IPM approaches for stored date protection in Tunisia: Emphasis on alternative control methods against the date moth Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae)
Abstract: In Tunisia, dates are an important and valuable export commodity, 16% of the total value of agricultural exports coming from the date industry. Moreover, dates presented 6.6% of the total value of agricultural production. Stored dates are subjected to high infestation rates by pyralid moth pests, mainly the carob moth Ectomyelois ceratoniae (Zeller). This devastating pest induced significant economic losses during storage. It caused loss of weight and downgrading of the commercial value of dates. It infested 20% of the harvestable date crop annually. Current available methods for postharvest control are based on fumigation using synthetic fumigants mainly phosphine. However, harmful effects of these chemicals on human health and their side effects on environment, lead to the search of safer and effective alternatives. This paper reported results of several trials conducted using some natural pesticides derived from plants (essential oils), microorganisms (Spinosad) and inert dust (Diatomaceous earth) for the control of different developmental stages of Ectomyelois ceratoniae. Results indicated that these alternatives exhibited ovicidal, larvicidal and adulticidal potentialities against Ectomyelois ceratoniae. The four Eucalyptus essential oils tested (E. camaldulensis, E. leucoxylon, E. dumosa and E. transcontinentalis) displayed strong toxicity against adults and all larval stages. E. transcontinentalis accomplished 100% mortality of Ectomyelois ceratoniae adults after 2 h of exposure at the concentration 143 μl/l air. Additionally, E. leucoxylon oil achieved 100% mortality of fifth instars after 48 h of exposure at the dose 132 μl/l air. On the other hand, spinosad showed an interesting ovicidal activity against Ectomyelois ceratoniae eggs. At the concentration 1ppm, 85% of egg mortality was obtained. Additionally, the use of diatomaceous earth exhibited promising results. No closed eggs were obtained after treating eggs with Protect-It® at the dose of 10 g/kg of dates.