It's been a long time since I originally posted in this thread. I have spent the past couple nights reading the entire thing.
2 years ago I received a cut from Canada that brought "duds" to my garden. I had GG4 a year before this and many other cuts and NEVER had a problem until this shitty cut made it's way in. I had never grown this particular strain, and it was a real bitch to root and grew like shit. I finally got a tester in to a bed. Well, that plant was a dud and in that same bed there were 7 other plants. Two of them had branches that dudded. Figured it was some weird random shit. Like an idiot I took soil from those beds and potted up other plants, that eventually found their way to other beds... and pretty soon it was a plant here, a plant there, a half a bed here, a full bed there...
I think it is important to note that a lot of people in this thread think they have duds, but they do not.
Dud symptoms are:
-Brittle stems (easiest way to identify-Shorter node spacing
-smaller fan leaves
-lateral branching
-Terrible trich production on fluffier, hairier buds
Variegation is not really a symptom of "dud", neither is leaf twisting, or crispy leaves, or nutrient deficiencies...
In my opinion, the culprit is stem nematodes. I successfully identified them in my garden thanks to people like
@whatthe215, except I could not find them with his method. I instead used a pair of vice grips to crush a section of trunk while dripping a little water over the crushed part and on to a slide. This is a much better way to find them.
Here is a video I made of them:
After identifying them, I purchased a professional steamer (didn't work) and ultimately a large water heater to soak the soil with 160* water between runs (worked like a charm). I also added chitosan at 1/2 gram per gallon weekly, and lots of foliar and root pack.
Hot water fucks them up bigtime. I no longer have dud plants.
High temps in the room will also cause dudded flowers, especially on OG's. I think that if you see dudded flowers, try dropping temps to 71-74 for the whole grow and see if the strain still duds out... Dudded flowers are not the same as dudded plants. Dudded plants can be saved if you always take a healthy top for a cut, and continue to cull duds (you will become an expert at identifying them) and take healthy tops for a good long while. IME the nematodes have a hard time getting all the way to the tops. It really is a race against time though. You have to pull a cut before the plant is a full blown dud. Once it is full blown just toss it. I have cloned out of dudded FPOG, GG4, white bubba, Jew Gold, Wifi 43... so it is possible.
I now have a dud free operation and have had several successful runs of nortorious dudders (gg4, Jew Gold, etc). Be diligent and you can beat it. I have had it all, and not once have I scrapped a whole grow. Everything can be beaten, and kept away with a good IPM strategy.
Peace out and happy growing,
Cap