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The species of the family Syrphidae are one of the most important predators of the peach leaf aphids on tobacco. In the complex food chain, aphidophagous hoverflies are attacked by a wide range of parasites. During tobacco vegetation, in the Prilep area, we applied the following methods: survey of 20 tobacco stalks and survey of 100 tobacco leaves, in 10 days interval, 2003-2005. The prime material collected from the nature, further is cultivated and analysed under laboratory conditions. Parasited larva of Syrphidae, feeds with aphids and perform its bioregulatory role. Parasite species are activated after the larva of hoverflies is transformed into a puppet stage. They are feeding on tissues and organs of the hoverflies and destroy them. Were identified three parasite species from superfamily Chalcidoidea, eclosed from pupae of hoverflies: Pachyneuron grande (Pteromalidae), Pachyneuron cf. grande (Pteromalidae) and Syrphophagus aeruginosus (Encyrtidae). The most numerous is the parasitic specie P. grande. It was registered as a parasite on: Sphaerophoria scripta, Sphaerophoria rueppelli, Episyrphus balteatus, Scaeva pyrastri and Eupeodes corollae. P. cf. grande is a parasite on: S. scripta and S. rueppelli. S. aeruginosus is a parasite on: S. scripta, S. rueppelli, S. pyrastri and E. balteatus. The emergence of parasitic species depends on the occurrence of host-hoverflies, while the emergence and development of aphidophagous hoverflies depends on the occurrence of the peach leaf aphids on tobacco and climate conditions of the area. This study may contribute in strategies of biological control of plant pests and IPM implementation. |
