Gnats and yellow and pale green leaves.

Can gnats cause leaves to yellow?

Not sure but I know root aphids can. Adult aphids looks very similar to gnats. Try to catch one without smahin it and look at it with mag glass and compare to pics online.

Monterey garden spray (spinosad) works great for mites, gnats, aphids. Not harmful to humans but detroys bugs. Can even be used into late flower but wiuldnt recommend it cuz it smells pretty bad.

Get sticky strips and cut a piece and put it on top of medium(replace when 3/4 full) and hang a full one above plants.No the gnats wont cause yellowing thats another issue.

hello to answer your question yes fungus gnats can cause yellow leaves if they get bad enough 8( they will eat the fine hairs on your roots8( and usually nitrogen is the first thing to show 8( if your in soil wait till your plants are dry dry till you water for several weeks 8( if there really bad use a soil soak treatment you need to kill the larva they will go away after a week if the larva die. never seen them in hydro but i use food grade peroxide and they hate that so they leave it alone if in soil don't use h2o2 it will kill all bacteria that make your nutes . treatments iv'e tried are go gnats it works ok for soil after like 2-3 treatments hate the smell though 8( gh azamax works ok to after a few treatments 8( but there's no substitute for dry soil .the larva only live in the top inch or two so they dry out and die hope that helps and if you have cash sticky strips are helpful for adult gnats and for knowing what insects are in your garden good luck if your gnat problem isn't bad i would guess ph problems 8( nute def is less common than people think check your run off ph if in soil calibrate your meter if in hydro happy growing