Help me diagnose this problem please


#1

I saw this on some leaves this morning.

Thrips or mites are a possibility from comparison to online photos, but I see no evidence of bugs, just the spots. These are Northern lights autos, just beginning to flower. Any ideas?


#2

Strain; Northern Lights Auto

Soil in pots

Age from sprout?9wks
System type?na
PH of runoff or solution in reservoir?
Pt
What is strength of nutrient mix? EC, or TDS

Indoor
Light system, size?LED two HLG 260xl, two viparsoectra 450
Temps; Day, Night 69-72
Humidity; Day, Night 47-52

Ventilation system; Yes, Size two 450cfm in line fans, intake and exhaust. One 18” oscillating fan

Humidifier, De-humidifier, have used humidifier earlier
Co2; No

Alternating pH water with fox farms trio at full strength. Included cal mag for first time on Saturday may 28. Water or feed about every 3rd or 4th day. pH of both water and feed is 6-6.3.


#3

You need a jewlers loupe to see them tiny insects. They live on the underside of leaves,I have used organocide with great results. There are other products but since I’ve only used this one I can’t comment on the rest. Hope this helps


#4

So I took my little handheld microscope and spent about 20 min looking on the bottom sides of the leaves and saw no sign of mites or any bugs.


#5

It actually looks like a PH issue to me. Let’s get @Donaldj or @Countryboyjvd1971 or @garrigan65 to maybe take a peek.

How are you measuring and adjusting the PH of your water? Do you do it after adding nutes? And, what water are you using? City? R/O? Filtered?


#6

I measure pH with a digital meter to 6-6.3. I use tap water that sits uncovered for a minimum of 24hrs before pH-ing, tds=180-210. I use pH Up Down to adjust. I always adjust pH after mixing nutes. I have 3 plants that are on the same schedule and get their water and nutes from the same jugs. This is the only plant I have seen (so far) with these spots on the leaves.


#7

Have you done a slurry test on the soil to see where you are? It still looks like PH related issue and that can manifest on only one plant.

All in all your plants look good. I would like it if someone else weighed in though.


#8

I haven’t done a slurry test in a while. I just borrowed an industrial grade pH meter and I’ll try that and post the results. May be the wkend until I can get to it. I’m looking at thrip/mite treatments and will wait as long as practical before applying anything. Hopefully the problem will manifest itself and provide a more definitive diagnosis.


#9

It’s not parasites IMO. I fight spider mites and you can tell.


#10

That’s encouraging. If it’s not bugs then I’m not worried. These plants are growing so fast now, just started making fuzzies, I may need to hit them with more water.


#11

@Nod
Yellow spots
It is brought about by warm weather and rain and effect marijuana grown outdoors. It may also show up in nitrogen- deficient plants. Read this article and learn how to identify and treat yellow leaf spot.

Leaf Septoria On Marijuana Plants
In this article we will discuss:

Signs of leaf septoria
How to avoid and cure leaf septoria
Marijuana plant symptoms
Yellow leaf spot, also known as leaf septoria, are caused by Septoria cannabis and S. neocannabina. These are fungal pathogens aimed specifically at marijuana plants.

Robert Bergman
26 Comments
All, Plant Care Guides, Diseases
Leaf Septoria On Marijuana Plants
In this article we will discuss:

Signs of leaf septoria
How to avoid and cure leaf septoria
Marijuana plant symptoms
Yellow leaf spot, also known as leaf septoria, are caused by Septoria cannabis and S. neocannabina. These are fungal pathogens aimed specifically at marijuana plants.

It is brought about by warm weather and rain and effect marijuana grown outdoors. It may also show up in nitrogen- deficient plants. Read this article and learn how to identify and treat yellow leaf spot.

Signs of leaf septoria

Yellow leaf spot initially shows up on the lower leaves of your plant. These spots may vary in shade from white to a grayish brown to yellow, initially displaying little circular lesions. Once it starts to grow it starts looking like a bump and its size continues to increase.

Yellow leaf spot will harm the leaves and often times the stems of the plant, although it won’t cause the crop to die off. If for any reason this is not properly cared for it will lessen the marijuana plants yield. The affected leaves will become dry where the spot is and overtime break and produce a hole at the point where the spot started off.

Not sure if your marijuana plants suffer from a yellow leaf spot infection? Check the article Marijuana diseases for a list with pictures of all possible marijuana diseases

Back to top
How to avoid and cure leaf septoria

The most affected leaves will become totally yellow, dry out and fall off. You will want to get rid of the leaves that fell off or else you will end up with a landing turf for spores to overwinter. Basically, they will hide out until the weather warms up and then that’s when they will wreak havoc. Yellow leaf spot spores do their dirty work through traveling by water, wind and clinging on to things that pass by.

You can avoid the damage yellow leaf spot causes your plants through crop rotation. Basically, after every harvest you will pick a new location to plant. If you are not able to do this, then after harvest, completely get rid of all leftovers from the last vegetation and till the soil really good to make sure all remains are gone.

Download my free marijuana grow guide at this link for more growing tips

Get the location ready using sterilized compost and mix it well into the soil. Doing this will give the new crop plenty of nitrogen to provide a good, strong start. If you don’t have any ready compost, you can mix in blood meal, fish meal or soybean meal to the dirt that is already there.

Therefore, you will be certain to have all the necessary nitrogen for your plant. Make sure you proper disinfect any tools you used with rubbing alcohol or peroxide prior to putting them away.

One more thing you can try when beginning a new marijuana bed is adding a fungicide to the planting location prior to putting the seedlings and seeds there. You have the option to buy one of the many natural solutions pre-made (at this link here) or you can make your own.

Applying helpful bacteria, like Bacillus Pumilis or a good fungi like Trichoderma will help the soil if you don’t have any compost to use. Also, you may try spraying the site with essential oil combinations with cinnamon, coriander, neem, sesame or clove. Fine misting the soil with compost tea or even baking soda will aid in avoiding yellow leaf spot spores from making a home at your site.

Back to top
Marijuana plant symptoms
– white/grayish brown/yellow spots on leaves
– Circular lesions on lower leaves
– A small pimple looking bump
– Leaves dry and fall off

Remember to water your plants early mornings or early evening time. Never water the leaves, only the soil. By doing this, the sunlight will not burn the leaves. Again, if your plants gets infected by yellow leaf spot, it is important to always remove and completely destroy all affected leaves.

If you don’t do this, you will most likely regret it. Affected leaves still contain the problem and can come back to haunt you because yellow leaf spot easily clings on to things and travels from one destination to the next.

Remember that plants with strong genetics have less change of getting sick and are less vulnerable for pests and diseases. So make sure to buy cannabis seeds from a trusted seed bank.

Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible

Robert


#12

@garrigan65 Good morning my friend. This was the plant that I had problems with, it had a pinched airline for about a week (bad stagnant smell)and a little insect problem from bringing an outdoor plant inside.Sprayed organocide, which is an insecticide, fungicide and miticide. All new grow uninfected, very nice and green. My problem started to affect older leaves only. Should I remove all affected leaves? There’s about 10 left?


#13

YES AND DO IT A.S.A.P OK
YOU DON’T WANT THAT TO SPREAD TO YOUR OTHER PLANTS

Sorry about the caps I forgot they were on…lol


#14

Thanks buddie, will do as soon as lights come on, been spraying organocide every 3 days. Haven’t seen it spread. All other plants look fine. Once again thanks my friend.


#15

No problem glad to help and I’m happy for you that you got it before it got real bad…good job your on it…lol


#16

@garrigan65 Theses are my healthy leaves different plants,bottom pic affected leaves. This is the one with issues, after one week with a pinched line we started seeing this issue I assumed lack of oxygen. She is a revegged clone that has a ready been harvested once .


#17

Sorry @Nod for hijacking your post!:disappointed_relieved:


#18

You’re fine. Answers wherever we find them.


#19

Thanks buddy @Nod, I hope you get you issue fixed as well, @garrigan65 I also saw my roots a little more yellow compared to my others, not slimy just a tab bit of on color. She’s bouncing back fine, I will keep both updated on how’s she’s doing have a great day, I’m off to getting the day started.


#20

I have a guess as to the cause of my spotty leaves and not surprisingly the tip came from my lovely wife who, besides being lovely, is usually, most of the time, well, always right. She mentioned that she thought the affected leaves were all in the same general location, which I immediately disagreed. But on closer inspection I saw she was right. Just a few leaves lower on the plant and just on one side. I’m still keeping an eye out if the spottiness spreads, but I thing I may have doused the leaves with the last bit of nutes during my last watering and the spots are the result of my mistake.