Postharvest control of stored date pests in Tunisia using Eucalyptus essential oils


Abstract: In south Tunisia, dates and its second rate products present a resource for oases andhave a major role in shoring the agriculture and developing regional economy. Nevertheless,dates are prone to many insect pests that cause major economic losses and decrease their quality.The almond moth Ephestia cautella Walker and the Mediterranean flour moth Ephestiakuehniella Zeller are among the most important and destructive insect pests attacking dates instorage in Tunisia. Methyl bromide is used for the control of these insects for postharvesttreatment. However, due to the increasing environmental and human health concerns on theharmful effects of insecticides, the implementation of alternatives effective and friendlier arerequired. These technologies mainly include the use of botanical biopesticide namely, essentialoils. Therefore, this study was undertaken to assess a postharvest treatment against adults of twopyralid moths E. cautella and E. kuehniella using fumigant toxicity of essential oils fromEucalyptus camaldulensus (Dehnh.) and Eucalyptus leucoxylon (F. Muell.).Results showed that fumigant toxicity varied with the oil concentration and the exposuretime. Moreover, E. cautella was more sensitive to the oils than E. kuehniella. For E. camaldulensisessential oil, the LC50 values were 11.07 and 20.46μl/l air, respectively for E. cautellaand E. kuehniella. Regarding E. leucoxylon essential oil, the respective LC50 values were 11.28and 24.59μl/l air for E. cautella and E. kuehniella. In addition for the lowest tested concentration13.16μl/l air, LT50 values were correspondingly 13.49 and 30.46h for E. cautella and E. kuehniellawhen E. camaldulensis essential oil was used whereas respective LT50 values forE. leucoxylon essential oil were 18.01 and 33.29h.Results suggested that E. camaldulensis and E. leucoxylon essential oils could be used as analternative to the synthetic fumigant in postharvest treatment program for the control of storeddate moths.

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