Almond scale

The almond scale (Pulvinaria amygdali) is a member of the Coccidae family within the order Hemiptera. This sap-sucking pest is a significant threat to deciduous fruit orchards, particularly those in temperate and warm-temperate climate zones, where it can reach high population densities.

It primarily attacks stone fruit trees, including almond, peach, plum, apricot, and cherry trees. The insects infest the bark of twigs and branches, where they remain fixed throughout their adult life stage, continuously feeding on the plant's phloem sap, which deprives the tree of essential nutrients.

The lifecycle of the almond scale typically consists of one generation per year. The insect overwinters in the second-instar larval stage, tucked away in bark crevices or near buds. With the onset of spring, these larvae emerge, complete their development, and produce a distinct white, cottony ovisac that contains the eggs, protecting them until hatching.

Damage caused by this pest is twofold. Direct damage involves the weakening of the tree due to sap extraction, which can result in stunted shoot growth and reduced fruit size. Indirect damage occurs through the secretion of honeydew, which fosters the growth of sooty mold; this black layer covers the leaves, severely impairing photosynthesis.

Management strategies for the almond scale rely on an integrated approach. Cultural practices such as pruning and thinning help ensure that trees have better airflow, which creates a less favorable environment for the scale. Chemical control is most effective when targeted at the crawler stage, utilizing systemic insecticides or dormant oil applications in the early spring.

• Regular pruning to improve canopy ventilation.
• Targeted insecticide applications during the crawler stage.
• Dormant oil sprays to suppress overwintering populations.
• Encouraging natural predators such as lady beetles and parasitic wasps.