Modeling heat transfer for disinfestation and control of insects (larvae and eggs) in date fruits

A space-and-time dependent model describing the impact of heat transfer on insect survival rate was developed for analyzing the heat disinfestation process of dates. A 2D axial-symmetric domain was defined with five sub-domains: the bulk date pulp, a thin air layer and the date pit, a larva (located in the air layer) and eggs (on the date surface). The model included convective heating and microwave heating (915 MHz). Dielectric properties of the date pulp, egg and larvae were measured. The model predictions showed good agreement with experimental results in the case of the “biological model” (Ephestia kuehniella Zeller) in dates subjected to hot air treatment (70 °C). Sensitive analysis showed that the date size and water content greatly affected the heating time process, during hot air and microwave treatments. Moreover, regarding the eggs’ specific surface, it is advisable to combine convective hot air with microwave heating to induce egg mortality on the date surface.

► Analysis the dynamic of insect mortality during heat disinfestation process of date.
► A model including heat (microwave, air convective) and insect mortalities was developed.
► Loss factor (915 MHz) of the date pulp, egg and larvae were found to be, 7.9, 8.1 and 19.4.
► Controlling egg mortality on the date surface need convective hot air with microwave.
► Convective with microwave heating is a good strategy for disinfestation date fruits.