Plants showing white spots

I am attaching a couple pictures of some spotting that has shown up on leaves on a couple White Widow ladies. They are in the 3rd week of flower. I have a couple other strains that are at the same point of flower in the room, but don’t have any spotting on their leaves. Need advice on what could be the problem with the ww strain that isn’t bothering the other strains.
Grow room kept at 77* F. Nutrients kept to the lower end of recommended doses (using Basic A&B) and some Cal-Mag.
Thanks for any advice you can give. Cheers

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Most likely pests. Captain Jack’s Dead Bug Juice. Mist top and bottom side of leaves daily before lights out until controlled. Every other day to maintain. Safe through flower.


Does it wipe off maybe white powdery mildew? (WPM)
What has the humidity been running? Lights on lights off

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Are you using an ultrasonic humidifier with tap water?

What does that cause?

Ultrasonic humidifiers aerosolize minerals in tap water and you get white mineral dust all over your grow area. It’s best to use a wicking humidifier, or if you go ultrasonic, then use distilled or RO water.


Can see a few little black specks on the top pick could be nothing.

Thanks for your reply. I’m an entomologist; no bugs. Cheers

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I have tried to rub it off with my fingers. I haven’t tried a cloth or anything else. Would you suggest there be something more aggressive tried?

I do not have a humidifier in there. Humidity is about 50% give or take.

If that was the case here, wouldn’t I have the spots on all the plants? It is just on 2 white widow plants. Blue Dream and Skywalker OG have nothing on the leaves. Cheers

Thrips thrips thrips

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I got out the magnifying glass headset that I use for checking trichomes this morning, and found spider mites on a couple leaves. @Borderryan22 was spot-on with the diagnosis!
If you see similar signs on your leaves, get a magnifying glass out.

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