I believe Janis Rucksans book "Burried Treasure" gives some information on this subject, with advice for the crop rotation, and treatment regarding various fungal and other problems. There was also a thread on the scottish rock garden club forum last year discussing a black mould on the anthers of muscari and scilla in which Janis gave significant information and pictures. I have been advised by another nurseryman that control of "ink spot" on reticulata Iris is only really achieved by replanting in fresh ground every year, (though I do feel from observation of reticulata Iris, that Ink spot primarily is brought about by irregular temperatures and periods of drought during spring growth ) On Sun, Nov 6, 2011 at 12:25 AM, Rodger Whitlock <totototo@telus.net> wrote: > On 5 Nov 2011, at 9:51, Richard Haard wrote: > > > I would like to learn more about crop rotation protocols, what crops > follow > > and how many years between bulb crops. In a garden situation, or a small > > field how much 'space ' is needed separating crops, or are there trap > crops > > to use as cover cropping for nematode, virus and root rot diseases. > > Jan de Graff,......His practice was to lease land > that had never before grown lilies, and then grow a crop on them, for one > year > only. Next year, completely fresh ground. > > -- > Rodger Whitlock > Victoria, British Columbia, Canada > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >