THCFarmer.com
121,288 Members Log In Register
Log In Register

Fungus gnats cause yellowing leaves?

  • Thread starter Thread starter Green Giant
  • Start date Start date
  • Tagged users Tagged users None

Fungus gnats cause yellowing leaves?

Green Giant 21 Replies 9,428 Views
Page 1 of 2 · Replies 1–20 of 22
Green Giant

Green Giant

Posts
284
Reactions
140
Joined
Sep 27, 2011
Points
43
#1
Could someone tell me if having fungus gnats could cause yellowing leaves?

I have some ladies with yellowing leaves then eventually dying leaves. The leaves are also kind of spongy wet feeling.

I have changed nothing in my rooms or my feed schedule.
 
#2
Sounds like it could possibly be root aphids.Phantom deficencies and fliers are common with them
 
#3
Wouldn't I be able to un-pot and find some in the root mass if that is what's causing this? I have and found nothing.
 
#4
Look really close those fuckers are really small.Could be some thing else thats just what came to mind from the description just trying to help.Good luck
 
#7
Green Giant said:
I think I let the pots dry out enough, I water every third day. I may kick it up to every second day.

What makes you think over watering?
Click to expand...

Generally it is over watering if the plants droop a little and the leaves start turning yellow from the bottom up. If it's sporatic yellowing up and down the plant, and the leaves get spotty as well, I woudl say RA, or possibly the plants got too dry and the nutes burned them a bit.

also as the plant grows larger and the lower inside leaves are not getting light anymore, they will naturally yellow up and die.
 
#8
Yellow sticky traps are your friend here, just keep them away from arms and such. Pix would also be helpful, but sticky traps would tell you with a quickness whether or not, and what it may be.
 
#9
Cap. I would say its a general all over yellow not just spots. It starts at about week 4-5 in bloom, and all the way to finish. I really notice how yellow they are when I bring them out of the bloom room to cut. My last batch of Chemdog #4 came out With some of the sugar leaves in the bud dry and dead. Made bag appeal look like crap!

Seamaiden said:
Yellow sticky traps are your friend here, just keep them away from arms and such. Pix would also be helpful, but sticky traps would tell you with a quickness whether or not, and what it may be.
Click to expand...

I have sticky traps and I know I have fungus gnats. Just trying to figure this all out!
 
#10
Green Giant said:
Cap. I would say its a general all over yellow not just spots. It starts at about week 4-5 in bloom, and all the way to finish. I really notice how yellow they are when I bring them out of the bloom room to cut. My last batch of chem 4 came out With some of the sugar leaves in the bud dry and dead. Made bag appeal look like crap!



I have sticky traps and I know I have fungus gnats. Just trying to figure this all out!
Click to expand...

temperature?
 
#12
Inspect the roots and if you find aphids that may be the problem. Your temp swings are also a little much. 20 degree swings are no bueno. 10 or less is best. Keeping the temps the same day and night will reduce stretch as well...

87 is a little on the high side, unless you are running CO2 then that is fine.
 
#13
The high RH plays into Cap's over-watering theory as well. When the relative humidity gets too high the plant's transpiration rates will slow and consequently so will the rate at which your plant will uptake water/nutes from the medium. Also higher temp and RH create an environment that is more conducive for pests.


Green Giant said:
Cap. I would say its a general all over yellow not just spots. It starts at about week 4-5 in bloom, and all the way to finish.
Click to expand...
This is in reference to root aphids. "In some cases the plant is able to maintain a reasonable level of resistance to the pest and continue to thrive, though with reduced vigor. The damaged roots often prevent the plants from taking up adequate levels of magnesium and iron. As a result, consummate growers who grow very healthy plants and maintain very clean environments may inexplicably experience a mysterious deficiency of some sort around day 21 to 30 of flower."

Cited from:
 
#14
im having a little trouble with my veg, 4 weeks in and the roots were interwound cos i had 2 plants in one pot for a little too long.... . now ive seperated them into single big pots . growth has slowed down and leaves are little droppy not chasing the light,, also a little yellow on the bottom half of the plant.... any help is welcome.....
 
#15
dan jones said:
im having a little trouble with my veg, 4 weeks in and the roots were interwound cos i had 2 plants in one pot for a little too long.... . now ive seperated them into single big pots . growth has slowed down and leaves are little droppy not chasing the light,, also a little yellow on the bottom half of the plant.... any help is welcome.....
Click to expand...
if you just separated and repotted them they should recover just fine, just give them a little time.

...water sparingly until you see the droopyness stop, going up to a much bigger pot and watering in heavy leaves the medium too wet for too long and you can end up with overwatering symptoms so go easy until you start to see new growth.

peace, bozo
 
#16
If u are seeing flyers and ur leaves are dieing and drying off its possible u have flying aphids look under your fan leafs thats where they lay there eggs that hatch into larvae that feed on the oils in ur leafs.
 
#17
fungus gnats! I just got rid if these little pest, Went to my local grow store and talked to one of the guys there and he gave be a baggie with some homemade powder that you mix with the water and it kills them off. It took a little over 2 wks and the shit worked, I went back to ask what was in it and he would not tell me for some reason. Said a customer makes it for him to sell. It looked like a dark orange substance? Dont know what it is and I dont care I just know it works, and for the 6 buck I paid it was well worth it.
 
#18
Canappa said:
fungus gnats! I just got rid if these little pest, Went to my local grow store and talked to one of the guys there and he gave be a baggie with some homemade powder that you mix with the water and it kills them off. It took a little over 2 wks and the shit worked, I went back to ask what was in it and he would not tell me for some reason. Said a customer makes it for him to sell. It looked like a dark orange substance? Dont know what it is and I dont care I just know it works, and for the 6 buck I paid it was well worth it.
Click to expand...
if fungus gnats are a recurring problem you can put a layer of hydroton or grorocks or something like that, hell, even glass marbles would work, the point is that fungus gnats are only a problem as larvae, the flyers are only the egg layers, ...it's the larvae that eat the roots as i understand it but they live in the top layer of the soil and if you cover that with an unfriendly substance they can't recover, most especially if you also use sticky traps, use these two strategies and fungus gnats will never be anything but a nuisance going forward.

fungus gnats are EASY!

peace, bozo
 
#19
justanotherbozo said:
if you just separated and repotted them they should recover just fine, just give them a little time.

...water sparingly until you see the droopyness stop, going up to a much bigger pot and watering in heavy leaves the medium too wet for too long and you can end up with overwatering symptoms so go easy until you start to see new growth.

peace, bozo
Click to expand...
thanks bozo.. ill keep and eye on them now and not over water.. cheers
 
#20
Got some gnats in my last 5 or 6 bags of soil I picked up. Roots organic original. Put up some yellow sticky traps and got a bunch of adults caught on them. Was looking through info on how to kill the larvae as I don't want them eating my roots. I do use caps tea mix once a week....i may just not dilute the tea as much and see if that works.

Also read you can use one part pure 3% hydrogen peroxide with four parts water and that will kill them in the soil. Has anyone had any experience with this?
 
Last edited:
Page 1 of 2 · Replies 1–20 of 22
Back
Top Bottom