Overwintering of Ceratitis capitata in Northern Greece
Studies were carried out in Northern Greece near Thessaloniki on the overwintering potential of Ceratitis capitata (EPPO A2 quarantine pest). They took place in a untreated orchard of various host plants (apple, pear, peach, apricot, quince, fig and persimmon (Diospyros kaki)), situated within the northern limits of establishment of the fly (40.3° north latitude). During three winters (1992-1995), larvae within various naturally infested fruits, pupae and adults were exposed to natural outdoor temperatures. Results showed that within the northern limits of its distribution, C. capitata overwinters almost exclusively in the larval stage inside fruits. In exceptionally mild winters a small proportion of pupae may also overwinter. The authors noted that the type of host fruit is important, as this may have an influence on the duration of larval stage. A host fruit which favour slow growth in conjunction with low winter temperatures, may enable the larval stage to persist throughout the winter. Observations made showed that certain host fruit, like apple and quince, which become infested in autumn and fall to the ground can remain in sufficiently good condition to provide a suitable refuge for C. capitata. The authors underlined the practical implications of their results which showed that a proportion of the larval population can remain inside host fruits for many months during winter. They feel that it may be impossible to eradicate C. capitata in short-term programmes (6-8 months), and that surveillance policy and conclusions regarding eradication should be based on trap detection made in summer and autumn when adults are active and not in other seasons where populations are very difficult to detect.
Sources
Papadopoulos, N.T.; Carey, J.R.; Katsoyannos, B.I.; Kouloussis, N.A. (1996) Overwintering of the Mediterranean fruit fly (Diptera: Tephritidae) in Northern Greece.
Annals of the Entomological Society of America, 89(4), 526-534.