Mustard as a green manure is suppose to help control Nematodes Sow mustard seed as a green manure. When crops have been cleared broadcast mustard seed over the surface, rake it in, water it, grow it to 45 centimetres high and then dig it in. If the soil is moist, the mustard will decompose and release chemicals known as 'isothiocyanates.' This is the chemical that gives mustard its hot flavour and it's that chemical that fumigates the soil and helps control nematodes. http://abc.net.au/gardening/stories/… http://www.nematode-control.com/e_variety.htm _____________________________________ From: J. Agoston <agoston.janos123@gmail.com> Subject: [pbs] nematodes was Edible Bulbs - Allium Date: November 6, 2011 6:42:54 PM EST To: Pacific Bulb Society <pbs@lists.ibiblio.org> Reply-To: Pacific Bulb Society <pbs@lists.ibiblio.org> I have never seen in Holland to rotate the fields between crops. The prices of field is so high there that they would not be able to afford it, they cannot even buy field there, just rent it for 99 years, and relatives cannot inherit fileds, as I know. Most nematodes like Meloidogyne hapla and Ditilenchus dipsaci are polyphagous. They can live on other plants as bulbs or root crops, they also survive on weeds. If you ever have a nematode problem you cannot eliminate it. We have nematicids, but they are not 100% effective as methyl-bromide was, or steaming the soil. But with those technologies, still nematodes survived in lower soil levels. Rule of thumb is as long as a root can penetrate the soil the nematodes will go down there. So it is a bit like the case with viruses. I have rented a field this year, and there was nothing just weeds for 7 years, before that potato was there. Upon harvest I noticed nematodes in the crop I sown from seed. Just think about it, why did the dutch swithched to isolated production of vegetables and cutflowers? They had a seroius nematode infestation in their greenhouses, so seroius that they couldn't control it with chemicals anymore. Sowing Tagetes is a good biological way to reduce the nematodes, but you cannot eliminate them. You have to keep Tagetes on the field for at least 2 months, the longer the better. It is used mainly for the control of Meloidogyne. The eggs will open if the Tagetes roots get near to them. The invasional larvae (J2 - juveline nematodes) will enter the roots at their tips, but this plant is not their host, so they will die within days. If ther in nothing in the soil, the eggs wil lay there waiting for a host plant's root for years. There was an experiment with Globodera rostochiensis. After 8 years of keeping the soil free from host plants my collegues still have foung viable cysts. Janos, Hungary