Survey on the control methods of Bactrocera oleae (Gmelin) in organic olive groves producing oil and table olives in Sicily

Summary

In Sicily there are several organic farms producing olive oil and the number of farms has grown in the last years. The control methods of Bactrocera oleae (Gmelin) used by Sicilian organic farms were surveyed in 2004 and 2005. After a bibliographic search on internet and by personal contacts, a sample of 30 organic farms in Sicily was chosen; 23 farms produce bottled extra-virgin oil and 7 produce table olives. Then farms were contacted by phone, some of them visited and olive growers were interviewed. For each farm were put together data about: interventions vs. the olive fruit fly, altitude, surface of the olive grove, olive cultivar, irrigation method, harvesting period, milling procedure, product destination and production results in 2005 and in the previous years.
From collected data we can say that obtaining oils of excellent quality and table olives of good quality in organic farming is surely possible; the early harvesting and a quick milling (for the oil) let to obtain good results.
The most used interventions are: mass trapping with ammonium carbonate, pheromone and pyrethroids, bottled-traps baited with sardines, yellow sticky traps, sprays with kaolin, Bordeaux mixture or pyrethrum, but there is more than one third of sampled oil producers not using any control method except early harvesting and a quick milling.
Unfortunately the organic farms producing table olives in Sicily are very few, perhaps because, differently from olive oil producers, table olive plantings are almost all young and the experience of growers in such organic cultivation is not strong. Also these growers prefer to use mass trapping to control olive fruit fly, but best results were achieved by farmers spraying kaolin, rotenone or copper hydroxide.