Ive never seen this! Can anyone help?

[alliekat7861]

hey there
so i have a modest outdoor going right now. I have about 35 plants and around a third of them are getting there strange yellow spots on them. Ive never seen them before. Some background on the plants, they were started in April they're a mix of genetics strains and species. They're in 15 gal pots we use amended soil and your usual liquid nuits like a base a and b, cal meg, sillica stuff like that. the only thing I think it could be in that realm is I spray the plants with is this mammoth bug spray that's only used if the bugs get bad but I've been doing that and only now is this happening and its only on a third of the plants. all the plants are fed the same way. I'm in upstate NY also. So, it's this yellow spotting on some fan leaves otherwise, they plants are doing great! I've attached some pictures. any advice would be greatly appreciated. Love this site!
thank you =)

 

[Novaracer69]

Get some close ups of underneath the leafs. That's usually where you will find the culprit. If it's a critter and to me that's what it looks like. A couple of questions is it from top to bottom and is it only on new or older growth?

 

[TheDankest]

Get some close ups of underneath the leafs. That's usually where you will find the culprit. If it's a critter and to me that's what it looks like. A couple of questions is it from top to bottom and is it only on new or older growth?

I'm thinking pests as well, as in some of the photos you can also see some small holes chewed in the leaves. If you find some critters in there, look into some Neem Oil. I only have one cannabis grow under my belt but neem oil has served me well for various pests on my other plants, and it's also all natural.

 

[Beachbumm]

hey there
so i have a modest outdoor going right now. I have about 35 plants and around a third of them are getting there strange yellow spots on them. Ive never seen them before. Some background on the plants, they were started in April they're a mix of genetics strains and species. They're in 15 gal pots we use amended soil and your usual liquid nuits like a base a and b, cal meg, sillica stuff like that. the only thing I think it could be in that realm is I spray the plants with is this mammoth bug spray that's only used if the bugs get bad but I've been doing that and only now is this happening and its only on a third of the plants. all the plants are fed the same way. I'm in upstate NY also. So, it's this yellow spotting on some fan leaves otherwise, they plants are doing great! I've attached some pictures. any advice would be greatly appreciated. Love this site!
thank you =)

It's septoria, aka. yellow leaf spot.