Torula yeast for oilive fly traps

 I had similar ambitions for organic olive fly prevention some time ago and if I remember torula yeast is produced from waste wood and is added to pet foods to boost the protein content as it is cheap. It seems readily available in the States but not here. I really think ordinary yeast tablets or powder produced for the vitamin-conscious and sold in whole food and additive chain stores would work just as well and if bought in the bigger packs, nearly as cheap. Don't forget however that the traps must be cleaned out and refilled on a weekly basis!