Need expert help

I'm really not sure what this is, but I think it's some sort of fungus or mould. It's already spread onto the main stem from one of the side branches. Does anyone know what this is, and what I can do to get rid of it (hopefully without removing the whole branch)?

IDK what the hell that is, but if its any kind of mold or fungus just spray some H202 on it. That'll kill any mold and most fungus. Looks to me like something (chemical ferts maybe) got spilled on it. Looks outdoors though so could be anything. Good luck!

Thanks for the reply. I only use organics so it can't be from spilling ferts. I'm positive it's mould. I've done a bit more digging and it seems h2o2 or baking soda (?) works. I don't know what ratio I should use of either though, anyone that can help will get +rep.

it does look like fungus,or something has laid something deep within the stalk and its eating in from the inside(some kind of larva?)

It looks like stem rot. The cause is yet to be determined.

Dont use the baking soda its too alkaline. Use the peroxide. Even full strength it will not harm the plant. But 2 parts water to 1 part H202 will do the trick too.
Ed Rosenthal says >
"Hydrogen peroxide is essentially water with an oxygen atom attached to each molecule. Its chemical formula is H2O2. The second oxygen atom is ready to jump from the peroxide to other molecules and to oxidize them. It readily jumps onto mold spores and bacteria and destroys them by burning them up. Peroxide is sold in different strengths. Indoor garden shops sometimes sell 10% peroxide, but drug stores usually sell the 3% strength.
One part of 3% hydrogen peroxide can be combined with two parts water, or one part 10% solution is combined with nine parts water, to make a 1% solution. This solution should be used for cuttings for the first week. Nutrient and amendments can be added to this mix. It can also be used in the sprayer if you mist the plants. It is a sterilizing agent, so your cuttings are much less likely to suffer infection."
Good luck!

How old is the plant if the plant has been around for some time the the green stems can get a more woody coating.But i would play it safe and out the effected brance or brances.I know that this will effect the yeild but if this is some kind of mould it could kill the whole plant.But on the other hand if the foilage is still in good shape then let it be.

The plant was started in february-march this year, and has been outdoors since. The base of the stem has gone woody, but the mould or whatever it is is halfway up the plant. The rest of the stems are green/purple- and it's not woody, the affected part is grey. I'll go with the h2o2 then. Thanks for the help everyone.

Watch the plant closely, that shit can spread rapidly. It is difficult to do but sometimes the best solution is to cut out the infected area. I have used a razor blade to cut out the affected area, apply H202 and seal with a tree pruning compound. Whatever works to keep her healthy until harvest... Good luck.