Please help – White marks on my plants!

[Vincent]

Hi all, I am a first time grower.
I've been growing a couple of autoflowering plants outdoors for about 5 weeks now. The plants are in a soil mix and I have been using an organic fertiliser.
In the last couple of weeks white marks began appearing on the oldest leaves and seem to be spreading up quite fast. A few of the laves are now almost totally covered in these white marks and the original two leaves on both plants have now also turned yellow and look like they are dying. Please see photos.
I have sprayed the plants repeatedly with organic insecticide, but this does not seem to have made much difference.
Is this caused by insects or fungus, or something else? Please, please help! Thank you

[kingfish]

You got bugs dude. Thrips in particular. From looking at your girl, you got it bad. You can try this, but I don't know if it is going to fix it. sorry.

[Vincent]

Thank you dude, much appreciated!

[alltatup]

Hey Vince, Since you already have buds emerging, you gotta be real careful not to get any insecticide on the buds. Here's a helpful page on thrips: https://www.growweedeasy.com/cannabis-thrips

[Vincent]

Thanks for your help alltatup!

[simpleman]

It could be white powder fungis but probslby not since your plants are outside. Just throwing my thoughts into the ring.

[GreenhouseEffect]

Agreed, you got bugs, mostly thripps.
Another good thing for them is Diatomacious Earth, It's ground up fossilized sea shells, and it cut's them up cause it's so sharp, causing dehidration and death. I feel like it's OK to use early on in flowering, non toxic, but makes harsh buds if on them after harvest, since it will do the same thing to your lungs. That early in flowering though, should be gone by harvest, especially outside where rain washes it off, and the buds aren't to formed anyway's. I have smoked a little in my buds before, and am still hear. Is sold for pest control, and for mixing into livestock feed to control weevils, pretty cheap.

[GreenhouseEffect]

If you were only making edibles with a crop, I would use it up to harvest, since you can eat the stuff, and it won't hurt ya. Bad to breath in though, were a dust mask if you use it. Best way is a small fan cranked to high, aim at underside of leaves, and sprinkle the DE in front of the fan.