Sanderianum seedling leaf problems

[Dandrobium]

Hey guys! I've been keeping this sandy seedling alive since May and after losing a lower basal leaf, its finally starting a new one! I believe the plant is stressed from something, I know I need to change some culture condition for it to thrive.

Its got some spotting happening on the underside of its leaves and I'm not sure what is causing it:

I did have a Phal closeby that had Fusarium, but I've since isolated that plant. Also been dealing with fungus gnats lately. I've treated all plants with a mixture of Thiomyl and Azamax, which seems to help but the gnats seem to come back after a few weeks.

Thanks for any help!

 

[musa]

Hello,

that looks very much like a problem with spidermites to me. Probably it is false spidermite (tenuipalpide). These are tiny red spots which you only can see with a magnificationglass. They dont produce webs, reproduce slowy but as they are too little to see, you first recognize the damage at a very late stage.
If you can varify mites I would sugest to repot and use a strong akarizide (antimite) like acequinocyl (dont know if it is allowed by your regulations) on all parts of the plant. To get rid of the pest and to avoid resistences use a second akarizide within 7-10 days.
Seems to be a hard procedure but in my opinion tenuipalpide are one of the worst pests you can have.

Good luck!

Michael

 

[Paphman910]

looks like mite infestation. Better treat it right away.

 

[fibre]

I agree. Some kind of mites. I'm sorry but I would toss the left over part of this plant into the compost bin. It isn't worth any effort. You better try to restart with a healthy new one.

 

[Dandrobium]

Thank you for your suggestions. I'm on the fence with this one, I'd like to treat it, as it has begun a new leaf and is finally showing evidence of growth. But I realize this damage could set it back a ways. We'll see...

 

[Kostas]

I see no harm in trying to get it healthy again. You could move it outdoors to help it with the notes but the best solution is predatory mites. You release them in your growing space and say goodbye to spider mites and fungus gnats...And no toxic pesticides to harm you either

 

[musa]

Predatory mites are a good thing for prevention of mites but in this case you probably need a fast solution of the problem if you dont want to loose the plant, that means chemicals.
Michael

 

[Paphman910]

Predatory mites are a good thing for prevention of mites but in this case you probably need a fast solution of the problem if you dont want to loose the plant, that means chemicals.
Michael

Totally agree. You could use Azamax from General Hydroponics. It is an extract of the active ingredient of Neem oil. Very effective against insects and mites and has no scent that I can detect. An AOS judge told me about it.

 

[Kostas]

Predatory mites are cheap and can come in big quantities which are an instant solution for a good many infected plants, not just a tiny infected one like this. After all, we seldom care to introduce any insect unless we got a problem

For an immediate solution, you can spray the leaf underside with plain water 2 times a day and they hate it big time. Just make sure the water evaporates in a couple hours or sooner to not cause any rot problems

 

[musa]

Hello Kostas,

I am very sorry but I strongly disagree with you.

The only predator mite which can be used as a quick solution of pests are Phytoseiulus persimilis. They only kill the common spidermites (tetranychus).
But in this case the Problem are false spidermites (tenuipalpide). Against These you could uso only amblyseius californicus or amblyseius swirsky. Both are advised to use exclusively prophylactic and not in case of emergency.
You will find lots of reliable information about it in the Internet.

And also I am quite sure that pure water wont do it.

I agree with you, that chemicals should be avoided when ever possible, but to save a sanderianum I would strongly advise them.

Michael

 

[Kostas]

Hello Michael,

I am not familiar with the action of Amblyseius against false spider mites so i will take your word for it. Generally, if the enemy is well matched to the target insect, you can use a bigger quantity and for an established problem and get rid of it quickly. This also helps establish predatory insect colonies faster.

Pure water would be mainly for keeping them under control till predatory mites can be released

Best,
-Konstantinos

 

[Wendy]

I don't use anything but a horticultural oil mix for spider mites. Being a windowsill grower I have to deal with mites in a dry home environment. I mix 10-15 ml or horticultural oil with 1 litre of water, shake well and spray the plant. I do this once every couple months and it keeps the mites at bay. I've done it for years and it works. When I had my indoor grow room I used an electric hand held paint sprayer to apply it; now I just use a hand held spray bottle.

 

[Dandrobium]

Thanks for all your suggestions! I haven't seen any evidence on the rest of my collection, so I don't think I need to go and "release the hounds" ...yet. I'm going to continue using Azamax but also pick up some paraffinic oil to spray down.
Where would one get predatory mites if I were to battle a major infestation?
Again, a big thanks to everyone!

 

[musa]

Hi Dandrobium,

if there will be a Major infestation you should unleash hell, as told. If you want to try predators do it before the problem emerges.
You just have to make sure the predatory mites get the right conditions to survive (high temp and high humidity). A. swirsky has another Advantage: they can feed on many things even on pollen, so they wont starve if there are no mites. I dont know your growing conditions but it is told, that it is more than difficult on the window sill.
In Europe you can order the mites in onlinestores, I guess that's possible in Canada as well. As it is a living product it will be difficult to Import them.

Good Luck again

Michael

 

[Happypaphy7]

I might add some more info on false spider mites.
Water might help detach the bugs mechanically, but it is not useful and with enough pressure to detach them off the plant, I'm afraid the plant tissue might be all bruised.

False spider mites love water!
Red spider mites thrive under hot and dry conditions.
False spider mites (Brevipalpus phoenicis) thrive under warm to hot plus very humid (80-90) conditions.

In drier home conditons, they will still thrive, but the life cycle won't repeat as often and fast as it could under more favorable conditions, which is warm and very humid conditions.

Look closer on the plant surface and you should be able to see them, and even eggs.
Yes, they are very small, much much smaller than spider mites, which I have no problem seeing at a distance.
When I first saw false spider mites, I thought they were just some dust particle, but they were moving. They move much slower than red spider mites too, but they move around. That's when I knew what I was looking at.

With plants like multi floral paphs and other orchids like certain dendrobiums, it is quite easy to see them. Ok, some people may never be able to see them with naked eyes, but they are big enough to be seen.
I repeat, they look like a tiny little dot. They don't look like a bug to naked eyes.

With paphs like parvi or others with darker underside, it is pretty much impossible to spot them. One might see the damage showing up when there are these mites.

So far, I have only seen them on In-Charm Handel and some dendrobiums, and oncidium hybrids. With ondiciums, I tried washing leaves down with soap and alcohol, but with so many leaf crevises due to plant design, it's nearly impossible to get rid of them. Plus, the oncidiums I had were easily replaceable mericlones, so I threw them all away in fear of having mites spread on to other plants, more precious ones like paphs, one of a kind orhicds, right?

With Dendrobiums, it is very easy to wash down the plants, so I was able to eliminate them after a few washing with a few days interval between washing.

Now, paphs are also nearly impossible to wash down with the way the leaves are.
I sprayed neem oil based spray from home depot, and it worked.
This was all a couple of years ago.
I still take a very close look at the underside of the plants, all plants just in case.
I hate mites.

By the way, neem oil seems to cause a lot of burning issues on most other paphs and orchids for me.
So I wonder that product mentioned above, Azamax, if that product has any side effects.

So the bottom line, use chemicals that you can find.
Plus, in the meantime, I recommend what I did.
Each time you water your plant, wash the leaves with soapy water. It should help detach the mites off the plant. That would be about twice a week, right?
That really works great althought it sounds tedious.

 

[Dandrobium]

I finished my second drench with Azamax a couple days ago and I haven't noticed any issues with any of my plants. Thankfully, all of the fungus gnats are gone but it didn't provide an immediate kill. For that, I gave my trays a shake and anything airborne I hit with safer's soap :viking: Seemed to do the trick! I also used SS on the underside of the Sandy leaves lately.
So far so good, haven't seen any additional evidence of pests. I think as a preventative, I'll start rotating sprays (Neem, SS, hort. oil) on the leaves once or twice a month, at least during the warmer months.

 

[Happypaphy7]

Azamax is a drench? not a spray?

Well, good thing things are under control now.

Good luck!

 

[Dandrobium]

It can be used as a drench or a spray: http://www.generalhydroponics.com/genhydro_US/product_labels/AzaMax.pdf