Saissetia oleae

Olivier cochenille-noire1

Saissetia oleae (Olive Scale) is a species of scale insect that is a significant pest of olive trees. This insect is known for its damaging effects on olive production by feeding on the sap of the trees, which can lead to decreased growth, reduced yield, and in severe cases, the death of the tree. The olive scale is found in many parts of the world where olives are cultivated, including the Mediterranean region, parts of Africa, and California in the United States.

Description

The adult female Saissetia oleae is oval in shape and dark brown to black in color. It measures about 2 to 4 mm in length. The males are smaller, winged, and less commonly observed. The scale insects protect themselves with a hard, waxy covering, under which they feed on the plant sap.

Life Cycle

The life cycle of Saissetia oleae includes several stages: egg, nymph (crawler), and adult. Females lay eggs underneath their protective scale. Once hatched, the nymphs, also known as crawlers, begin to move around in search of a suitable feeding site. After settling, they start feeding and gradually develop into adults. The olive scale can have multiple generations per year, depending on the climate.

Impact on Olive Trees

The feeding activity of Saissetia oleae extracts vital nutrients from the olive trees, weakening them. This can lead to a reduction in fruit size and quality. Furthermore, the scales excrete a sticky substance known as honeydew, which can lead to the growth of sooty mold on the leaves and fruit. This mold further reduces the plant's ability to photosynthesize and can make the fruit unmarketable.

Management

Management of Saissetia oleae involves a combination of cultural, biological, and chemical methods. Monitoring the population levels of the scale is crucial to determine the need for control measures. Natural enemies, such as parasitoid wasps, play a significant role in controlling olive scale populations. In some cases, the application of horticultural oils or systemic insecticides may be necessary, especially when infestations are severe.

Cultural Significance

The olive tree is of great cultural and economic significance in many regions, particularly in the Mediterranean. The impact of pests like Saissetia oleae on olive production can have significant economic consequences for olive growers and can affect the availability of olives and olive oil in the market.