nematodes and cover crops was Edible Bulbs - Allium

Richard Haard
Sun, 06 Nov 2011 16:23:14 PST

Managing cover crops profitably can be downloaded free . Has been a source of info for my program.…

We do not bring in any live plant material into our farm, all plants are sourced from seed propagation. Been growing Camas and lilies for 20 years in some parts of our fields and have not seen disease yet, ahem - knock on wood-. Nematodes are not an issue - yet - but keeping soil healthy is big concern.  We summer, and or winter cover crop with sunflower,vetch, buckwheat, rye and sometimes mustard on 2 year cropping cycle. Improvement in soil OM and weed regime has been noticeable. Disease - we have no data but need to maintain best practices. 


Thanks for information about marigold

clip from page 26

Using brassicas and many grasses as cover
crops can help you manage nematodes. Cover
crops with documented nematicidal properties
against at least one nematode species include
sorghum-sudangrass hybrids (Sorghum bicolor X
S. bicolor var. sudanese ),marigold (Tagetes patula ),
hairy indigo (Indigofera hirsuta ), showy crotalaria
(Crotolaria spectabilis ), sunn hemp
(Crotalaria juncea ), velvetbean (Mucuna
deeringiana ),rapeseed (Brassica rapa ),mustards
and radish (Raphanus satiuus ).
You must match specific cover crop species
with the particular nematode pest species, then
manage it correctly. For example, cereal rye
residue left on the surface or incorporated to a
 depth of several inches suppressed Columbia
lance nematodes in North Carolina cotton fields
better than if the cover was buried more deeply
by moldboard plowing. Associated greenhouse
tests in the study showed that incorporated rye
was effective against root-knot, reniform and stubby
root nematodes, as well (20).
Malt barley,corn,radishes andmustard sometimes
worked aswell as the standard nematicide to control
sugar beet nematode in Wyoming sugar beets, a
1994 study showed. Increased production more
than offset the cover crop cost, and lamb grazing of
the brassicas increased profit without diminishing
nematode suppression. The success is conditional
upon a limited nematode density. The cover crop
treatment was effective only if there were fewer
than 10 eggs or juveniles per cubic centimeter of
soil. A moderate sugar beet nematode level was
reduced 54 to 75 percent in about 11weeks,increasing
yield by nearly 4 tons per acre (231).
On Nov 6, 2011, at 3:42 PM, J. Agoston wrote:

> 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
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