| Up to now there is still no generalized risk analysis protocol for the import and release of exotic biological control agents internationally. Conventional screening protocol for biocontrol agents usually results in poor predication because of lack investigation of phylogeny among biocontrol agents and its hosts, ecological adaptability, heredity, host selecting behavior and bioclimate correlation analysis. In order to overcome the insufficient screening test current used for exotic biocontrol agent, we made a risk analysis for Epiblema strenuana as a case study. E. strenuana is an important biocontrol agent against ragweed (Ambrosia artemisiifolid) and Parthenium hysterophorus. This phytophagous insect was introduced to China as a potential candidate to control A. artemissifolia by Chinese Academy of Agricultural Sciences in 1990. Safety to flora in northern region of China was a consideration and it was not released until in 1993 on a small scale in Linxiang, Hunan province, China. However, risk analysis and monitoring was not conducted after its release. In our studies, risk constraint factors analyzed were focused on phylogeny, host specificity, bioclimate adaptability, interspecific niche and control efficiency on target weeds. A methodology for risk analysis of E. strenuana in biological control of weeds as a model was obtained, and also the safety of E. strenuana and its ecological impact were further verified after its released since 1993.1. Host specificity test: Thirty-six species of economic, ornamental plants and weeds belonging to nine families were selected based on the centrifugal phylogenetic testing method. A no-choice test was conducted to evaluate E. strenuana larva feeding risk at laboratory, by inoculating different instar larvae on the tested plants. A more realistic multiple-choice test was conducted for three successive generations to evaluate its selection risks in open field in three scenarios: (1) adult oviposition, (2) larva development, and (3) larval movement capacity.Based on the probability theory, risks were analyzed in two ways. (1) Single Exposure Factor Risk Index (SEFRI) was introduced to quantitatively evaluate selection risk of E. strenuana to the tested plants. SEFRI for larvae development and adult oviposition was divided into three categories: active selection risk (SEFRI > 0.01), random selection risk (SEFRI < 0.01) and no selection risk (SEFRI = 0). (2) Risk Index (RI) was used to analyze its combined exposure factor risk on a tested plant, i.e. RI = SEFRI(1) X SEFRI(2). X SEFRI(n).Laboratory no-choice feeding test showed that of all 36 species tested, E. strenuana could complete development only on A. artemisiifolia and Xanthium sibiricum. When inoculating larvae on tested plants, all young larvae (1-3 instar) died;and only a very few old larvae (4-6 instar) could develop to pupae on Artemisia annua, Dendranthema morifolium (cv. Yellow lotus) and Helianthus annuus without any feeding. The development on these plants was a false phenomenon.Open field multiple-choice test showed that in the all 16 tested plants, including A. artetnisiifolia, X. sibiricum, 6 cultivars of H. annuus and 7 species/ cultivars of potted chrysanthemum, Single Exposure Factor Risk Index (SEFRI (1)) for adult oviposition from three generations was 0.76-1 on A. artemisiifolia, 0-1 on X. sibiricum, 0-0.06 on A. annua and 0-0.02 on T. erecta, only 0-0.004 on H. annuus (I-M1 and I-M2), and 0 on other tested plants. SEFRI (2) for larval survival of E. Strenuana was 1 on A. artemisiifolia and 0.42 on X. sibiricum, and 0 on other tested plants. SEFRI (3) for capability of larval selection for tested plants in non-choice condition was 1 on A. artemisiifolia, 0.59 on X. Sibiricum, 0.21 on A. annua, 0 on Helichrysum bracteatum and 0.03-0. 15 on other tested plants. Thus, the combined host specificity Risk Index (RT) was 0.76 for A. artemisiifolia and 0.25 for X. Sibiricum (active selection risk), and 0 for the other tested plants (no selection risk), respectively. The population incr...
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