【摘要】 家蚕核型多角体病毒（BmNPV）常规保存在4℃冰箱和室温条件，保存时间对其致病力的影响尚未可知，研究其保存不同时间致病力的变化，可给生产试验提供有效参考。将试验病毒分别配置成浓度1×10⁸PIB/mL、1×10⁷PIB/mL、1×10⁶PIB/mL的悬浊液，采用叶片浸没法添食2龄起蚕，调查对应浓度的家蚕脓病发病头数、存活头数，计算脓病发病率和LC₅₀。以新鲜提取BmNPV的LC₅₀及将其添食家蚕的发病率为参考，评价4℃和室温条件下保存不同时间的BmNPV对2龄起蚕的致病力的影响。结果显示：新鲜提取BmNPV的LC₅₀为2.7×10⁵PIB/mL，该病毒4℃条件下保存30 d、50 d、210 d、360 d后的LC₅₀分别为2.9×10⁵PIB/mL、4.0×10⁵PIB/mL、7.3×10⁵PIB/mL、8.9×10⁶PIB/mL,LC₅₀分别是新鲜提取时的1.07倍、1.48倍、2.70倍、32.96倍；而BmNPV在室温保存30 d、50 d、210 d、360 d后的LC₅₀分别为8.6×10⁵PIB/mL 、2.4×10⁷PIB/mL 、3.7×10⁸PIB/mL、2.1×10¹¹PIB/mL，分别是新鲜提取时的3.19倍、88.89倍、1 370.37倍、777 777.78倍。可见在4℃、室温2种保存温度下，LC₅₀均随保存时间延长而增加，但是室温保存的BmNPV的LC₅₀增加更快。且保存同样时间，室温保存的BmNPV的LC₅₀均明显高于4℃保存，且随保存时间延长，差距越明显。更多还原

【Abstract】 Bombyx mori nucleopolyhedrovirus（BmNPV） is routinely stored at 4℃ or room temperature. However,the effect of storage duration on its pathogenicity remains unclear. Investigating the changes in pathogenicity over different storage periods can provide valuable assistance for production and experimentation. The experimental virus was prepared at concentrations of 1×10⁸ PIB/mL,1 × 10⁷ PIB/mL,and 1 × 10⁶ PIB/mL. Newly molted 2 nd instar larvae of the silkworm strain "932" were inoculated using the leaf-dipping method. The number of diseased larvae with nuclear polyhedrosis and the number of surviving larvae were recorded for each concentration,and the disease incidence and median lethal concentration(LC₅₀)were calculated. Using the incidence and LC₅₀of freshly extracted virus as references,the pathogenicity of BmNPV stored at 4℃ and room temperature for different periods against 2 nd instar larvae was evaluated. The results showed that after storage at 4℃for 30,50,210,and 360 days,the LC₅₀values were 2.9×10⁵ PIB/mL,4.0×10⁵ PIB/mL,7.3×10⁵ PIB/mL,and 8.9 × 10⁶ PIB/mL,respectively. Compared with the LC₅₀of fresh virus（2.7 × 10⁵ PIB/mL）,these values represented an increase of 1.07,1.48,2.70,and 32.96 times,respectively. In contrast,after storage at room temperature for 30,50,210,and 360 days,the LC₅₀values were 8.6×10⁵ PIB/m L,2.4×10⁷ PIB/m L,3.7×10⁸ PIB/mL,and 2.1×10¹¹PIB/mL,respectively. Compared to the LC₅₀of fresh virus,these values increased by 3.19,88.89,1370.37,and 777,777.78 times,respectively. It is evident that under both storage temperatures（4℃ and room temperature）,the LC₅₀increased with prolonged storage time.However,the LC₅₀of BmNPV stored at room temperature increased much more rapidly. Furthermore,for the same storage duration,the LC₅₀of BmNPV stored at room temperature was significantly higher than that stored at 4℃,and this difference became more pronounced with extended storage time.更多还原