Ecological and Biological Study of Black Scale Insect Saissetia oleae (Bern) on Olive Trees in Quneitra

Nissreen Deab
General Commission for Scientific Agricultural Research-
Quneitra  Research Center
Faculty of Agriculture, Damascus University,
2010

Abstract

This research was conducted to study the life cycle of Saissetia oleae B on olive (Variety Mawe) and the impact of topographic and climatic factors on spread and distribution of it stages during the growing season (2007-2008) at the Agricultural Research Center of Quneitra. The results showed that the female insect winter as mature females began to lay parthenogenesis eggs in late May. The eggs began hatching in the first of June and continued hatching and the emergence of Nymphs until September (this late Nymphs hatching can not complete the growth and ending with death), and reach peak mid-June, but often. The Nymphs growth into the young females in late June and continue growth and developing to mature females until October. S. oleae has one generation per year and the completion of generation took 90 days.
The results showed that the maximum significant population density of nymphs occurred on leaves compared with branches and floral clusters which averages (6.27, 1.76 and 0.74, respectively), while the differences were insignificant between the density of young and mature females and them distribution on various plant parts.
The highest numerical density of the various stages of insect on leaves was in June, July and August, but it decreased after the immigration large numbers of the nymphs to winter as mature females on branches to reach the highest numerical density of the insect on the branches in October, while the moral significant density of the insect on the floral clusters was in August.
And the results of study the effect of topographic and Climatic Factors on spread and distribution of Saissetia oleae B stages showed that significantly  negative correlation between the population density of the nymphs and temperature (R=-0.63), and insignificantly positive correlation with humidity (R=+0.31), while it was significantly negative with day length (R=-0.70).The young females density showed insignificantly positive correlation with temperature (R=+0.11) and day length (R=+0.29), while it was insignificantly negative with humidity (R=-0.06).The correlation between mature females density and each of temperature and humidity was insignificantly positive (R=+0.35, R=+0.21, respectively) and insignificantly negative with day length (R=-0.12).The low winter temperatures to (-5oc) led to the death of large numbers of insects and the rate of death in winter of 2008 (46%) as a result of continuation of the frost for a period of 26 days. As for the influence of topographical factors, the results showed the highest significant population density of the insect was in the sector which distinguished deep soil and high coverage rate compared with the two sectors distinguished shallow soils and low coverage.