Postharvest Control of the Date Moth Ectomyelois ceratoniae ... - Iresa

stored dates and causes weight loss anddowngrading of the commercial value ofthe fruit (2, 14).Dates intended for export undergothe process of conditioning to preserveand improve their quality. Chemicalcontrol using fumigation is the mosteconomical tool for managing this storedpest in postharvest treatment (3). Methylbromide is still the primary insecticide ofpostharvest insect control for dates inTunisia and in several other countries (19,53). Nevertheless, the use of thisfumigant is being restricted because of itshealth and environmental damages (6).Moreover, the Montreal Protocol of theUnited Nations Environment Program(49) recommends the phasing out ofmethyl bromide by 2005 in developedcountries and by 2015 in developingcountries (33).Consequently, research of effectivealternative methods is needed. In recentyears, essential oils have received muchattention as pest control agents because oftheir insecticidal properties (42). Essentialoils are volatile and can act like fumigantsoffering the prospect for use in storedproductprotection (7, 15, 41, 44, 46).Eucalyptus (Myrtaceae) is one of themost cultivated genera in the worldincluding more than 700 species. Variousbiological properties have already beenattributed to the genus Eucalyptus, amongthem insecticidal activity against beetles(8), repellent action against Phlebotomuspapatasi (51) and larvicidal activity onculicids (10). Besides, eucalyptusessential oils are used for medicinal andpharmaceutical purposes (11, 12, 18, 26,37, 43). In Tunisia, 177 Eucalyptusspecies were introduced and acclimatizedinto more than 30 arboretums since 1957(23).The objectives of this study were todetermine the chemical composition ofthe essential oils of Eucalyptuscamaldulensis and E. rudis and toevaluate their fumigant toxicity againstnew emerged adults of E. ceratoniae.MATERIALS AND METHODSInsect rearing. A laboratory rearingcolony was established in the Laboratoryof Plant Protection at the Institut Nationalde la Recherche Agronomique de Tunisie(INRAT) from infested field-collecteddates. The moth was reared on anartificial diet based on wheat bran (60%),sucrose (12%), salt mixture (2%), yeast(1.3%), lysine (1.23%), methyl paraben(0.13%), vitamin C (0.67%), aureomycine(0.67%), glycerine (150 ml) and distilledwater (150 ml) (for details see 34).Rearing was conduced in plastic boxes(20 × 15 × 10 cm) placed in a rearingroom. The rearing conditions were:temperature of 25 ± 1°C, photoperiod of15: 9 (L: D) and 65 ± 5% relativehumidity.Plant material. E. camaldulensisand E. rudis leaves were collected fromnatural populations at the flowering stageon August 25, 2009 from the arboretumof Korbus (North Tunisia) of the InstitutNational des Recherches en GénieRurale, Eaux et Forêts (INRGREF). Theharvested material was air-dried at roomtemperature (20-25°C) for one week andthen stored in cloth bags.Essential oil extraction andanalysis. The essential oils wereextracted by hydrodistillation of driedplant material (100 g of each sample in500 ml of distilled water) using aClevenger-type apparatus for 4 h. The oilswere dried over anhydrous sodiumTunisian Journal of Plant Protection 202 Vol. 5, No. 2, 2010