Seasonal dynamics and spatial distribution of black scale insect, Saissetia oleae (Olivier) on olive trees, and role of associated predators
DOI:
https://doi.org/10.64171/JAE.6.2.10-18Keywords:
Saissetia oleae, Seasonal abundance, Horizontal distribution, Vertical distributionAbstract
Olive (Olea europaea) is an ancient, drought-resistant tree cultivated for several thousands of years, primarily in the Mediterranean region, for oil and table fruit. The olive black scale insect, Saissetia oleae (Olivier) (Coccidae: Hemiptera), is one of the key pests of olive. The seasonal abundance and spatial distribution of S. oleae were investigated over two consecutive seasons; from October 2023 to September 2024 and from October 2024 to Septemb er 2025. Populations exhibited clear annual fluctuations, with winter declines followed by pronounced spring and summer peaks. Immatures dominated throughout both seasons, reflecting continuous recruitment and extended crawler activity. Horizontal distribution showed higher insect densities on south and west directions of the canopy, while the lowest numbers were detected on north direction. Vertical distribution revealed that the middle level of the canopy harbored the highest populations of both immatures and adult females, whereas the lower level contained the fewest individuals. Two coccinellid predators; Coccinella undecimpunctata L. and Exochomus flavipes (Thunberg, 1781) (Coleoptera: coccinellidae), were recorded associated with S. oleae during both seasons. Their populations showed significant positive correlations with the total scale population, indicating a numerical response of the predators to host abundance. Spring and early summer peaks indicate critical windows for targeted management. Overall, the findings highlight the nearly year-round activity of S. oleae, and the influence of canopy microhabitats on population distribution.
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