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INTRODUCTION The glucosinolate-myrosinase system,
typical of the Brassicaceae family, may provide a
natural alternative for controlling soil borne
pathogens due to the high biocidal activity of
its derivative products (mainly isothiocyanates
and nitriles). The presence in all Brassicaceae
plant organs of good glucosinolate (GL) amounts,
and of the enzyme myrosinase (MYR) that catalyses
their hydrolysis, has suggested the practical
possibility of amending soil with biocidal
compounds by the cultivation and green manure of
selected species of this family (biofumigation)
(Fig. 1). The application of this technique even
at full field level has given in these last years
interesting results, with clear advantages for
the following crop yield if compared with a not
treated soil and/or a conventional green manure.
OBJECTIVE Evaluation of biocidal dried pellets
obtained from some Brassicaceae as organic
treatments in addition or in alternative to
biocidal green manure.
Fig. 1 Biocidal plants chopping up
RESULTS The first aim was to limit, during drying
up, GLs losses (Tab. 1) and to maintain active
the endogenous MYR that catalyses their
hydrolysis. Among several biocidal selection,
Cleome hassleriana (Fig. 2) showed lower GLs
losses during dehydration together a good
adaptability to spring sowing, and a sufficient
biomass yield (reported in Fig. 2)
Height 80 100 cm
Fig. 3
Plant Biomass Fresh 30 3.8 t ha -1 Dry 5.9
1.0 t ha -1
Fig. 2 Cleome hassleriana
Tab. 1 Plant GLs content after dehydration

• Cleome hassleriana ISCI 2 dried plants show
• a high content of glucocapparin
  (methyl-glucosinolate) (Tab. 1) and a MYR amount
  sufficient to catalyse glucosinolate hydrolysis,
  with production of Methyl-isothiocyanate, an
  active ingredient of some commercial chemical
  fumigants (Fig. 4). In this way, dried plants are
  able to produce the biocidal compounds when
  watered (Fig. 3).
• a high fungitoxic activity on Pythium irregulare
  and Rhizoctonia solani, two of the main target of
  biofumigation. The addition of exogenous MYR in
  the water-dried plant mixture did not determined
  significantly different fungitoxic activity (Tab.
  2)
• the possibility to be prepared as pellets for an
  easier and practical distribution (Fig.4)
• no limitation for organic farming

Methyl-isothiocyanate
OZT Cleomin
Epi-progoitrin nitrile
VOT Epi-progoitrin

Fig. 3 Hydrolysis products of dried plants
after water addition. Exogenous epi-Progoitrin
was added to the mixture to confirm the presence
of MYR activity
CONCLUSIONS These results on dried plants open
interesting applicative perspectives in addition
or in alternative to biocidal green manure. The
phase out of Methyl Bromide (2005) will cause a
growing interest for ecologically compatible
alternatives and this means that this technique
could be applied not only in organic farming, but
even in conventional agriculture.
Fig. 5 - Dry plants effect, in vitro, on
Phytium and Rhizoctonia as contact and volatile
treatments

• REFERENCES
• Rosa E.A.S., Heaney R.K. Fenwich G.R. and Portas
  C. (1997) Hort. Rev. 19 99-215
• Lazzeri L., Manici L.M., Leoni O. and Palmiei S.
  (2000) Acta Horticulturae 513, 53-61.
• Lazzeri L., Manici L.M., (2001) HortScience
  36(7) 1283-1289

Fig. 4 Pellets of Brassicaceae dried plants