Agriculture Reference
In-Depth Information
13
OLIVE
(
Olea europea
)
Olive (family Oleaceae) has been grown as a source of
oil and fruit for thousands of years in the Mediterranean
region. There are currently about nine million hectares
of olives in the world, with the largest areas in Spain,
Italy, Greece and Tunisia. Most are used for oil
production.
The crop has been grown with varying success in Australia
for at least 150 years and production has increased since the
late 1990s as the health benefits of olive oil became more
apparent.
Olive prefers a Mediterranean-type climate, which has
cool winters with a warm, dry summer and autumn.
Well-drained, slightly alkaline soils are preferred with
an adequate water supply for irrigation.
Although dual-purpose varieties are available, usually,
different varieties are grown for oil or table use (pickling).
Plants are propagated from cuttings of one-year-old wood
struck in potting mixture then planted into the field
during the cooler months.
Trees bear commercial quantities of fruit after three to five
years and maximum yields are produced 10 to 15 years
after planting.
Australia remains free from several important diseases
and pests of the crop, emphasising the importance of
plant quarantine processes to prevent potential problems
entering the country.
Fig 13.1 Crown gall symptoms on a potted olive tree.
OLIVE KNOT
■
BACTERIA
Cause
The bacterium
Pseudomonas savastanoi
pv.
savastanoi
.
CROWN GALL
■
Symptoms
Rough galls or swellings of variable size occur on twigs,
branches, roots, fruit and leaves. Galls appear singly or as
groups and are more common on twigs and young branches,
but will also form around wounds on the main trunk. Galls
develop as small swellings 3-5 mm across and grow rapidly
into smooth, spherical green knots. The knots increase in
size as they mature, becoming darker and more furrowed.
Cause
The bacterium
Agrobacterium tumefaciens
.
Importance
The disease occurs mainly in potted nursery plants. Refer
to the chapter on Stone fruit.
