Efficacy of Eucalyptus essential oils fumigant control against Ectomyelois ceratoniae (Lepidoptera: Pyralidae) under various space occupation conditions Jouda Mediouni Ben Jemâa a, * , Soumaya Haouel a , Mohamed Larbi Khouja b a Laboratoire de Biotechnologie Appliquée à l’Agriculture, INRAT, Rue Hedi Karray, 2080 Ariana, Université de Carthage, Tunis, Tunisia b Laboratoire d’Ecologie et d’Amélioration Sylvo-Pastorale, INRGREF, Rue Hedi Karray, 2080 Ariana, Université de Carthage, Tunisia article info Article history: Accepted 25 February 2013 Keywords: Eucalyptus spp. Essential oil Fumigation Space occupation Stored dates Moth Tunisia abstract In this work, Eucalyptus camaldulensis and Eucalyptus leucoxylon essential oils were analysed and tested for their fumigant toxicity against adults and last instar larvae of the carob moth Ectomyelois ceratoniae. The effectiveness of the essential oil fumigations against last instar larvae was investigated in an empty space and with 10%, 50%, 75% and 100% spaces occupied with dates. Results showed that larval mortality varied according to the species of Eucalyptus, exposure time and percentage of space occupation with dates. For both oils, high mortalities were obtained after 10 days of exposure and with spaces less occupied with dates (100% mortality with empty space). Fumigation in space 10% occupied with dates was totally effective with E. camaldulensis essential oil, while for E. leucoxylon oil, 94.5% and 98.4% mortally were obtained after respectively 3 and 7 days of exposure. In space 50% occupied with dates, mortality of E. ceratoniae larvae was 93.9% with E. camaldulensis oil against 90.8% with E. leucoxylon oil after 10 days of exposure. In space 100% filled with dates, after 7 and 10 days of exposure to the oils mortality fell to respectively 66.6 and 86.6% for E. camaldulensis and 62.4 and 80.3% for E. leucoxylon. Our work clearly shows the importance of the amount of space occupancy in considering use of Eucalyptus essential oils for postharvest control of the carob moth. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction In Tunisia, dates and their secondary products are the main agricultural products of the oases having a major role in local economy (Mediouni Ben Jemâa et al., 2012a). Oases cover almost 40,000 ha and represent an original form of human development in very harsh climatic conditions (Genin et al., 2006). Tunisia is currently the tenth largest world producer and the foremost exporter of dates in terms of value (Besbes et al., 2009). The annual national production is around 174,000 tonnes with a growing rate, including 79,200 tonnes for export (GIFruits, 2009). The carob moth, Ectomyelois ceratoniae (Zeller, 1881) (Lepidop- tera: Pyralidae) is one of the main pest insects attacking dates in storage in Tunisia (Mediouni et al., 2004). This pest infests 20% of the harvestable date crop annually (GIFruits, 2009). This polypha- gous species attacks several other host plants stored locally such as pomegranate, almond and pistachio nut (Dhouibi, 1989) and causes major economic losses in the Mediterranean basin and Near East regions (Al-Izzi et al., 1985). Measures of stored pest control are mainly based on application of synthetic insecticides and fumigants. Methyl bromide is still used in post-harvest insect control for dates in Tunisia (Mediouni Ben Jemâa et al., 2012a). However, the use of this pesticide is to be phased out due to human and environmental concerns (Bell, 2000). Recently, natural pest control methods including essential oils have been increasingly explored (Batish et al., 2008). Essential oils exhibit a wide spectrum of biological activity including anti- microbial, fungicidal, insecticidal/insect repellent, herbicidal, acar- icidal and nematicidal properties (Prabuseenivasan et al., 2006; Batish et al., 2008). Previous studies reported the fumigant toxicity of essential oils from various Eucalyptus species against different developmental stages of carob moth: Eucalyptus rudis (Endl.) against adults (Haouel et al., 2010), Eucalyptus transcontinentalis (Maiden) and Eucalyptus dumosa (A. Cunn. ex J. Oxley) against eggs, larvae and adults (Khemira, 2012) and Eucalyptus camaldulensis (Dehnh.), Eucalyptus astringens (Maiden), Eucalyptus leucoxylon (F. Muell.), Eucalyptus lehmannii ((Schauer) Benth.) and E. rudis against adults (Mediouni Ben Jemâa et al., 2012b). On the other hand, the successful implementation of essential oils as fumigants is hampered by the relatively high concentrations needed for the * Corresponding author. Tel.: þ216 71235317, þ216 97 652 174 (cell); fax: þ216 71752897. E-mail addresses: joudamediouni@lycos.com, j_mediouni@hotmail.fr (J. Mediouni Ben Jemâa). Contents lists available at SciVerse ScienceDirect Journal of Stored Products Research journal homepage: www.elsevier.com/locate/jspr 0022-474X/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jspr.2013.02.007 Journal of Stored Products Research 53 (2013) 67e71