**Author details**

102 Olive Germplasm – The Olive Cultivation, Table Olive and Olive Oil Industry in Italy

lowest level of active infestation observed.

black olives (Cirio, 1971; Rizzo and Caleca, 2006).

ripening period only for cv. Tonda nera dolce suggests a possible role in determining the

Studies on cultivars Bardhi i Tirana, Carolea and Tonda nera dolce (Iannotta et al., 2007a) corroborate results obtained in previous investigations. Cultivars Bardhi i Tirana and Carolea were selected because they have low and high levels of susceptibility, respectively, to olive fly whilst cultivar Tonda nera dolce was selected because it shows high levels of cyanidine. Differences were found among the three cultivars in relation to active and total infestations and oleuropein and cyanidine contents. The lowest percentages of active and total infestations were observed on cv. Tonda nera dolce (8.62% and 20.12, respectively), while cv. Carolea had the most damage (29.00% and 49.38%, respectively). Cultivar Bardhi i Tirana showed intermediate values of active and total infestations. The low susceptibility found for cv Bardhi i Tirana, although greater than the susceptibility showed by cv Tonda nera dolce, might be due to the highest oleuropein content observed. The content of cyanidine in cv. Tonda nera dolce might be responsible for the lowest susceptibility found.

Cyanidine probably acts by giving olive fruits a dark colour during the early ripening stages. This may confuse female olive flies in drupe recognition resulting in a decrease in oviposition. This hypothesis is supported by the evidence that in herbivorous diurnal insects, visual cues may play an important role in the location of host plants and essential resources, such as food, mating, and oviposition sites (Prokopy and Owens 1983). This situation is very common for frugivorous Tephritid flies that feed and oviposit on fruits (Katsoyannos, 1989; Fletcher and Prokopy, 1991; Diaz-Fleischer et al., 2000; Prokopy and Papaj, 2000). A laboratory experiment investigating the effect of fruit colour on attracting olive fruit fly females was carried out by Katsoyannos et al. (1985). In this study, females were left to select for oviposition sites among hollow, hemispheric, ceresin wax domes of different colours. Yellow and orange domes were preferred for oviposition compared to domes of other colours. Red, blue, black, and white domes were the least preferred. Red, blue, and black correspond to the colour of ripening olives reached during the maturation stages. Fruit colour is genetically determined in some cultivars and is related to the content of anthocyanins. Olive fly females prefer green olives for oviposition compared to red and

The high content of phenolic compounds found in several cultivars is a resource in olive germplasm. Field researches demonstrated that a high content of phenolic compounds is related to low susceptibility to olive fly attacks and other parasites. Therefore, the planting of genotypes containing high amounts of these compounds may greatly contribute to a significant reduction of pesticides inputs. In addition, the presence of phenolic compounds in olive fruits is also associated with various benefits for human health deriving from high quality olive oil intake. Therefore, the conservation of olive intraspecific biodiversity preserves sources of genetic resistance to various pests. To preserve olive germplasm biodiversity in accordance with CAP directives and minimize pesticide use diversifying agronomic practices are strongly related. Strategic *B. oleae* control is thus a priority for safeguarding both environmental integrity and consumer health. The identification of genetic Nino Iannotta and Stefano Scalercio *Agricultural Research Council - Olive Growing and Oil Industry Research Centre, Rende (CS), Italy* 
