Pythium, phytophthora and fusarium are some
of the most common diseases found in hydroponic plants. They can
spread rapidly throughout a system, are difficult to cure, and can kill
plants within a few days.
Integrated Pest Management (IPM)
The
3 ‘ingredients’ that must be present for disease outbreak to occur are a
fungal source, a suitable environment and a host. Therefore if you can
eliminate one or more of these ingredients it is possible to avoid disease
outbreak and / or prevent a disease from spreading.
The following management practices will
significantly reduce the risk of disease.
1. ‘General
hygiene’ & ‘system clean-up
between crops’.
2.
Regularly
sterilize
the nutrient solution: This will help prevent disease ingress via
the root zone.
3.
Humidity: Controlling
humidity will, for many
diseases, prevent spore germination. Keeping ‘relative humidity’ at 60-70%
offers the best compromise for both disease prevention and plant growth.
4.
Sterilize make-up water: Untreated surface waters (e.g. dam, creek,
lake) must be sterilised 24 hours prior to use. Note, new RO and scheme
waters are normally sterile. Also, because the quality of all waters
deteriorate during storage, they should be regularly sterilized and stored
in the dark.
5.
Use a
medium
that drains well: Poor drainage promotes fungal disease.
6.
Minimize plant stress: Maintain correct
water and air temperature,
light,
nutrient concentration
and pH. Doing this
will
help produce a strong, healthy plant that is best able to defend itself
against disease attack.
7.
Insects
spread disease from one plant to another via sap transfer.
8.
Seeds/ cuttings: Ensure they are from a reliable source and sterile.
Be careful, looks can be deceiving. An incubation period is required for
spores to germinate and become recognizable. Also, diseases can lay dormant
for long periods of time until exposed to the correct conditions.
9.
Knowledge of disease type:
This is critical if
wanting to use chemical foliar sprays because most are useful against only
one or two specific diseases. The wrong choice of spray can be costly for a
large commercial operation. It is also useful because environmental
conditions can then be modified accordingly to lower the rate of disease
spreading. Note: many diseases have similar symptoms and therefore
professional diagnosis may be necessary.
