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Current pest and disease control practices aim at keeping crops healthy without producing catastrophic effects upon nature’s balance. If controls are regular and climate conditions are not extremely unfavourable, the quality and quantity of yield is guaranteed. In this respect, regular samplings and checks during the period which goes from the beginning of vegetative functions to harvest are of utmost importance because they help to limit pruning and to reduce the use of chemicals taking advantage of natural predators to control pests and diseases.

The “Oliva Tenera Ascolana” is very sensitive to the following factors causing plant illness:

A) Abiotic factors

(extreme cold, hail on branches and fruits, severe wind, long-lasting severe summer draugh)

B) Biotic factors

1) DISEASE (Olive Fly, Olive Moth, Black Scale, Olive Beetle, Nematode, Virosis)

2) PESTS (Fumagine of the olive tree, Sooty mould, Anthracnose, Crawn gall)

Pest/Disease

Features of Pest/Disease

Check-ups and Treatments

FUMAGINE
OF THE OLIVE TREE

(Cycloconium oleaginum)

The leaf blade (especially the upper one) shows brownish round spots whose borders turn yellowish in time.

The plant is more prone to develop the disease in highly dump periods (i.e. autumn and spring).

Prune to let air and light through the foliage. Do not give the plant too much nitrogen.

After harvesting, at the end of the dormant period and when vegetative functions start again spray the plant with alkaline Bordeau mixture. The plant usually stands up to the illness quite well.

SOOTY MOULD

(Capnodium oleaginum)

Large part of the foliage are coverd with greasy and sticky soot made up of hyphae and conidia flourishing on other parasites’ secretion

(e.g.: scales’secretion).

Eliminate insects found on the plant.

Cupric products can be used when the tree is dormant.

ANTHRACNOSE

(Gloeosporium olivarium)

Ripe drupes show sunken round areas. Very frequent in dump autumns.

Prune to let air and light through the foliage.

Cupric products can be used when the tree is dormant.

CROWN GALL

(Pseudomonas syringae sp. Savastanoi)

The plant is covered with galls of various dimensions grown on cracks caused by pruning, hail or frost.

Eliminate as much as possible the damaged parts and disinfect.

Use cupric products when the tree is dormant

OLIVE FLY

(Dacus o Bactocera oleae)

The fly cuts the epicarp and lays an egg into the mesocarp. When the egg becomes a maggot it digs a rather long tunnel which can reach the external part of the endocarp.

Some hymenoptera are natural predators of the fly.

Use pheromone traps to check the number of drupes being attacked. If more then 10% of the drupes is affected use active water-soluble products.

The plant is not very resistant to this illness.

OLIVE MOTH

(Prays oleae)

Maggots found on flowers and little fruits will repoduce themselves several times in autumn; they dig tunnels to reach and eat young leaves.

Eliminate the pest when fruits are as big as grains of pepper

BLACK SCALE

(Saissetia oleae)

The insect, as big as half a grain of pepper has an H-shaped drawing on its back.

It feeds on sap and produces execreta which attract the spindle tee.

There are several natural predators which attack the scale.

Treat with white oils when more than 3-4 scales per leaf are found in the period July-August.

OLIVE BEETLE

(Phloeotribus scarabaeoides)

The insect lays its eggs on the branches and the maggots which develop dig tunnels. More frequent when plants are weak and weather is dry.

Leave pruned branches under the tree, they will attract this beetle which will lay its eggs there. Remember to burn or disinfect the pruned branches.