''Saissetia oleae'' ( syn. ''Coccus oleae'') is a scale insect in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Coccidae The Coccidae are a family of scale insects belonging to the superfamily Coccoidea. They are commonly known as soft scales, wax scales or tortoise scales. The females are flat with elongated oval bodies and a smooth integument which may be cover ...

. It is considered one of the three main

phytophagous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...

parasites of the

olive tree The olive, botanical name ''Olea europaea'', meaning 'European olive' in Latin, is a species of small tree or shrub in the family Oleaceae, found traditionally in the Mediterranean Basin. When in shrub form, it is known as ''Olea europaea'' ...

(''Olea europaea''), together with the olive fruit fly (''

Bactrocera oleae The olive fruit fly (''Bactrocera oleae'') is a species of fruit fly which belongs to the subfamily Dacinae. It is a phytophagous species whose larvae feed on the fruit of olive trees, hence the common name. It is considered a serious pest in t ...

'') and the olive moth ('' Prays oleae''). Although it is a common parasite which occurs most often in olive trees, it is a polyphagous species, also attacking (but less frequently)

citrus ''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to ...

trees as well as various ornamental shrubs such as oleanders,

pittosporum ''Pittosporum'' ( or ) is a genus of about 200 species of flowering plants in the family Pittosporaceae. The genus is probably Gondwanan in origin; its present range extends from Australasia, Oceania, eastern Asia and some parts of Africa. ''Cit ...

s, sago palm, and

euonymus ''Euonymus'' is a genus of flowering plants in the staff vine family, Celastraceae. Common names vary widely among different species and between different English-speaking countries, but include spindle (or spindle tree), burning-bush, strawb ...

History

One of the first scientists who studied the insect in a scientific and modern way was Italian naturalist

Giuseppe Maria Giovene Giuseppe Maria Giovene (23 January 1753 – 2 January 1837) was an Italian archpriest, naturalist, agronomist, geologist, meteorologist, entomologist and ichthyologist. elogio-storico, pag. 9, note 8 He is best known for his studies on the "nit ...

. He wrote a publication entitled ''Descrizione e storia della cocciniglia dell'ulivo'' (1807) in which he answered Giovanni Presta who had denied the existence of the insect in the

Apulian it, Pugliese , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = , demographics1_footnotes = , demographics1_title1 = , demographics1_info1 = , demographic ...

provinces of Bari and

Otranto Otranto (, , ; scn, label=Salentino, Oṭṛàntu; el, label= Griko, Δερεντό, Derentò; grc, Ὑδροῦς, translit=Hudroûs; la, Hydruntum) is a coastal town, port and ''comune'' in the province of Lecce (Apulia, Italy), in a ferti ...

. Giovene showed that the insect was common in the above regions as well, even though it occurred less often. Moreover, Giovene discovered the male of the insect, which at that time wasn't known in Europe. In the ''Dictionary of Natural History of Paris'' (1816) (french: Nouveau dictionnaire d'histoire naturelle, appliquée aux arts, à l'agriculture, à l'économie rurale et domestique, à la médecine, etc.) it was written that "the male is not known" (french: Le mâle n'est pas connu).

Life cycle

The soft body of the adult female olive scale is concealed under a dark grey or brownish-black covering which grows and hardens over time. Male scales are not present in most regions and breeding is by

parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and developmen ...

. The female is generally immobile and lays up to 2,500 eggs in batches. The eggs are retained under the scale and hatch into

nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ...

known as "crawlers". These are mobile, emerging from under the scale and dispersing to other parts of the plant. They moult twice before becoming adult, and all life stages of the insect feed by sucking the sap of the host plant.

Distribution and hosts

''Saissetia oleae'' may have originated in South Africa but has spread around the world and now has a global distribution. It has been recorded feeding on 113 species of plant in 49 families. As well as being a serious pest of olive, it is one of the most important pests of citrus especially in the Mediterranean area, California, Florida and South America. The parasitic wasp ''

Metaphycus helvolus ''Metaphycus helvolus'' is a species of parasitic wasp in the family Encyrtidae native to South Africa. It is a parasitoid of soft scale insects and has been used in their biological control in California and Australia. Description ''Metaphycus ...

'' is native to South Africa and has been introduced to California where it has dramatically reduced incidence of this scale in citrus orchards.

References

External links

Agraria.org - Saissetia oleae

Agroambiente.info - Saissetia oleae
{{Taxonbar, from=Q1460473 Olives Agricultural pest insects Insects described in 1791 Coccidae