lack of rain ( up until recently ) have been dealing w/ spider mites- galore and they don't make mass webbing like that.  Webbing from them is usually quite fine and hard to see when taken into hand.

Certain spiders ..Jumping spiders, Sac spiders, and some others here in the U.S./ Others elsewhere  will make webs like this ( Nests for their eggs in the case of many Jumping Spiders, maybe Sac Spiders )

Some beetles and Caterpillar stages of  Moths will also make webby homes between the pleats in a palm frond,  ..or between two leaves ( Sometimes rolling them up, or drawing the two leaves together to form a tent..

If some Moth or unwanted Beetle species, simply wiping them down with a hand broom / brush will get rid of them. Can apply something like Insecticidal soap to deter them from renting space there in the future. 

As for spiders? ..You want them around..  let em' do their thing.

[Tomas]

What about Metcalfa? https://gd.eppo.int/taxon/METFPR/photos

[Phoenikakias]

2 hours ago, Tomas said:

What about Metcalfa? https://gd.eppo.int/taxon/METFPR/photos

Interesting assumption, but I do not detect sticky honeydew.

[Phoenikakias]

5 hours ago, Silas_Sancona said:

Tough to say for sure... Would need better ..more detailed closeups of the pleats in the fronds ( where the webby-looking stuff seems to be concentrated. ) 

Due to the long duration, extreme heat and lack of rain ( up until recently ) have been dealing w/ spider mites- galore and they don't make mass webbing like that.  Webbing from them is usually quite fine and hard to see when taken into hand.

Certain spiders ..Jumping spiders, Sac spiders, and some others here in the U.S./ Others elsewhere  will make webs like this ( Nests for their eggs in the case of many Jumping Spiders, maybe Sac Spiders )

Some beetles and Caterpillar stages of  Moths will also make webby homes between the pleats in a palm frond,  ..or between two leaves ( Sometimes rolling them up, or drawing the two leaves together to form a tent..

If some Moth or unwanted Beetle species, simply wiping them down with a hand broom / brush will get rid of them. Can apply something like Insecticidal soap to deter them from renting space there in the future. 

As for spiders? ..You want them around..  let em' do their thing.

New evidence, this time on the leaf backside of a Trachy. These are the best close ups I could shoot.

Edited August 9, 2023 by Phoenikakias

[Silas_Sancona]

1 minute ago, Phoenikakias said:

New evidence, this time on the leaf backside of a Trachy. These are the best close ups I could shot.

Was thinking i saw some Scale at first ( may be some hanging out on the effected fronds too regardless.. ) but i can see some brownish, rice grain- shaped Pupae " shells " in some of the pictures, which makes me think the culprit creating the  " webs " might be some sort of small moth .. with the white / brown grainy-looking stuff being accumulated Frass ...AKA: Caterpillar poop that gets trapped in the webby stuff over time as they grow, but remain in the same basic spot as they develop.. 

Admittedly,  not well acquainted with insects on that side of the world, so i can't say exactly what kind of moth it could be but there are many possibilities.  All would be small and hardly noticeable as an adult, and the Caterpillars will be tiny.. With some, the Caterpillars eat by scraping at the surface of a leaf while others might bore into a thicker rib between two leaves.

  Some sort of tiny Beetle could be another possibility.  Some larvae of various sps will live in a silken nest on a leaf until they pupate into the adult stage,  and poop all over their home as they develop..

Certainly possible spider mites.. ( They like somewhat shaded spots where there is very little air movement, esp. where dust can collect )  are hanging out too..  Good way to find out?   If possible,  is to knock a suspect frond against a dark sheet of paper (  ..or a sheet )  then watch to see if any of the tiny bits that land on that surface start to move around.. 

While they're tiny,  you can still see them moving about on a darker surface if present.

Regardless, as mentioned, you can take a hand brush to the fronds, or blast with water to clean them off,  ...then treat with something to keep them from coming back / break their life cycle..  Keeping the fronds cleaned up / washed down so dust won't settle on them for long will deter the web creators from settling in again too.

As i'm sure you know,  w/ spider mites,  just because you kill the adults doesn't mean you will eliminate the problem right away..  Often, You'll have to repeat a treatment every so many weeks to kill any / all nymphs that emerge after the adults have been killed since, if you don't, that next generation will try to establish themselves / restart the cycle.  Spider Mites will lay their eggs in the soil, rather than on leaves which is one reason they're not always the easiest of pest insects to get under control. 

[Tomas]

3 hours ago, Phoenikakias said:

New evidence, this time on the leaf backside of a Trachy. These are the best close ups I could shoot.

Definitely not Metcalfa. Eggs below web, wait, they will be born soon. That would be the heaviest infestation of RSM I have evwr seen 😟

Edited August 9, 2023 by Tomas

[Phoenikakias]

3 hours ago, Tomas said:

Definitely not Metcalfa. Eggs below web, wait, they will be born soon. That would be the heaviest infestation of RSM I have evwr seen 😟

Some new pictures after I rinsed off the webs and treated with abamectin. Tomas it is very difficult for me to accept that a Brahea was affected by spider mites in my garden, at least without any other crucial factors concurring.

In case it has not become obvious, fitst picture shows green sap on my fingers. Second adaxial leaf side of S. bermudana and last picture abaxial leaf side of Trachycarpus ukhrulense.

[sonoranfans]

Hekko Kostas greetings from florida!  Imidacloprid has been reported to impact the soil microbiome in a negative way.   I would be very careful applying it if you apply it at all.  If the soil microbiome is badly impacted and the plant is stressed, it will lower its natural defense mechanisms.  Any badly stressed plant will struggle to defend itself.  I have seen genetically identical hemp clones that can exhibit drastic differences in pest and pathogen resistance due to waterlogged soil(kills off microbiome) as compared with healthy soil.  This article supports the hypothesis that imidacloprid can potentially impact plant defense by stress related lowering of its chemical defenses(enzymes, terpenoids).   https://pubmed.ncbi.nlm.nih.gov/25597673/

 

[Phoenikakias]

8 hours ago, sonoranfans said:

Hekko Kostas greetings from florida!  Imidacloprid has been reported to impact the soil microbiome in a negative way.   I would be very careful applying it if you apply it at all.  If the soil microbiome is badly impacted and the plant is stressed, it will lower its natural defense mechanisms.  Any badly stressed plant will struggle to defend itself.  I have seen genetically identical hemp clones that can exhibit drastic differences in pest and pathogen resistance due to waterlogged soil(kills off microbiome) as compared with healthy soil.  This article supports the hypothesis that imidacloprid can potentially impact plant defense by stress related lowering of its chemical defenses(enzymes, terpenoids).   https://pubmed.ncbi.nlm.nih.gov/25597673/

 

Tom, you are a treasure of knowledge. I never apply imidacloprid by soil drenching, if not for any other reason but surely because I do not trust, that substance will travel fast enough up to plant's apex, where most infestation incidents take place. instead I spray directly from over the apex downwards with the help of an extension pole. Given tbe severity of threat that red weevil and giant moth present for my palms and the odds for an infestation, I really have no other affordable alternative. Nevertheless I am aware, that the practice of a monthly spraying of all palms for many years eventually must have taken its toll regarding my some if my plant losses.

[Phoenikakias]

On 8/9/2023 at 10:44 AM, Silas_Sancona said:

Was thinking i saw some Scale at first ( may be some hanging out on the effected fronds too regardless.. ) but i can see some brownish, rice grain- shaped Pupae " shells " in some of the pictures, which makes me think the culprit creating the  " webs " might be some sort of small moth .. with the white / brown grainy-looking stuff being accumulated Frass ...AKA: Caterpillar poop that gets trapped in the webby stuff over time as they grow, but remain in the same basic spot as they develop.. 

Admittedly,  not well acquainted with insects on that side of the world, so i can't say exactly what kind of moth it could be but there are many possibilities.  All would be small and hardly noticeable as an adult, and the Caterpillars will be tiny.. With some, the Caterpillars eat by scraping at the surface of a leaf while others might bore into a thicker rib between two leaves.

  Some sort of tiny Beetle could be another possibility.  Some larvae of various sps will live in a silken nest on a leaf until they pupate into the adult stage,  and poop all over their home as they develop..

Certainly possible spider mites.. ( They like somewhat shaded spots where there is very little air movement, esp. where dust can collect )  are hanging out too..  Good way to find out?   If possible,  is to knock a suspect frond against a dark sheet of paper (  ..or a sheet )  then watch to see if any of the tiny bits that land on that surface start to move around.. 

While they're tiny,  you can still see them moving about on a darker surface if present.

Regardless, as mentioned, you can take a hand brush to the fronds, or blast with water to clean them off,  ...then treat with something to keep them from coming back / break their life cycle..  Keeping the fronds cleaned up / washed down so dust won't settle on them for long will deter the web creators from settling in again too.

As i'm sure you know,  w/ spider mites,  just because you kill the adults doesn't mean you will eliminate the problem right away..  Often, You'll have to repeat a treatment every so many weeks to kill any / all nymphs that emerge after the adults have been killed since, if you don't, that next generation will try to establish themselves / restart the cycle.  Spider Mites will lay their eggs in the soil, rather than on leaves which is one reason they're not always the easiest of pest insects to get under control. 

Breaking news, this tiny black bug is the culprit it is certain. And it can fly or at least hop! Any idea?

[Silas_Sancona]

12 minutes ago, Phoenikakias said:

Breaking news, this tiny black bug is the culprit it is certain. And it can fly or at least hop! Any idea?

  The Beetle itself ( Looks like that's what it is ) won't create the webbing, ..but,  it's caterpillar-like larvae certainly could..