How to Obtain Inoculum
Ideally the seed suppliers themselves are able to provide the appropriate strains of
Rhizobia inoculum. However it does not travel well, and it is destroyed at temperatures
of about 35°C, so if possible inoculum should be obtained locally. Local agricultural
research centres are sometimes able to advise on sources etc.
If it becomes necessary to make a special order request for inoculum, the timing is of
course of the essence as the inoculum should be new and fresh at the time of planting.
Several weeks are usually needed to prepare a significant volume of inoculum.
The variety names of the crop to be inoculated should be known, and provided to the
people producing the inoculum.
Even in optimum storage conditions inoculum should not be used after six months at
the longest. In cool but not refrigerated conditions it should not be kept for more than
about 3 months.
Seed Inoculation Procedures
- Mix 1 part of inoculum with 2.5 parts of water. 2. Pour this over the seed.
- Mix together so that every seed is covered. 4.Wait until the seeds do not stick
together, then mix again. 5. Sow as soon as possible, within three or four days if
possible, though the inoculum may still be viable after seven days if the conditions are
favourable.
Also known as seed dressing it is the chemical treatment of seed, especially cereals,
with fungicides and sometimes insecticides or other products, described below. The
principal purpose of treating seed is to reduce the spread of soil-borne and seed-borne
pests and diseases, and also to promote good seedling emergence and to minimise yield
loss. Seed is almost always treated by the seed supplier, though food growers and
farmers can quite easily treat their own seed with the appropriate equipment, which can
be made at home using a drum welded asymetrically onto a frame.
A coloured dye, normally red or blue, is usually added so that the seed can be seen
clearly by everyone to have been treated. Treated seed must never be used for human or
animal food, but should be safely stored in a dry place for the next planting season.
Inoculation of seed that has been previously treated requires that the inoculum
should be sprayed in suspension into the seed furrow just before planting, then covered
by soil together with the seed.
The traditional dressing for pest protection was gamma-HCH (formerly called
gamma-BHC), which is on the restricted use list. In the late 1990s Bayer released a less
toxic insecticidal seed dressing “Imadacloprid”, under the trade name “Secur”, mainly
for use with cereals. This has a mainly systemic action, against aphids (and other virus
vectors) in winter wheat and oats, but it also suppresses wireworm and leatherjacket
seed—the longer the delay before the seed is planted the more inoculum should be used:
is described below. The normal application rate is 7–10g of inoculum per kilogram of
If the inoculum is in its normal powder form, one relatively easy and effective method