Californian scale insect - Quadraspidiotus perniciosus Comst

Damage:

The scale insect sucks sap from the bark of the trunk, branches, twigs, fruits and leaves;

Under heavy infestation the bark cracks and dies, individual branches dry out, and later the entire tree dies;

On the twigs and fruits, at the site of damage, wine-red to purple spots are formed, the leaves fall, the shoots become deformed, the bark of the twigs cracks, and the fruits lose their commercial appearance.

The pest attacks about 200 plant species – causing severe damage to apple, pear, plum, peach and apricot.

It overwinters as a first-instar larva on the bark of the twigs and trunk, which completes its development during apple flowering.

It spreads through planting material.

Control:

During the dormant period, control measures are directed against the overwintering stage – the larvae;

Until bud swelling of apples and pears, treatment should be carried out with a plant protection oil, which acts by asphyxiation – it forms an oil film that covers the scale of the overwintering larva and deprives it of oxygen, as a result of which it dies;

When treating with plant protection oil, the overwintering eggs of the European red mite are also destroyed, at an established density of 60–80 overwintering eggs per 10 cm twig in apple and 40–50 eggs per 10 cm twig in pear, as well as providing action against scale insects, psyllids, weevils, etc.;

The product may be added to the fungicidal spray solution or used alone.