摘要
在 1 5℃与 1 0 0 % RH的组合条件下以接种安徽虫瘟霉 (Zoophthora anhuiensis)和未接种的桃蚜 (Myzus persicae)成蚜按不同比例混合 (0∶ 6、1∶ 5、2∶ 4、3∶ 3、4∶ 2、5∶ 1及 6∶ 0 )建立蚜群 ,3次重复 ,考察流行病的发生与发展。结果表明 ,在带菌蚜 5 0 %以上的蚜群中 ,活蚜的数量增长因高强度的流行病发生而得到有效控制 ,活蚜数始终未超过 5 0头 /90cm2 ,第 2 2天观察结束时与对照 (0∶ 6)蚜群的 65 6头 /90 cm2 相比控蚜效果高达 93 .2 4%～ 1 0 0 %。在接菌与未接菌比例1∶ 5和 2∶ 4的蚜群中 ,蚜病的发生虽未能充分控制蚜虫的数量增长 ,但结束时的蚜虫数量均显著低于对照 ,分别为 3 5 6头 /90 cm2和 2 0 7头 /90 cm2 ,控蚜效果亦分别达 46%和 68%。各处理蚜群中病害流行随时间的变化很好地拟合 Gompertz模型 (r2 =0 .97) ,由此估计出安徽虫瘟霉不同初始菌量在蚜群中的流行速度 (R)及最高流行水平 (K )。线性回归分析表明 ,初始侵染体密度确定了 R (r2 =0 .89)和 K (r2 =0 .90 )估计值的 90 %变异 ,充分显示安徽虫瘟霉流行病的发生及流行强度对初始侵染体和寄主密度的依赖性。
In an attempt to evaluate the impact of initial inocula and host density on the development of the epizootic of the green peach aphid, Myzus persicae (Sulzer), caused by the entomophthoraceous fungus, Zoophthora anhuiensis (Li) Humber, 6-aptera colonies were initiated with each including different number of inoculated and uninoculated apterous adults (ratios: 0∶6, 1∶5, 2∶4, 3∶3, 4∶2, 5∶1, and 6∶0) and then were allowed freely for reproduction,fungal infection and mycosis dissemination at the optimal regime of 15℃ and 100% RH. High levels of epizootic occurred in the colonies initiated with ≥50% apterae inoculated. The density of living aphids (apterae and their offspring) in the colonies never exceeded 50 aphids per 90 cm 2 during a 22-day period of observation, and was 93%～100% lower than 656 aphids per 90 cm 2 in the control (0∶6). In the colonies initiated with fewer apterae inoculated (1∶5 and 2∶4), the aphid density decreased by 46%～68% (356 and 207 aphids per 90 cm 2) compared to that in the control though the epizootic was insufficient to suppress the increase of aphid colonies. The development of fungal epizootic in each of the colonies was well described using a modified Gompertz model (r 2=0.97), which is usually used for modeling plant epidemic. The initial proportion of apterae inoculated in the colonies was highly correlated to R (r 2=0.89) and K (r 2=0.90), the apparent infection rate and the capacity of epizootic estimated from fitting the model. This indicates that fungal inocula and host density are highly important for the development of M. persicae epizootic induced by Z. anhuiensis.
出处
《生态学报》
CAS
CSCD
北大核心
2001年第10期1607-1612,共6页
Acta Ecologica Sinica
基金
国家杰出青年科学基金 (3 95 2 5 0 0 4)
国家自然科学基金 (3 9870 5 1 3
3 9770 0 1 6)
关键词
安徽
虫瘟霉
桃蚜
初始侵染体
寄主密度
流行模型
流行病
Zoophthora anhuiensis
Myzus persicae
initial inocula
host density
epizootic modeling
