Liothrips oleae Costa, popularly known as olive spider, Liothrips oleae Costa, belongs to the order of the tisanópteros (small neoptera insects). Its incidence is usually small and is considered a secondary pest of the olive grove. The insect is also called black louse, due to its dark color and small size.
The plague was identified at the end of the 18th century and caused significant damage to olive plantations located in La Rioja.
Generations of Liothrips oleae Costa
The plague Liothrips oleae consists of three annual generations:
First generation: adults who have resisted winter begin their activity when temperatures begin to soften and the olive tree resumes its vegetative activity. The generation has a rapid development taking to complete between a month and a month and a half depending on the weather conditions. During their development phase the nymphs feed on the sap of the leaves and shoots of the olive tree. Unlike the black scale olive tree the nymphs of the olive spider have mobility.
Second generation: develops during the summer, the nymphs take advantage of their mobility to seek refuge during the warmest hours of the day. During this phase they also feed on the olives.
Third generation: During the end of summer the third and last generation of the black louse begins. Finally, adults take refuge in sweeping galleries, tuberculosis cracks and other small cavities where they shelter from winter cold.
Damages caused by Liothrips oleae
When the populations of olive spider are very high, the olive tree reduces its vigor. As a consequence the vegetative growth of sprouts and olives is reduced. Visibly leaves and small olives, deformed and with grayish necrotic spots are visible.
Arañuelo del Olivo Treatment
Hard winters (with very low temperatures) can kill most of these insects.
During the early 20th century, currently unauthorized chemicals were used for the treatment. Some known are the zotal, lysol, hydrocyanic acid and soapy emulsions of petroleum.
Physical measures were also applied such as the bark, vareo and pruning of the olive trees.
Products used in 2017:
Modern biological pesticides are currently used, such as the bacterium Bacillus Thuringiensis Aizawai and Bacillus Thuringiensis Kurstaki.
The Liothrips oleae Costa is also controlled with applications or insecticide treatments such as the popular dimethoate.
In case of application of treatment, we must ensure that the product is authorized and follow the indications present on the package.
Recommended Reading
Complete information on diseases or pests of the olive tree: Verticilosis, Prays oleae, Xylella fastidiosa, Olive fly, Tuberculosis, Repilo, Olive Acariosis, Otiorrinco, soapy olive…
Warning
We have translated the information on our website from Spanish to English. Note that some words may have seen their meaning altered during their translation.