Temperature-Dependent Biological Control Effectiveness of Tamarixia Radiata (Hymenoptera: Eulophidea) Under Laboratory Conditions

Abstract

The parasitism rate and host-feeding rate of Tamarixia radiata (Hymenoptera: Eulophidae), an ectoparasitoid of Diaphorina citri (Hemiptera: Liviidae), were evaluated at 20, 275, 30, and 35 degrees C, at 70 +/- 5% RH, and 14 h of photo-period. The biological control efficacy of T radiata was evaluated by linking the age-stage predation rate with the two-sex life table. The net host-feeding rate (C-0) by T radiata was 32.05, 54.40, 17.25, and 1.92 nymphs per female parasitoid at 20, 27.5, 30, and 35 degrees C, respectively.The total net nymphs killing rate (Z(0)) was 103.02, 223.82, 72.95, and 6.60 nymphs per female parasitoid at 20, 27.5, 30, and 35 degrees C, respectively. Noneffective parasitism rate was observed at 35 degrees C because of high mortality at this temperature. Our results indicated that temperature had meaningful effects on parasitism and host-feeding rate parameters in the laboratory, and may affect biological control efficiency of the parasitoid in the field. The highest host-feeding rate and total biological control efficiency of T radiata were recorded at 27.5 degrees C. Most importantly, we found that host-feeding activity of the parasitoid is temperature-dependent, and changed across temperature regimes: the host-feeding rate increased as the temperature increased up to 30 degrees C, started to decrease after this temperature and declined to its minimum level at 35 degrees C. This information is valuable for developing biological control and integrated pest management techniques for Asian citrus psyllid management.