Experiments on the control of the olive fly, Dacus oleae (Gmel.), by the combined effect of insecticides and releases of gamma‐ray sterilized insects

Abstract

A 2‐year pilot test in Kassandra (Northern Greece) showed that the olive fly infestation was maintained at low levels by a technique that combined 2 bait sprays followed by weekly releases of gamma sterilized flies reared artificially in the lab. The 1st spray was with Lebaycid while the 2nd, 3 weeks later, with Dimecron®. Releases started 2 weeks after the 2nd spray. The release area was about 0.4 km2 with ca. 600 olives trees. Two control olive groves were located near the release area, the nearest at a distance of ca. 1,000 m from its periphery. Sterilized flies were released from the ground. In the 1st year, flies were irradiated at the adult stage while in the 2nd at the pupal stage in nitrogen. Releases started before fruits became suitable for oviposition and stopped in November when cold weather diminished fly activity. Of major importance was found to be the timing of spray and releases. In the 1st year a major problem was fungal infestations accentuated by the excessive stinging of fruits from released females. In the 2nd year we had no such problem since insects were sterilized at the pupal stage and thus did not produce eggs. Zusammenfassung Untersuchungen zur Kontrolle der Olivenfliege, Dacus oleae (Cmel.) Zweijährige Versuche auf der Halbimel Kassandra (Nord‐Griechenland) haben gezeigt, daß der Olivenfliegenbefall niedrig gehalten werden konnte, wenn eine Technik angewendet wurde, die aus zwei Insektizid‐Köder‐Spritzungen und wöchentliche Freilassungen von künstlich gezüchteten sterilen Fliegen (Co60 γ‐Strahlen) bestand. Der erste Insektizid‐Einsatz erfolgt mit Lebaycid, der zweite mit Dimecron®. Die Freilassung von Fliegen folgte 2 Wochen nach dem zweiten Insektizid‐Einsatz. Das Versuchsfeld hatte 600 Bäume und war 0,4 km2 groß. Zur Kontrolle dienten 2 Olivenhaine, die über 1000 m vom Freilassungsgebiet entfernt waren. Die sterilen Fliegen wurden aus dem Boden freigelassen. Im ersten Versuchsjahr wurden die Fliegen als Jungadulten, im zweiten als späte Puppen in Stickstoff bestrahlt. Die Freilassung von Fliegen begann, ehe die Olivenfrüchte befallsreif waren und endete im November, wenn das kalte Wetter die Flugaktivität der Fliegen beendete. Sehr wichtig für den Erfolg war die Bestimmung der richtigen Zeit für den Insektizid‐Einsatz und die Freilassung. Im ersten Jahr bildete ein pilzlicher Befall der Früchte ein Problem, der im Zusammenhang mit den zahlreichen Stichen stand, welche die freigelassenen Weibchen in die Früchte bohrten. Im zweiten Jahr bestand dieses Problem nicht, weil die Fliegen als spate Puppen bestrahlt wurden und die Weibchen keine Eier produzierten, so daß die Anstiche wesentlich reduziert wurden.

A basis for the renewal of sterile insect technique for the olive fly, Bactrocera oleae (Rossi)

“…Finally, irradiation with 11 krad (110 Gy) in late pupal stage in N 2 atmosphere, as well as with 11 krad (110 Gy) on young adults in air, produced almost complete sterilization in both sexes. N 2 irradiation improved sexual competitiveness, as compared with irradiation of late pupa with 8 krad (80 Gy) in air (Economopoulos 1977). A single successful mating of female OLF fertilizes all eggs for the whole female life (Tzanakakis 1967; Economopoulos et al.…”

“…Following the development of a reliable artificial mass‐rearing system, a 2‐year SIT pilot field test was organized during the early 1970’s in an olive plantation (of about 600 trees) in the Kassandra peninsula of Halkidiki near Thessaloniki, Northern Greece (Economopoulos et al. 1977).…”

Genome size estimation with quantitative real‐time PCR in two Tephritidae species: Ceratitis capitata and Bactrocera oleae

“…On the other hand, the olive fruit fly, Bactrocera oleae , is a very specialized insect pest, associated exclusively with the olive fruit, causing extensive damages in the olive production in all olive‐producing countries (Mazomenos 1989). Contrary to the medfly, its genetics and genomics is relatively poorly developed, a fact that has hindered the development of effective SIT‐based approaches to its control (Economopoulos et al. 1977).…”

Isolation, annotation and applications of expressed sequence tags from the olive fly, Bactrocera oleae

“…Till now its control has been based mainly on the use of chemical pesticides. In the early '70s, eVorts to employ the sterile insect technique (SIT) against this insect were unsuccessful (Economopoulos et al 1977), principally due to the low competitiveness of the released mass-reared males compared with the wild ones (Economopoulos and Zervas 1982). The method relies on the mass-rearing, sterilization and release of thousands of competing insects that could theoretically result in nonproductive mating with the wild population.…”