(IPPM) in Vegetables - Vegetableipmasia.org

Resource Manual on IPPM in Rice
World Education Philippines, Inc.
nematodes to the surface so the heat can destroy them. The soil should also
be allowed to cool down for a few days before sowing the seeds.
Solarization can be combined with another soil sterilization method. With
this method a large amount of organic material is incorporated into the soil
before applying the plastic sheets. A better sterilization effect may be
obtained and organic material may be added to the soil to improve soil
structure and fertilization.
· Use of Sub-soil
When damping-off diseases is a problem in an area, and there is no
possibility to shift the nursery to another site, the use of sub-soil may be an
alternative to reduce the chance of damping-off disease.
This method is practiced in some parts of Indonesia and is found to have
very good results. Since most of the damping-off causing organisms live
on top layer of the soil, the top layer of the soil must be removed about 30
cm in an area close to the nursery bed. It is recommended to mix the subsoil
with some compost.
· Biofumigation
Soil-borne pests and pathogens can be suppressed by chemical compounds
that are released during decomposition of certain crops. This is called
biofumigation. The chemical compounds that are able to kill or suppress
pathogens are principally isothiocyanates. Those crops with
biofumigation potential are used as rotation crop, a companion or a green
manure crop.
· Biological Soil Sterilization
Another relatively new method of soil sterilization, comparable with
biofumigation is being studied where soil sterilization is achieved by
micro-organisms that occur naturally in the soil. It requires air-tight plastic
sheets. The fresh plant material (from previous crop or green manure) is
worked into the soil deep and homogeneous. The field is watered and
covered with an air-tight plastic sheet (0.12-0.15 thick), properly fixed at
all sides. The sheet is left on the field for 6-8 weeks.
Within a few days of applying the plastic sheet, the oxygen, the microorganisms
cannot break down the organic material the usual way (into
carbon (CO 2 and water or H 2 O) so they switch to fermentation. During this
fermentation, several degradation products are formed and after some
time, a biogas called methane, is formed. Also, the concentration of
carbon in the soil increases. The fermentation products, the biogas
methane and the carbon are thought to play an important role in the
suppression of some soil pathogens and nematodes. The effects are better
at higher temperatures.
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