Olive scale

Olive scale (Parlatoria oleae) is a significant agricultural pest belonging to the order Hemiptera and the family Diaspididae. It is widely recognized as a serious threat to Mediterranean fruit and ornamental tree cultivation due to its ability to colonize multiple hosts.

The pest targets a vast range of crops, primarily focusing on olives, but also severely impacting stone fruits such as peaches, apricots, and plums, as well as various ornamental species like lilacs and privets. It colonizes the bark, leaves, and fruits, often causing cumulative stress to the infested plants.

The biological cycle of Parlatoria oleae is highly dependent on temperature, with one or two generations occurring annually. Overwintering takes place as mated females on the bark. In spring, eggs are laid beneath the scale cover, leading to the emergence of crawlers, which represent the primary stage for dispersal and infestation of new plant tissues.

Damage caused by the olive scale is significant. By sucking sap from plant tissues, it creates necrotic spots on the fruit, which makes the produce unmarketable. Persistent infestations lead to canopy dieback, leaf drop, and overall reduction in tree vigor, significantly affecting long-term yield and tree health.

Control strategies involve a combination of chemical and cultural methods. Monitoring the emergence of crawlers is crucial for timing insecticide applications effectively. In addition, dormant-season treatments with horticultural oils can significantly reduce the overwintering population. Proper pruning to open the canopy also helps in managing the pest by reducing favorable microclimates.