摘要
河南省驻马店地区属我国粘虫一代常发区,根据1975—1989年上蔡县和新蔡县的田间多点调查,证明中华卵索线虫是粘虫幼虫的重要寄生天敌。粘虫幼虫感染中华卵索线虫的途径是通过感染期线虫钻入体内,而非通过吞食线虫卵。其感染方式是粘虫幼虫潜土时被线虫感染;尚无试验结果表明中华卵索线虫感染期幼虫能爬上植株去寻找宿主。在18—20℃和22—27℃室温下,线虫幼虫在宿主体腔内营寄生生活8—14d后钻出体外,宿主就死亡。线虫寄生率等于宿主死亡率。被寄生的粘虫幼虫食叶量平均减少38%。中华卵索线虫对粘虫的自然控制作用表现在三方面:(1)能常年有效地降低一代粘虫的种群数量。在15年中58%的调查点,该线虫对粘虫的寄生率达40%以上,最高超过90%。(2)粘虫幼虫被寄生后,食叶量显著减少,一般在5—6龄暴食期前死去,减轻了对农作物的为害。(3)有效降低一代粘虫的种群数量以后,也就降低了二代粘虫常发区的迁入虫源基数。在同年同地的不同田块中,4月份经过越冬的线虫不同密度,是影响5月份对粘虫寄生率差异的主要因子。在同一地点的不同年份,影响寄生率变动的主要因子是当年4月下旬至5月中旬的降雨日,降水量和相对湿度。
The first generation armyworm, Mythimna separata, commonly occur in Zhu Ma Dian Prefecture, Henan Province in Central China. Field studies during 1975—1989 in Shangcai County and Xineai County of the prefecture confirmed that Ovomermis sinensis is an important parasitic natural enemy of the armyworm. The mode of infection is that the infective juveniles of O. sinensis penetrate the larva of armyworm with the help of a mouth stylet and settle in the body cavity, when the noctuid host touches the soil. No trial result indicates the infective juveniles can move up plants to infect hosts, and no host is infected by eating the eggs of parasite. Feeding capacity of the infected larvae of armyworm reduced by 38% in average. In the laboratory urder the conditions of 18—20℃ and 22—27℃, the infected larvae died in 14 and 8 days, respectively, after infection. During an outbreak of the armyworm in 1984, when the larval population density was 30.3—119.5 larvae/m^2 in wheat fields of Dongan Village, Shangcai County, the natural larval parasitization by the nematode was 35—45.5%. The defoliation of wheat was minimal with no pesticide application. The natural con trol effects of O. sinensis are shown in three aspects. (1) The average parasitization rate was over 40% with the highest reaching 90%, in 58% of the observation sites in 15 years. The mermithid parasite thus can effectively decrease the first generation population of host armyworm. (2) The infected larvae of armyworm reduce their feeding capacity, and most of them died before 5—6 instar, so the amount of destruction decreases considerably. (3) Results of a data analysis for 1979—1985 revealed a significant negative corelation between the natural parasititztion of the pest in its first generation occurring area (e. g. Xincai County) and the number of trapped adults in its second generation ocurring area(Jinzhou, Gongzhuling, Harbin of northeast China). It indicated that suppression of the first generation armyworm population by conservation of the nematode may contribute to reduction of the initial population level of the migratory armyworm. In Zhu Ma Dian area, the overwitering density of mermithid adults in early spring, number of raining days, precipitation rate and relative humidity during late April to mid May were found to be the main factors influencing the fluctuation of armyworm parasitization. It had successful practices by using the mermithid parasite O. sinensis as an biocontrol agent of armyworm in wheat fields.
出处
《武夷科学》
1992年第1期249-260,共12页
Wuyi Science Journal
基金
全国粘虫综合防治研究协作组
农业部全国植物保护总站的资助
中国农业科学院院长基金
黄淮海中低产地区开发基金
关键词
索科线虫
中华卵索线虫
粘虫
寄生过程
自然控制
Mermithidae, Ovomermis sinensis, Mythimna separata, Infection process, Natural control
