Could it be Mold?

[medjool]

I have my plants in a greenhouse. Two have already wilted and died from some strange affliction. I am worried that it is spreading to the other plants. The plants were germinated in early January and spent two months in an indoor grow room before being moved into the greenhouse in mid-March.

I have applied neem twice since March, and one application of BT. Also, since there were slug bites on the leaves, I applied Iron Phosphate (Sluggo) in the pots. That got rid of the slugs. Now there is something that could be a mold attacking the stalks of the plants. The pictures attached show the damage. One plant, approximately 5 feet tall has a gray area on the main stem about 10 inches from the top. All the leaves above this gray area are wilted and look like they are dying. You can see the wilted leaves in the first picture, and the gray area on the stem in the second picture.

Anybody got any idea what this is? Other plants have some similar graying and mushiness at the base of the fan leaves where they hang on the stem.

The third picture shows another affliction. Gray patches at thetips of the leaves. This is spreading throughout the plants. Is it the same mold?














Medjool

 

[HeadyPete]

Do you have good air circulation in the green house? A strong oscillating fan is a must.

Some in focus pix would help see the actual symptoms. That last pic looks like a nute lockout, I doubt it is related to the other problem that is killing your plants.

A good safe preventative for slugs is to encircle your plants with copper foil or thick wire so that the slugs must crawl over the copper to reach the plants. When they touch the copper their slimy bodies generate an electrical zap that keeps them away from the copper, and your plants. I would use a control like that over adding something to my plants.

 

[bighogg]

that's a "pythium wilt" or a similar pathogen.

what are you growing in? method?

 

[HeadyPete]

Please fill out this form:


SOIL:

How long has this problem been going on?
What STRAIN are you growing?
What was the establishing technique? (seed or clone?)
What is the age of your plants?
How Tall are the plants?
What PHASE (seedling, vegetative or flower) are the plants in?
What Technique are you using? (SOG, SCROG etc)
What size pots are you using? (Include how many subjects to pot)
What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?)
What Nutrient's are you using?How much of each with how much water? How Often? *Knowing the brand is very helpful*
What is the TDS/EC/PPM of your nutrients used?
What is the pH of the "RUN-OFF"?
What method of pH test was administered? Using Strips? pH pen?
How often are you watering?
When was your last feeding and how often are you feeding?
What size bulb are you using?
What is the distance to the canopy?
What is your RH Factor? (Relative Humidity)
What is the canopy temperature?
What is the Day/Night Temp? (Include fluctuation range)
What is the current Air Flow? (cfm etc.)
Is the fan blowing directly at plants?
Is the grow substrate constantly wet or moist?
Is your water HARD or SOFT?
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
Has plant been recently pruned, cloned or pinched?
Have any pest chemicals been used? If so what and when?
Are plant's infected with pest's?

 

[medjool]

The plants are growing in 20 gal pots filled with soil enriched with compost. There is a non-oscillating fan blowing the length of the greenhouse which is 12x9 feet. The top vents are open. For the last 10 days or so there has been high humidity--approx 80%, and temperatures have ranged from 50 at night to 70 in the day. Did I mention that I have a No Pest Strip hanging in the center of the greenhouse, and I haven't seen any evidence of spider mites. I did feed the plants around mid-May once with Bat Guano, and once with Seabird guano. After I did that, some of the plants developed orange spots about 2mm wide around some of the large fan leaf centers. The plants may be a little crowded as well

By around mid-June, I am planning to move most of them back into the grow room and put them on a 12/12 lighting schedule to get them flowering.

Thanks for the comments. I'll be looking up pythium wilt. I thought it might be gray mold--but that is something that usually hits them in September--or the fall. However the weather here has been very much like September for the last two weeks in May and will likely continue that way through June. I know that gray mold is very temperature sensitive, and only grows when the temperature is between 60 and 70 degrees which it has been during much of the last few days. However, i thought gray mold only attacks flowers. Whatever is doing this is attacking the stems of the plants--and in the places where the branches join the main stem. As for nute burn--I haven't fed them for at least two weeks now. This must be from the last feeding.

This is the first time I am doing this myself. My wife did this for many years until she died last November. This is a real learning experience for me, and I really do appreciate the comments and help I get here at ICMag. You guys/gals are really great--and I need you because I can't ask too many questions at the local nursery about my specific plants. Hehe. I'll try to get higher quality fotos posted.

Medjool

 

[bighogg]

my experience tells me you are either over watering or that pot size is too big for your plant. the extra moisture encourages pathogen growth and thus the pythium wilt.

20 gallons IS big, but if the plants are drinking it fast enuf then it won't matter.

cut back on watering immediately.

 

[stinkyattic]

For the last 10 days or so there has been high humidity--approx 80%, and temperatures have ranged from 50 at night to 70 in the day. l

Perfect conditions for indoor dewfall. Which in turn means perfect conditions for fungal pathogens.

If you do not already have a tarp or other vapor barrier covering your greenhouse floor, add one. And continue researching fungi. You may end up needing a sulfur burner in there. Neem is fantastic for PM, but falls short on molds and wilts that attack the stem and root system. Bacillus subtilis is another route to take, trade name 'Serenade'.

 

[medjool]

I think I solved the problem with a fan and leaving the vents open 24/7. A slight breeze seems to keep the plants from succumbing to whatever was making them wilt. And I think the gray leaf tips were really nute burn. I've learned my lesson about feeding plants--best to do it sparingly.


Medjool