ABSTRACT Cephalonomia tarsalis Ashmead (Hymenoptera: Bethylidae) is a parasitoid of the Saw-toothed beetle Oryzaephilus surinamensis Linnaeus (Coleoptera: Silvanidae) larvae. This investigation aimed to establish ecological indicators and identify optimal release conditions for this parasitoid. For the experiments, three glass boxes measuring 40 x 50 x 50 cm were prepared. Each box was filled with 12 kg of Sayer cultivar dates. Subsequently, 500 saw-toothed beetle larvae were introduced, followed by the release of 50 parasitoid wasps one day later, with a sex ratio of 1:1. Average effective parasitoid population density (PSC), host (HSC) and parasitism percentage (%P) were calculated. Time series models of host and parasitoid population density fluctuations were evaluated by the cross-correlation index. The results indicate that the percentage of parasitism exhibited three distinct fluctuation periods: the first to seventh weeks, the eighth to fourteenth weeks, and the fifteenth week to the end of the season. The highest level of parasitism occurred in the 16th week of the third period. The correlation of larval population density increased from the first to the fifth week and from the seventh week to the end of the period, displaying a decreasing and weak trend with minor fluctuations. The highest rate of fluctuations in the parasitoid wasp population occurred in the second week. The maximum probability rate of non-establishment of the parasitoid in the larval population was zero throughout the entire period. These findings contribute to the information required for the advancement of biological control methods targeting O. surinamensis in date fruit storage using C. tarsalis.
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