Influence of abiotic factors on olive black scale (Saissetia oleae/Olivier) development | Vpliv abioticnih dejavnikov na razvoj oljkovega kaparja (Saissetia oleae/ Olivier)
2007
Koren, T., Ljubljana Univ. (Slovenia). Biotechnical Fac., Agronomy Dept. | Milevoj, L. | Jancar, M., Ulica 15. maja 17, 6000 Koper (Slovenia)
In the last years, the olive black scale (Saissetia oleae/Olivier) in Slovenian Istria propagated to such a degree to cause economic damage. Its bionomics was not known in our country; therefore, we decided to study its development related to some abiotic factors (air temperature, amount of precipitation, relative air humidity, solar irradiation, and pesticides). In 2003, olive trees planted near Ankaran in 1989 were tested. Working methods were based on: sampling of oleaginous branches from sprayed and non-sprayed Leccino trees (in June and July using Basudin 600 based on diazinon, in August and September using Perfekthion based on dimetoat), surveying conditions at the site, and sample checking under stereo-microscope in a laboratory; so as calculating the subjects and finding out their developing stages. At that very year the average month air temperatures were highly raised, solar irradiation prolonged, and the amount of precipitation reduced, compared to many years' average. In the beginning of April, the scales were in 1st larval stage, 2nd larval stage, and imagoes. Oviposition began on April 21; eggs hatched on June 1. Because of unfavourable weather conditions, the mortality rate of 1st larval stage on control trees was nearly 90 %. 2nd larval stage and 3rd larval stage entered into diapause in summer. Damage threshold was exceeded on June 15 (6.7 alive larvae per leaf) and June 29 (7.1 alive larvae per leaf). Insecticides' efficacy was nearly 100 %. In 2003, the black scale developed 1 generation.
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