Determining the Most Suitable Time to Harvest Olive Fruits Infected with Olive Fruit Fly ‘Bacterocera oleae’ Larvae Based on the Quality and Quantity of Fruit Oil

This research aimed to determine the most suitable time to harvest olive fruits (Olea euopeae cv. Zard) infected with olive fly larvae based on the quality and quantity of the extracted oil. The experiment factors included the fruit type at two levels (1: infected fruits, 2: healthy fruits) and the harvest time at six levels (0: the time of olive fly larvae exit, 1: one week after the fly larvae exit, 2: two weeks after the olive fly larvae exit, 3: three weeks after the olive fly larvae exit, 4: four weeks after the olive fly larvae exit and 5: five weeks after the fly larvae exit). The fresh oil of fruit was extracted and analyzed for measuring qualitative and quantitative characteristics. The results showed that the effect of fruit type was significant on the extinction coefficient at 232 and 270nm (K232 and K270). The effect of harvest times was significant on K320, oil percent (p≤0.05) and acidity (p≤0.05), but had no significant effect on K270 and peroxide (p≤0.05). The interaction effect of fruit type and harvest time was significant only on acidity (p≤0.05) and was not significant on other parameters. Based on the results, the healthy fruits had lower acidity and peroxide number and higher oil percentage than infected fruits and therefore had better quality. It can be concluded that the best time to harvest the fruit was two weeks after the larva leaves the fruit because, after that, the negative effects of olive fly larvae on the quantity and quality of fruit oil are high, while before that, quality indicators of the fruit are not affected by olive fly larvae.