【作者】 张瑞霞；

【导师】 许维岸；

【作者基本信息】 山东农业大学 ， 农业昆虫与害虫防治， 2004， 硕士

【摘要】 蚜虫病原真菌是指虫霉目真菌中侵染蚜虫的病原菌的总称。隶属于接合菌亚门，接合菌纲。虫霉目真菌具有主动弹射分生孢子的特性，并能在适当的自然条件下引发害虫流行病，对害虫种群有重要的自然控制作用。新蚜虫疠霉、诺氏虫疠霉和块耳霉都是田间常见的蚜虫病原真菌，易引发蚜虫种群流行病，是蚜虫最重要的自然控制因子之一。本文对泰安郊区麦田和蔬菜田蚜虫病原真菌的侵染和流行动态进行系统调查。主要对优势种新蚜虫疠霉菌株的生物学特性进行研究，并对诺氏虫疠霉和块耳霉菌株进行部分研究，主要研究内容和结果如下： 1．系统的调查并研究了麦蚜和菜蚜上蚜虫病原真菌的流行动态，发现蚜虫病原真菌的侵染高峰略滞后于蚜虫种群高峰，在后期控制蚜虫效果比较明显。蚜虫病原真菌一般停留在“低频、常发、局部性”的地方病状态下，但也有个别地块形成一定的流行病，可在短时间内将蚜虫种群控制在低密度状态。温室内的湿度和温度适宜蚜虫病原真菌的侵染和流行，侵染率较田间蚜虫病原真菌的侵染率高，能够对蚜虫起到有效的控制作用。麦蚜和菜蚜最重要的天敌是蚜虫病原真菌和蚜茧蜂。蚜虫病原真菌开始侵染麦蚜的时间较晚，导致病原真菌在麦田流行和发挥控蚜作用的时间较短。因此，病原真菌的侵染率略低于蚜茧蜂的寄生率。蔬菜田病原真菌的侵染率相对高于蚜茧蜂的寄生率。泰安郊区麦田的蚜虫病原真菌有新蚜虫疠霉、诺氏虫疠霉、普朗肯虫霉和耳霉；蔬菜田蚜虫病原真菌的种类主要有：新蚜虫疠霉、诺氏虫疠霉、根虫瘟霉、耳霉及弗氏新接霉。通过调查发现新蚜虫疠霉始终是麦蚜和菜蚜的主要病原真菌，在麦田、温室大棚和整个蔬菜生长季节蚜虫病原真菌的侵染和流行中都占有非常重要的地位，常与诺氏虫疠霉混合侵染蚜虫种群，成为麦蚜和菜蚜种群的重要自然控制因子之一。 有翅蚜的活动性较强，能够携带病原真菌在当地或异地进行传播和扩散，对于蚜虫病原真菌的传播与流行起到重要的媒介作用。 2．本文针对优势种新蚜虫疠霉菌株进行生物学特性研究。主要包括温度、湿度对新蚜虫疠霉孢子萌发的影响和温湿组合对蚜尸产孢的影响。实验结果表明：新蚜虫疠霉虫尸产孢和孢子萌发对湿度条件的要求极为严蚜虫病原真菌生物学及流行学特性的研究格。其抱子在RH=95%时不能萌发，RH=97.5%时萌发率较低，咫王=10既时抱子萌发率最高;在95%的湿度条件下新蚜虫病霉不能形成分生抱子，RH=97.5%时产饱量较少，100%湿度或自由水存在的条件下产抱量最大。新蚜虫病霉抱子萌发的最适宜温度是巧℃一20℃。RH=100%时新蚜虫病霉产抱的温度范围较广，10℃一25℃之间均能产生分生抱子，30℃的高温下不能产抱。以10℃产抱数量最大，产抱持续的时间最长，25℃次之，20℃下产抱量最低。一般来说，随着温度的升高，产抱持续的时间缩短，产抱高峰前移，即产抱的速度加快。 另外，还研究温度对诺氏虫病霉和块耳霉袍子萌发的影响。其结果显示:温度对诺氏虫病霉和新蚜虫病霉的影响相似，无显著差异。诺氏虫病霉抱子萌发的最适宜温度在巧℃一20℃，在30℃以上的高温条件下抱子失去活性，不能萌发。块耳霉的抱子萌发速率较快，适合抱子萌发的温度范围相对较广，温度在15℃一35℃之间24h内抱子全部萌发。 3.通过测定10种田间常用杀菌剂对新蚜虫病霉、诺氏虫病霉和块耳霉抱子萌发的影响，研究了杀菌剂与蚜虫病原真菌的相容性。结果表明:多数杀菌剂对蚜虫病原真菌的影响较大，有的严重抑制真菌抱子萌发，且与有效成分的浓度成正比，浓度愈高，抑制作用愈大。少数杀菌剂与病原真菌的相容性较好。例如普力克与新蚜虫病霉相容性较好，多菌灵、普力克与块耳霉有良好的的相容性。经过对上述三种病原真菌进行比较，诺氏虫病霉对杀菌剂最为敏感，新蚜虫疡霉次之，而块耳霉的耐药性相对较强。本次研究证明，在蚜虫病原真菌自然流行期间不宜喷洒高浓度的杀菌剂。然而在次亚致死浓度下，普力克、施佳乐2种杀菌剂却能够在一定程度上促进新蚜虫病霉和诺氏虫病霉抱子萌发，但其机理目前不详。更多还原

【Abstract】 The aphidopathogenous fungi are referred to the spieces of Entomoph-thorales which infect aphids. They belong to Zygomycota and Zygomycetes. The Entomophthorales can eject spores actively and then cause epidemic disease under suitable climate condition. They can infect many kinds of insects and become the most important biological control agents. Aphidopathogenous fungi, for example. Pandora neoaphidis Humber, Pandora nouryi Humber and Conidiobolus thromboides Drechsler are all easily found in natural fields. Because they can often cause aphid epizootics, they play the most important role in the regulation of aphid population. A systematic investigation of the dynamics of aphidopathogenous fungi was made in wheat and vegetable fields in Taian. This article reported detailed studies on the biological and epizootiological characteristics of the strain P. neoaphidis. We also made partial studies on the strains of P. nouryi and C. thromboides. The main results were as follows.1. The paper presented systematic investigation in the dynamics of the aphidopathogenous fungi on wheat aphids and peach aphids. The infection peak of aphidopathogenous fungi were found to stay behind the peak of aphid population and the aphidopathogenous fungi usually controlled the aphids population effectively at late stage of growing seasons.The aphidopathogenous fungi often became as enzootic. But epizootic could form in several fields and kept the aphids in check at low level of population density during a short period. The trial indicated that the temperature and relative humidity in greenhouse is suitable for the epidemic of aphidopathogenous fungi, and the infection rate was higher than that in fields. Therefor, these fungi could effectively control the aphid population. The most important natural enemiesof wheat aphids and peach aphids were aphidopathogenous fungi and aphid parasitoids. The aphidopathogenous fungi infected the aphids at late period in 2003, so they began to prevalent later and could not effectively control the aphid population. Therefor, the infection rate of aphidopathogenous fungi was lower than the parasitism rate of aphid parasitoids in wheat fields. But the results were quite different in vegetable fields. On the outskirt of Taian, the main species of aphidopathogenous fungi in wheat fields were P. neoaphidis, P. nouryi, Entomophthora planchonianah and Conidiobolus.spp. In vegetable fields, the main species were P. neoaphidis, P. nouryi, Neozygites fresenii, Zoophthora randicans and Conidiobolus.spp. The result of research showed that P. neoaphidis was the most important species of aphidopathogenous fungi. P. neoaphidis played an important role in the prevalence of aphidopathogenous fungi in wheat fields, greenhouses and vegetable fields. P. neoaphidis always infected aphids accompanied with P. nouryi and became the most important biological agent in the control of wheat aphids and peach aphids.Pterygotous adults was more active than apterous adults, and they could carry entomopathogenic fungi spreading to the other places.2. This article made detailed studies on the biological characteristics of the strain P. neoaphidis, including the feature of conidia production and conidia germination at range of varying temperature and humidity. It was proved that the conidia production and conidia germination of P. neoaphidis needed strict humidity. Therefore, it was considered that the most favorable conditions were in the saturated atmosphere. At the condition of RH=95%, the conidia could not germinate and P. neoaphidis could not eject conidia as well. When the relative humidity rose to 97.5%, P. neoaphidis could product little conidia and the conidia could germinate to some extent. When RH=100%, the conidia germinated well and the conidia production were abundant. The most favorable temperature for conidia germination was 15 C-20 C . When RH=100%, the strain P. neoaphidis could release conidia at 10C~25C, but no conidia were released at 30C. The greatest number of conidia was formed at10C, and the next was at 25 C更多还原