Seasonal occurrence of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) in southern Syria

摘要

Population fluctuations of the Mediterranean fruit fly (medfly), Ceratitis capitata, were investigated between 1999 and 2001 at several locations representing fruit production areas in the southern part of Syria (Damascus Ghota, Zabadani, Sargaiah, Rankus, Orneh and Ain Al-Arab). Medfly adults were monitored weekly all year around using Jackson traps baited with trimedlure dispensers. Larvae were also sampled in Damascus Ghota by collecting fruits from ripe or ripening fruit trees and recording the number of larvae emerged from these fruits. In addition, suspected overwintering refuges were sampled at weekly intervals during the three coldest months of the year (December – February) and the number of collected larvae was recorded. The results of trap catches and fruit sampling studies showed a similar pattern of occurrence of medfly populations in the study areas, particularly in Damascus Ghota, during the three years of the study. In Damascus Ghota, flies were caught continuously from early June to late December with some variability between years. Two distinct periods of high fly activity were observed: the first one occurred in August and the second in November with a much higher amplitude. In general, seasonal fluctuations in the pattern of occurrence were influenced by differences in temperature and abundance of preferred host fruits. Traps on fig Ficus carica and oriental persimmon Diospyros kaki trees caught the highest numbers of flies, and fruits collected from these trees showed the highest level of infestation, reaching 100% for fig fruit late in the season. Sampling fruits (in Damascus Ghota) from trees during the three coldest months of the year showed that a small population of medfly larvae was able to survive winter conditions in prickly pear Opuntia vulgaris fruit left on the trees. In the other areas of the study (Zabadani, Sargaiah, Rankus, Orneh and Ain Al-Arab), only a few flies were caught.