Giant scale

Systematic position and identification: The giant scale (Leucaspis gigas) is a member of the order Hemiptera and the family Diaspididae. These armored scale insects are recognized by the protective covering they secrete, which shields them from environmental stress and makes them difficult to control through standard contact pesticides.

Host plants: The primary host for Leucaspis gigas is the olive tree (Olea europaea). However, the insect has been observed infesting a variety of other woody species, showing a particular preference for the bark and twigs of healthy, established trees within orchard ecosystems.

Biology and lifecycle: The insect's lifecycle consists of the egg stage, the crawler (nymph) stage, and the sedentary adult stage. The crawlers are the only mobile life stage, responsible for spreading the infestation to new branches or adjacent trees. Once a suitable feeding site is located, the nymph settles, loses its legs, and begins to develop its characteristic protective shield.

Damage and economic impact: Feeding by sucking plant sap, Leucaspis gigas causes direct physiological damage to the host. Heavy infestations lead to bark cracking, drying of twigs, branch dieback, and a general decline in tree vigor. In severe cases, the reduction in tree health significantly compromises yield quality and quantity in olive production.

• Implementation of early season monitoring for crawler emergence.
• Application of horticultural oils during the dormant period to smother insects.
• Targeted use of systemic insecticides during active growth phases.
• Pruning and removal of heavily infested limbs to reduce population pressure.
• Biological control through the encouragement of natural predators and parasitoids.