Some help identifying spotting late in flower

[jrizzle385]

Hello all. I hate for my first post to be in this section but to be honest up to this point I haven't needed any help at all. This forum is loaded with information!

That said, I'm running into my first hiccup. I have two small plants claimed to be skunk x afghani that I received from a friend who was over his plant limit (they decided to spontaneously go into flower after a power outage in the veg tent). They have been doing wonderfully, but here at about week 5 of flower I'm seeing definite signs of deficiency.

Medium: coco coir
Nutes: Lucas formula + calmag + peroxide (fed every watering)
Light: 100w HPS in micro cabinet, week 5 of 12/12
Temp: 80-82 at plant canopy
Ventilation: TONS! (overkill 95cfm blower in tiny cabinet)

I have my thoughts as to what it could be but I thought I'd ask for opinions before I go and change anything. This is a fast finishing strain and likely only needs another 2 weeks absolute max before the chop.

Pics...

The problem is manifesting itself on essentially the whole plant. Some of the lower more shaded leaves on smaller budsites appear to be the least affected.


Thanks in advance for all the help! If I've left out anything pertinent information please fire away.


EDIT: Oh....I forgot to mention pH. I use aged tap water. After nutrients are added pH ends up in the 5-5.5 range. No adjustments. I no longer check pH and I don't over water so I've never checked pH of runoff water.

 

[RubeGoldberg]

PH is too low, you wanna be higher in the 5.8-6.0 range

Also its a good idea to keep an eye on it regardless, your tapwater can change quite a bit depending on your local water table, weather patterns etc


Can you post the PH of your Run-Off? being around 5.5 MIGHT be okay as a starting point if your runoff is coming out a lot higher.

The leaves are also a bit speckled in some places, have you looked hard for pests around?

 

[intotheunknown]

^^ yeah i agree.

that first picture looks somewhat like spider mite damage. the pic is kinda blurry to me. flip those leaves over and inspect for mites.

 

[jrizzle385]

Thanks for the responses. I haven't seen any signs of pests at all and I did give the leaves a good look over including the underside. I have a small amount of fungus gnats hanging around but those are inevitable.

I'll check the runoff pH tomorrow after a normal full strength watering and update.

 

[jrizzle385]

I tested the pH again today and I'm reading 5.5. Beginning to doubt it being pH related. All other plants are fed the same nutrient solution and none are showing these signs. I'm thinking it must be a salt buildup in the medium. I didn't water these particular plants today so I don't have runoff pH. They'll get a standard feed tomorrow and I'll check runoff pH then.

 

[Toes.]

that first picture looks somewhat like spider mite damage.

+1 for mites

I haven't seen any sign of pests at all.

that's what those little white dots on your leaves are.

Aphids can make similar spots, but are a lot easier to see with the naked eye. They also like to hang out on the terminal ends of the new growth.

Mites are hard to see without a magnifying instrument. Most indoor gardening shops carry pocket microscopes for pest identification. yep, they're not just so you can check your trichs.

They could've come with the plant since you have no spots on your other plants.

I would flush with distilled water... before anything else.

Just to help out... I had a 6 footer kush strain with those dots all over a few of the lower fan leaves, I looked and looked for pest and didn't see anything. At first I thought it was wind burn and moved the fans... the spots didn't clear up they just kept traveling up the plant. I didn't notice the bastards had made camp in a nearby eggplant. the eggplant was trashed, webs all over the place, the harder to see leaves were almost white from those fuckers eating all my chlorophyll, shoot... I would've never noticed until they attacked the Ganj, it's not like I inspect my eggplants everyday. after a good dowsing with pyrethrins and neem on the 1-3-7 then I revamped the whole greenhouse because, mites move in but they don't move out.

fungus gnats explain the necro tips you have there. their larvae are eating your roots, which presents like most all root damage... moisture stress... like, over-feeding, hot containers, not enough water, too much water, etc... It's a beautiful relationship the larvae and adult have there. the larvae eat the roots which kills the the leaves, then the adults eat the dead leaves. standard gnat control should get those little bastards.

you might get lucky and those perfectly round white dots are just wind burn. I'll think positive thoughts for you.

One more thing... a 5.5 pH in hydro is to combat root rot right, so you might not need the peroxide in EVERY watering if your pH is so low... 5.0 is just plain TOO low. I grow in peat moss and my ladies love a 6.5... any lower in my house and the N, Ca, and Mg get locked out.

did you check your root mass for the dreaded RA? they also present like fungus gnat larvae.

 

[jrizzle385]

Allright. Gave them a thorough inspection today and I'm still not seeing mites. I flushed both plants through a few times with pH 6.0 water and back in the cab they went. I guess I'm playing the waiting game now.

In any case the paranoia of spider mites has me wanting to get a hold of something to prevent them. I'll take a look at the local shop.

 

[jrizzle385]

Everything I'm reading has me leaning towards root aphids now

The phantom magnesium lockout seems to be accompanied by a few winged creatures that look a bit bigger than my usual fungus gnats. I haven't inspected the roots but I'm expecting the worst. For now, I'm going to start with insecticidal soap soaks and hope I can salvage these plants this close to harvest. If the condition doesn't improve within the weak they're getting chopped before they die off completely.

I assume the likelihood of the bugs being spread to other flowering plants and my mother plants is pretty much certain. I'm going to bite the bullet and get a hold of some merit 75. I assume the wettable powder is what most are using?

 

[jrizzle385]

These nasty fuckers need to go! Seems I've got about the worst pest you could have. I grow perpetual so by this point it's inevitable that I need to do a thorough treatment to iradicate them. I'd like to document my course of action here in hopes that it may help someone down the line in my shoes. I'm not going easy on them!!!

I've decided it's at least worth the effort to save my flowering plants. I feel they are too close to harvest to treat with imidacloprid. I decided to go with spectracide triazicide to treat the flowering plants as it's safe to use up to 7-21 days for food crops. I fully submerged the pots in a solution of ~15ml/gallon for about 10 minutes each. I allowed them to drain then gave a heavy foliar spray with natria insecticidal soap to fully hit the plant. I'll give the root mass another soak in 3-5 days with the insecticidal soap as that can be used up to the day of harvest. Even if things improve I will stick with this regimen.

For the clones just moved into flower I simply gave the insecticidal soap spray today. I think I have enough time on these to apply imidacloprid since they were just moved into the flowering cabinet. I'm going to wipe out all the other clones in the veg cabinets. My mother plants and the male I'm saving for a seed run will get imid treatments as well.

 

[Toes.]

dude try Spinosad.

 

[RetroGrow]

Root aphids were my guess.
They are difficult to deal with this late, however, you can use Botanigard ES in flower. Some people have had good results from that.

 

[jumanji2]

Yea i was going to suggest a Mag def. Tell your boy he owes u a couple man, he kinda jagged it for ya there. Hope everything works out.

 

[Crush]

Seems to be a mineral problem as it's effecting the whole plant at once.. not just new growth or lower growth etc.


Mineral problems point to PH problems. Are your other plants clones of this one?

 

[jrizzle385]

Yea i was going to suggest a Mag def. Tell your boy he owes u a couple man, he kinda jagged it for ya there. Hope everything works out.

"no such thing as a free lunch" haha

Root aphids were my guess.
They are difficult to deal with this late, however, you can use Botanigard ES in flower. Some people have had good results from that.

I've heard this as well but I wasn't able to find any locally and didn't have the time to wait with the way things are progressing.

I was also recommended to try azamax. It's also stated to be safe up until harvest. But it's $70 a bottle and I wasn't able to find much info on treating root aphids with it.

So far I don't see any sign of them in the plants. The two girls most heavily effected are still drinking quite a bit so my hope is the root mass is healthy enough to allow them to finish.