Can someone please tell me if this is a case of Spider mites?

Tiny yellow dots are appearing on a few leaves on each of my 2 plants. They seem to be in patches, and i've closely inspected the underside of the leaves and cant see anything, looks normal and healthy. Have never seen any insects, or webs.

Plants are going into their 4th week of veg, under a 400W MH.

Journal of grow so far can be seen in signature

Can someone tell me what this is and what to do about it.



Thanks in advance

I think spider mites usually lay there eggs on the bottom side of the leaves. That could be mold or trichomes

How would mold only appear on some leaves and in patches though? The only time humidity is high enough for mold is when i give my plants a misting for half an hour every morning, but even then i open the doors after 15 mins to air the cupboard and turn the intake fans on straight after for the dark period for fresh air circulation. By the time i open the cupboard again all the leaves are dry.

With regards to trichomes i thought they only develop in the flowering stage. Also why would they be appearing on random leaves in patches?

Cheers for the quick reply

I don't know... the first pic makes me think it's mites. But you're not seeing anything under the leaves? The mites are really small - maybe the biggest ones would be the size of one of those specks in pic 1, and many would be smaller (really hard to even see).
If it was me, I'd invest the $10-$15 for one of those little hand held microscopes from radioshack and have a really good look at the undersides of those leaves.
I'm skeptical of trichomes or mold... doesn't look like it to me. But, maybe it's something else that I''m not familiar with (hopefully, for your sake).

The underside of the leaves look fine, nice bright green and healthy with no dots, no spots, nothing. Think im going to go to my local grow shop tomorrow and ask them, maybe even get something called "spidermite control" for £12, im in the UK, so no radioshack here. Think i'll give them a spray of this stuff just to make sure. Even if its not a spidermite issue this spray shouldnt do anything to my plants, and if the problem persists i know it must be something else, and will probably have the post another thread.

Anyway cheers for the help.

check under the leaves for mites or mite eggs, but it could be a fungus problem. not sure if i read that correctly but did you say you were spraying just before lights out? that can cause some fungus issues spray like within 15-20 minutes of your lights coming on, they shouldnt be hot enough yet to burn and it will evaporate of whatever the plant doesnt use. if you spray before lights off it sits on the leaves and can create problems.

The underside of the leaves look fine, but i'm going to give them a thorough inspection tomorrow as i dont want to disturb them now. Yeh i did say i was misting the plants just before lights out. The only reason i did this was because i didn't want the light to focus in on the leaves through the water on the surface of the leaves and burn them, but maybe you're right. I'll switch up my routine tomorrow and mist them just before turning the lights on and see how they like it.

lilindian said:

Think im going to go to my local grow shop tomorrow and ask them, maybe even get something called "spidermite control" for £12, im in the UK, so no radioshack here. Think i'll give them a spray of this stuff just to make sure.

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I don't know what that spray is. If it's not toxic and it's not going to hurt your plants, then give a try I guess. I know you don't have radioshack, but here's the scope that I was talking about. You might be able to find something similar where you are (or online). It really is a handy thing to have around. It's nice to know for sure if you have mites or not. And, even though you're going to spray something, I'd not count on that taking care of the problem (if it is mites) - they can be a serious pain in the ass to get rid of. More often than not one spraying of anything is not going to get rid of them.



http://www.radioshack.com/product/index.jsp?productId=2179604#

just looked at those pics again i think im leading towards spider mites cause i see web on the second and third pic on the left side of the leaf

edit: or it could be a combination of both any bug spray thats base is pyrethrum (think thats how you spell it) wont hurt your plants since its derived from a plant but i use floramite its a chemical base and tht works really wel you just gotta watch how much you apply idk if you can get that in uk tho sounds similar to what you said you wanted to try earlier.

Right, after all the replies i decided to look more closely at the underside of the leaves just now and still cannot see anything what so ever, they look perfect to me, what exactly am i meant to be looking out for? tiny white dots? Scoobster what u saw on the left of that leaf was not a web, was a bit of carpet hair or fluff or something, or dust, i dont know, but it wasn't a web, i looked for webs in my inspection and couldn't see anything of the sort.

And Leothwyn the product i'm going to buy is a blend of non toxic plant extracts designed specifically for indoor grows. Says it will completely eradicate the spider mite and its eggs without causing any problems to either the plant or you. Apparently it kills them by interfering with their mode of respiration. Planning on mixing it up and using it inside my humidifier. I'll mist the plants with the stuff just before lights on for a week. That way if its spider mites it should stop them spreading and if its mold it should stop all together as any liquid left on the leaves will be evaporated like scoobster said.

Also i will ask the grow shop if they have any cheap microscopes, want one for when the plants start budding anyway, if they make it that far.

Quick update, just to let every1 know im pretty sure it was a case of mild mold, as it hasn't spread at all in the past couple of days because i haven't been misting my plants with a humidifier.

avid and floramite are the only two things I've ever seen successfully kill spider mites and their eggs. Both should be used in veg only, so you should be good there. Other products like neem oil and even pyrithrums don't seem to work...at least in Northern California. Your pics make me think it's mites, despite you not seeing them. When I've had them I would start seeing white dots on top of the leaves like you have. Then a week later, mature spider mites on the underside. Spider mites are my arch nemesis. I've had them destroy and deplete crops before and it only seems to take a day or two for them to do so. Good luck! Hope this helps.

The spider mites I've seen always lay their eggs on top of the leaves, little white or amber cloudy balls. once they get established you'll see the eggs on top and bottom, fix it quick or they will destroy your garden quick. for mild cases I use olive oil and dish soap diluted down with water, treat it again in roughly 10 days to get the eggs that you didnt get the first treatment. Or you can get some products that will take care of it, I have some buddies that use neem oil with good results. I think the trick is to get them early in their infestation, if you wait too long it will be alot of work or you could lose your plants.

I'm betting if you took out a magnifying glass and examined all of those leaves with close scrutiny, you will see something squirm at some point.
Break out the rubbing alcohol and qtips at that point.......and sigh, no....it won't hurt your plant. The light swabbing will immediately kill what is on the surface and immediately evaporates.

dankasaurusrex said:

avid and floramite are the only two things I've ever seen successfully kill spider mites and their eggs. Both should be used in veg only, so you should be good there. Other products like neem oil and even pyrithrums don't seem to work...at least in Northern California. Your pics make me think it's mites, despite you not seeing them. When I've had them I would start seeing white dots on top of the leaves like you have. Then a week later, mature spider mites on the underside. Spider mites are my arch nemesis. I've had them destroy and deplete crops before and it only seems to take a day or two for them to do so. Good luck! Hope this helps.

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The deal with the neem and pyrithrums, they only kill adults. You have to retreat every three days for about 2 weeks to break the breeding cycle.

Aight, guess its better to safe than sorry, will buy some stuff when i go to the grow shop to get a new reflector, will update this thread in a couple days.

Cheers

are theese yellow spots just spots or are they elevated from the foliage? also what is your humidity at night?

As far as i can tell they're just spots, not elevated. Cant say for sure what the humidity is during nights, will check tomorrow, but i know its not high. Excess water was left on the surface of the leaves though when i used to mist them so im guessing that was the cause.

fungi due too moisture during night time or mites.. keep an eye open

Got a little magnifying glass today with 2 lenses, inspected leaves and still cant see any mites. Nothing under the leaves. Got the spider mite control thing today so will mist em tomorrow just to make sure.