Re: [compost_tea] Brassicas and vam fungi

From: <soilfoodweb_at_aol.com>
Date: Sat, 30 Oct 2004 09:44:20 EDT

There is information on brassica reducing SOME SPECIES of root-feeding
nematodes, but they then INCREASE OTHER species of root-feeding nematodes.

Reference - my husband, who is a nematolgist, at Oregon State University. He
put out a reference CD on nematode interactions in soil, available trhough
the Society of Nematology. Russ, my husband, has done quite a bit on cover crop
interactions with root-feeding nematodes.

Believe me, having been on the sidelines through all of the research, that
the interaction between any plant and the nematode community in soil is not
simple.

Temperature changes the ability of any plant to enahcne, or reduce nematode
species. Moisture level changes it. Seasonal changes influence nematicidal
ability.

And even more importantly, the species of plant determines WHICH root-feeder
may be negatively affected. NO PLANT KILLS ALL ROOT-FEEDING NEMATODES. They
may reduce certain species, but not others. You have to know which
root-feeder the plant CAN affect, and then put in the right cultivar of plant to deal
with that species of nematode.

Whereas mycorrhizal fungi on row crops are not specific for the root-feeders
they take out. I my own experience (wish I had the money to do this as a
replicated scientific study, but maybe some mycorrhizal person will get around to
it), I find mycorrhizal fungi much more effective at taking out nematode
problems than trying to find the right plant in the right conditions in the right
soil to reduce some nematode pest.

Brassica generally enhance actinobacteria in the soil, and the actinobacteria
are quite detrimental to mycorrhizal fungi. Brassica do not generaly need
mycorrhizal fungi, and in some instances (work by Mike and Edie Allen as I
recall) are harmed by mycorrhizal fungi. Brassica generally produce exudates that
do not allow colonization, and in fact may kill mycorrhizal fungi. As we look
at crops, most brassica species are never mycorrhizal where as tomato needs
mycorrhizal fungi when growing in soil low in nutrients, or high in
disease-causing fungi.

My favorite place to go looking for information about these interactions is
on Mycorrhizal Applications website, mycorrhizae.com

Elaine R. Ingham
Soil Foodweb Inc., Corvallis, Oregon
Soil Foodweb Inc., Port Jefferson, New York
Soil Foodweb Institute, Lismore Australia
Soil Foodweb Institute Cambridge, New Zealand
Laboratorios de Soil Foodweb, Culiacan, Mexico
Soil Foodweb Inc., Jerome, Idaho
Soil Foodweb Inc., South Africa







Received on Sat Oct 30 2004 - 11:25:43 EDT

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