Avocado | Ortho

Plant:

Avocado

Adaptation

California, Hawaii, Puerto Rico, and Florida

Pruning

During the summer, prune lightly to shape the tree. Remove weak, diseased, or dead twigs and branches. Thin the fruits only if there is danger of branch breakage from excessive weight.

Soil

Use a garden soil that''s high in organic material.

Water

Water deeply and thoroughly when the soil is barely moist.

Fertilizer

Fertilize with plant food formulated for avocados.

Harvest

Avocados do not soften on the tree, so it is difficult to tell when the fruit is ripe. Purple or dark varieties are usually mature when the fruit starts to darken. When fruits of green varieties begin to mature, the bright green color diminishes, a yellow tinge appears on the skin and stem, the fruit becomes smoother, and small corky areas may appear on the skin. The seed coat will turn brown and papery. When picking, cut the stem as close to the fruit as -possible without injury.

Light

Full sun.

Animal Damage -

Animal Damage

Cercospora Spot -

Cercospora Spot

Fruit Scab -

Fruit Scab

Omnivorous Looper -

Omnivorous Looper

Phytophthora Root Rot - Avocado

Phytophthora Root Rot

Whitefly - Avocado

Whitefly

Animal Damage -

Animal Damage

Description

Fruit has large holes chewed in it. In some cases, the entire fruit except for the seed may be eaten. Fruit loss is heaviest during the ripening season, but some losses may occur earlier. No insects or similar pests can be found doing the damage.

Analysis

Birds, squirrels, and rats are fond of avocados and can destroy large quantities of fruit. Birds prefer immature fruit; rats and squirrels tend to prefer mature or nearly mature fruit.

Solution

When the problem becomes too severe on mature fruit, pick all remaining fruit. Traps may be used to catch squirrels and rats, but birds cannot usually be discouraged easily. Netting may have to be placed over fruit for protection. Scare devices are sometimes effective in controlling animal pests.

Cercospora Spot -

Cercospora Spot

Description

Leaves are covered with small angular brown spots that often go through the leaf. They may grow together to form larger spots. During moist periods throughout the year, spores are produced in grayish tufts on both sides of the spot. Severely infected leaves often drop. Fruit may also become infected and develop brown depressions.

Analysis

This plant disease is caused by a fungus (Pseudocercospora purpurea) that infects avocado leaves and fruit. Old leaf infections are the usual source of spores. In some years, much leaf loss can occur, weakening the tree and slowing fruit development. When the fungus attacks the fruit, the spots often provide convenient entryways for other fungi that rot the fruit.

Solution

Spray the tree with a fungicide labeled for cercospora spot, following label directions.

Fruit Scab -

Fruit Scab

Description

Fruit develops raised, dark brown to purplish brown, scablike areas. Spots may be scattered or grown together to form large, scabby areas that cover the fruit. Fruit may be deformed or dwarfed. The disease does not affect the flavor of mature fruits.

Analysis

This disfiguring disease is caused by a fungus (Sphaceloma perseae) that is carried over from one season to the next on stem and leaf lesions. Young fruits are usually infected just after the petals fall from the flowers. As fruit ages, it becomes more resistant to infection, but it does not acquire immunity until it is more than half-grown.

Solution

Spray the entire tree with a fungicide labeled for fruit scab, following label directions.

Omnivorous Looper -

Omnivorous Looper

Description

The upper surfaces of leaves may be stripped away, with only a thin brown membrane remaining; or the leaves may be entirely chewed between the veins. The fruit may be distorted or scarred. Striped yellow to pale green worms up to 21/2 inches long are eating the leaves. These worms may be seen on the leaf edges or in between two leaves webbed together. Severely infested trees may be partially defoliated.

Analysis

Sabulodes caberata This worm, the larva of a brown night-flying moth with a wingspan of up to 2 inches, attacks avocados and other trees and shrubs. Although the moth is nocturnal, it may be found during the day on the undersides of leaves, where it lays eggs. The larvae that hatch from these eggs feed on the foliage and developing fruit for about 6 weeks. Then they pupate inside leaves that they web together. Larval damage occurs year-round but is most severe during the spring and summer.

Solution

Several natural predators keep this pest under control, including tiny wasps, flies, viruses, and fungi. If infestation is severe, spray with a bacterial insecticide labeled for this pest, following label directions.

Phytophthora Root Rot - Avocado

Phytophthora Root Rot

Description

Leaves are smaller than normal, yellowish and may wilt and drop. The foliage is sparse, with little new growth. Entire branches may die, and the fruit is often small. Eventually the entire tree may wilt and die, even though the soil is sufficiently moist. The bark on the trunk just above or below the soil line may be darkened.

Analysis

This plant disease is caused by a soil-inhabiting fungus (Phytophthora cinnamomi) that infects many fruit, nut, and ornamental trees and shrubs. It penetrates the roots and crown of the tree. As the fungus decays the sapwood, the flow of water and nutrients is blocked, eventually resulting in the death of the tree. The fungus is spread by infected plants and by infested soil and soil water. Phytophthora root rot is greatly favored by wet or poorly drained soil. Trees planted in lawns, flower beds, or other moist or poorly drained areas are highly susceptible to this fungus.

Solution

Once the fungus becomes established in the soil, it will remain indefinitely. To prolog the lives of mildly infected trees, remove the soil from around the crown of the tree, exposing the major roots. Always keep this area dry by providing drainage away from the tree. Avoid overwatering. Remove severely diseased and dying trees. Do not replant susceptible plants in the same area.

Whitefly - Avocado

Whitefly

Description

Tiny white-winged insects feed mainly on the undersides of leaves. Nonflying, scalelike larvae covered with white, waxy powder may also be present on the undersides of leaves. When the plant is touched, insects flutter rapidly around it. Leaves may be mottled and yellowing.

Analysis

This insect is a common pest of avocado. The four-winged adult lays eggs on the undersides of leaves. The larvae are the size of a pinhead, flat, oval, immobile, and semitransparent. In about a month, they change to the winged adult form. The larvae are more damaging because they suck more sap from the plants than do the adults. They cannot digest all the sugar in the sap, and they excrete the excess in a sticky material called honeydew, which coats the leaves and may drop from the plant onto surfaces below.

Solution

Remove heavily infested leaves. Vacuum plants to pick up adults. Apply an insecticide labeled for edibles, or houseplants if grown indoors, following label instructions. Treat plants at night when insects are not flying. Continue treatment if the problem continues.