Facts and figures
- The avocado is a tree native to Mexico and Central America
- Avocados are adaptable trees and can be grown in a range of (frost free) climates across Australia
- Avocado trees will need supplementary irrigation all year, regardless of climate
- The trees are susceptible to phytophthora root rot, a devastating disease that can kill trees
- The first commercial-sized avocado crop should be harvested three years after planting
- Avocados are harvested by hand and can be easily damaged, decreasing marketability
Due to the avocado tree’s climate adaptability, the industry is spread across Australia, ensuring year round supply. Avocado production takes place in the north and south of Western Australia, the TriState region (the irrigated regions of the lower Murray Valley where the borders of New South Wales, Victoria and South Australia meet), central and northern coastal New South Wales, and south east and central coastal regions and Atherton Tablelands of Queensland.
Avocados are evergreen, therefore they can be planted at almost any time of the year. Planting holes should be large enough to take the root system comfortably but large holes are unnecessary. Ensure the soil is well broken up on the sides to prevent roots spiralling in the tree hole. Do not place fertilisers in the planting hole, as they can burn young tree roots.
币游注册Avocado trees can grow quite large (up to 20m) if canopy size is not managed, so row spacing is important. Spacings of 12 x 6m, 10 x 5m, and 8 x 4m (equivalent to 138–312 trees/ha) are popular. Generally rows should run north–south to allow better infiltration of sunlight.
币游注册Pruning of new plantings is not required as avocado trees generally shape themselves. However, in order to create a bushier, more compact tree that is easier to manage, strong upward growing tips should be pinched out to promote side shoots during the first two years of growth. Any branches causing overcrowding and shoots from below the grafted area should be removed. As they grow, trees will require regular pruning to manage the canopy size and fruiting capacity.
币游注册Fertiliser rates will depend on a range of factors, including tree size, variety, soil type and irrigation. It is recommended that leaf analysis be undertaken in order to identify fertiliser needs. The New South Wales Department of Primary Industries includes detailed information on fertiliser needs.
An important point to remember is that avocado trees are evergreen and in most regions will require irrigation all year, including dry spells during winter. They are very sensitive to moisture stress, especially during flowering, fruit set and fruit development. During these critical periods the soil profile should be monitored to ensure it does not dry out. Annual supplementary water needs vary with region, from 3–5ML/ha in subtropical regions to 12–15ML/ha in Mediterranean regions.
Weeds, pests, and diseases
币游注册Weeds compete with newly planted trees for water and nutrients, therefore weed control before planting is important, as is mulching of the rows after planting. In a well-maintained mature orchard, the inter-row area is mown regularly to assist access to the trees and planting rows are mulched or sprayed with herbicide to minimise weeds.
币游注册Avocado is susceptible to a number of pests and diseases, whose distribution is influenced largely by climate. State departments of agriculture provide information on pests and diseases, and their management, see (Queensland) and (New South Wales) for more detailed information.
The most serious disease of avocado is phytophthora root rot, which can kill trees, and is caused by the soil-borne fungus Phytophthora cinnamomi Rands. It is a particular risk to trees that are sited in poorly drained soils.
As root rot is present in nearly all Australian orchards, root rot control is an ongoing management task for horticulturalists. As its name suggests, root rot destroys the root systems of trees and inhibits their ability to take up sufficient water or nutrients. Effective control of the disease involves good horticultural practice and an integrated management, which includes effective drainage, mulching, appropriate irrigation management, fungicide treatment and suitable soil pH of about 5.5.
Plant Health Australia has developed an for the avocado industry.