Staffordshire,
United Kingdom 
Pistou Basil.
Hello, I have been growing pistou basil in a pot outside and recently put it in a cold frame with another basil but of the genovese variety.
While the genovese is looking healthier since being in the cold frame, the pistou one is starting to get whilted leaves on some brown stems (not the whole plant though). I'm really wondering what could cause that as it as not been flowering and it's only a young plant (sowed it last march).
23 Sep, 2011
Answers
Well it couldn't have got cold since it has been in a cold frame, I've never seen the temperature in there go below 15c.
Pistou is a variety of French Basil with small leaves and that bunches up in balls (you can get the seeds from Mr Fothergills). It is used to make "pistou" which is the original French Provençal form of pesto (which only contains olive oil, garlic and pistou basil). Although I have seen some bugs in the cold frame, I haven't seen aphids but some kinda midgets.
27 Sep, 2011
Ah, you might have fungus gnats in the compost - they seem to like basil compost particularly. Not much you can do about it, the treatment's a drop or two of a nasty chemical, not something you want to use on a food plant.
27 Sep, 2011
Thank you for your help! It is weird because my genovese basil is doing fine, these tiny midges seem to gather around my peat pots though.
28 Sep, 2011
Thank you for your help! It is weird because my genovese basil is doing fine, these tiny midges seem to gather around my peat pots though.
28 Sep, 2011
I don't know what the difference is between pistou basil and genovese, frankly - but I do know that basil plants are very prone to infestation from aphids, etc., and are extremely sensitive to cool temperatures, preferring higher ones. Perhaps it got too cold at some point.
26 Sep, 2011