[compost_tea] Nematophagous fungi

From: Mike Harvey <mharvey_at_westnet.com.au>
Date: Sun, 28 Sep 2003 15:26:53 +0800

Elaine,
I had an interesting request from a friend who has been doing AACT on his f=
arm for the last year and I hope you or some one else suitably experienced =
can offer some help.
RE Nematophagous fungi.
Information in full is towards the bottom if others are interested.
"Certain fungi show great potential as biological control agents against an=
imal worm parasites" CSIRO

Chemical worm contols are showing widespread resistance problems, nematoph=
agous fungi have been shown to be effective but spread slowly in the paddoc=
k. This is a major issue in Australian Ag at the moment.

Do you have tests that can verify Nematophagus fungi in AACT or compost?

Have you had experience with the following fungi that are available in Aust=
ralia and are being sold as nematophagous fungi

 Arthrobotrys oligiospora, A. conoidus, Paecilomyces funosoroseus, P. lilac=
inus and veticillium chlamydosporium?

Would it be feasible to use an inoculation of these arganisms in an AACT ma=
chine( zero bacterial) grow them out then inoculate into fungal dominated =
compost and thus have some of these organisms in the AACT that is used on p=
astures?

This would hopefully make sure that the nematophagous fungi are in the AACT=
 that we are using on pastures.

Can we assume that Nematophagous fungi are already in the AACT if it meets =
the SFI criteria for high quality AACT?

Sorry there are so many questions any help from folks on the list will be g=
reatly appreciated!!

I have emailed the contact at CSIRO requesting more information.

CSIRO Article.

Biological Control of Worm Parasites


Certain fungi show great potential as biological control agents against ani=
mal worm parasites. This information sheet discusses the research currently=
 going on at CSIRO Livestock Industries.

With the increasing problem of worm parasites showing drench resistance, fa=
rmers are becoming more aware of the need for alternative control methods r=
ather than depend on chemical drenches that exist to date.

Certain fungi show great potential as biological control agents against ani=
mal worm parasites. Nematophagous (nematode - destroying) fungi are widespr=
ead and abound in rich agricultural soils. They catch their prey by forming=
 specialised trapping organs. These "traps" come in a number of different f=
orms such as three-dimensional adhesive networks, adhesive knobs and rings.=
 Shortly after it captures the nematode worm, the fungus penetrates and des=
troys it.

Although nematophagous fungi have been known for many years, very little wo=
rk has been done in Australia until recently. In 1990, we undertook large s=
cale screenings of fungi, focussing on fresh dung samples from grazing live=
stock. For fungi to be a practical proposition, their spores need to surviv=
e passage through the gastrointestinal tract of the animal. The fungi then =
must germinate, colonise the fresh dung and capture the infective stages of=
 the worm parasite before they contaminate the pastures. After screening ap=
proximately 2,000 dung samples, an ideal Australian fungus has been found w=
hich is able to do just this.

Rather than treating the parasitic worm in the host, as is the case with dr=
enching, biological control cuts the life cycle of the parasite in the fiel=
d, where it exists in its free-living stage. Biological control will not re=
move the worms completely from pastures, but will reduce the level of infec=
tion. When given at strategic times that correspond to the seasonal peaks i=
n infective larvae, the fungi will eliminate the rise in larval numbers tha=
t leads to production losses or parasitic disease.

On-going research into suitable deployment technology has shown that fungi =
can be successfully administered to sheep in feed supplement blocks or in i=
ntra-ruminal capsules. For field testing, the large quantities of fungal ma=
terial required can be easily grown on wheat or other grain substrates. Sca=
ling-up the production for commercial quantities is not expected to be a ma=
jor problem. Commercial development is now proceeding and it is anticipated=
 that biological control will soon be a valuable addition to nematode contr=
ol programs.



The predatory fungi physically traps nematodes using sticky threads (myceli=
a) to catch them. The fungi then penetrate the cuticles of the worms and de=
vour them.

End of article.

Regards Mike Harvey B Hort Sci

New Life Soils.

E-mail mharvey_at_westnet.com.au
www.composttea.com.au








Received on Sun Sep 28 2003 - 10:52:39 EDT

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