【作者】 张丽；

【导师】 范青海；

【作者基本信息】 福建农林大学 ， 植物检疫， 2011， 硕士

【摘要】 厉眼蕈蚊是我国食用菌栽培中的一种重要的双翅目害虫,该类害虫除以幼虫取食多种食用菌和药用菌外,成虫还能传播病害和害螨。在化学防治的弊端日益突显、物理防治还无法有效控制幼虫危害的情况下,生物防治作为一种安全、有效的防治方法,愈来愈成为食用菌害虫防治方法研究的热点。本文研究的目的在于筛选出对食用菌厉眼蕈蚊有效的Bt菌株,确定其主要的杀虫活性成分以及对食用菌的安全性,为将来应用Bt实施食用菌害虫的无害化防治提供科学依据。主要研究结果如下:1. BRC-LLP29和IPS82两个菌株为初筛有效菌株,处理48 h校正死亡率分别达到了87.93%和70.21%。复筛得出处理96 h,BRC-LLP29菌株对厉眼蕈蚊的LC₅₀为1.182×10⁸ cfu/mL,IPS82为1.977×10⁸cfu/mL,说明前者对厉眼蕈蚊的活性高于后者。感染Bt的厉眼蕈蚊幼虫食欲减退,对毛笔触动反应迟钝,有腹泻现象,死亡后虫体变暗,轻触易破。2. BRC-LLP29菌株不同组分杀虫活性不同,低剂量的晶体蛋白（0.02648 mg/mL）对食用菌厉眼蕈蚊具有很高的杀虫毒力,处理后24 h幼虫死亡率达90%,48 h为100%;孢晶混合物也表现出较高的杀虫活性,处理后48 h幼虫死亡率为75%,但是杀虫所需浓度远远高于晶体蛋白;而纯芽孢分离物即使在高浓度下亦几乎无杀虫活性,以26.48 mg/mL的浓度处理后48 h幼虫死亡率仅为8.33%。这说明, BRC-LLP29菌株产生的伴孢晶体蛋白是主要杀虫因子,而芽孢只起辅助杀虫作用。BRC-LLP29晶体蛋白对厉眼蕈蚊7⁸日龄幼虫的LC50为0.004 mg/mL。3. BRC-LLP29发酵液对实验中的8种食用菌菌丝的生长均有不同程度的抑制,抑制作用大小（EC50）依次为香菇（1.175×10⁵）>双孢菇（4.467×10⁵）>茶树菇（1.148×10⁶）>毛木耳（1.318×10⁶）>金针菇（2.512×10⁶）>秀珍菇（3.802×10⁶）>平菇（9.772×10⁶）>杏鲍菇（1.000×10⁷）。4. Bt代谢产物20倍和40倍稀释液在0.05水平上能够显著抑制平菇、双孢菇、香菇、杏鲍菇和金针菇菌丝的生长;Bt代谢产物对双孢菇的抑制作用最明显,稀释320倍后对双孢菇仍有轻微的抑制作用,抑制率为1.83%。相反,Bt代谢产物在稀释320倍的情况下能够显著（p<0.05）促进茶树菇和秀珍菇菌丝的生长,而Bt代谢产物20倍稀释液和40倍稀释液处理的毛木耳菌丝的生长速率分别为3.91和3.71 mm/d,显著（p<0.05）高于对照。综合上述结果,BRC-LLP29菌株发酵液在高浓度下对厉眼蕈蚊幼虫能够起到较好的控制作用,但其作用缓慢,杀虫速度远远比不上吡虫啉、阿维菌素等化学杀虫剂;而且BRC-LLP29菌株发酵液对食用菌菌丝的生长有明显的抑制作用。因此,菇房应用Bt开展食用菌厉眼蕈蚊的无害化防治当需进一步加强应用技术研究。更多还原

【Abstract】 Fungus gnats, Lycoriella sp. （Diptera: Sciaridae）, is one of the important pests in mushroom cultivation. The feeding of sciarid fly larvae causes damage to the cultivation substrates, compost and casing. The adult can also spread fungus diseases and mites. The disadvantages of the chemical control has been increasing and physical prevention can not effectively control damage of the pest. So biological control, as a safe and effective method, is increasingly becoming the focus on preventing and controlling mushroom pests. The purpose of this study is to develop effective Bt strains to Lycoriella sp., determine its main insecticidal activity ingredients and Bt treatment effects on edible fungus hypha growth. And then to improve the scientific basis for Bt prevention mushroom pests in the future. Main results are as follows.1. BRC-LLP29 and IPS82 are effective strains after preliminary screening, the corrected mortality of larvae aged 7⁸ days of Lycoriella sp. was 87.93% and 70.21%, respectively. The concentration-mortality tests of the two strains showed BRC-LLP29 was better than IPS82, and their LC₅₀ was 1.182×10⁸ cfu/mL and 1.977×10⁸ cfu/mL, respectively.2. Low doses of crystal proteins （0.02648 mg/mL） of BRC-LLP29 has higher insecticidal activity, the corrected mortality of larvae aged 7⁸-day-old of Lycoriella sp. was 90% （24 h） and 100% （48 h）; Spore crystal mixture also showed insecticidal activity, the corrected mortality is 75% （48 h） in the concentration of 26.48 mg/mL; Spores of BRC-LLP29 has no insecticidal activity. The crystal protein is the main insecticidal factor, and the LC50 of BRC-LLP29 crystal protein to larvae 7⁸-day-old of Lycoriella sp. is 0.004 mg/mL.3. BRC-LLP29 fermented fluid can inhibit edible fungi hyphae growth, with the increase of concentration, inhibitory effect increased, And inhibitory effect of BRC-LLP29 to 8 kinds of edible fungi （EC50/cfu/mL PDA） is: Lentinus edodes （1.175×10⁵） > Agaricus bisporus （4.467×10⁵） > Agrocybe chaxinggu （1.148×10⁶） > Auricularia polytricha （1.318×10⁶） > Flammulina velutipes （2.512×10⁶） > Pleurotus pulmonarius （3.802×10⁶） > Pleurotus ostreatus （9.772×10⁶） > Pleurotus eryngii （1.000×10⁷）.4. Pleurotus ostreatus, Agaricus bisporus, Lentinus edodes, Pleurotus eryngii, Flammulina velutipes hyphae growth can be significantly （p<0.05） inhibited by metabolites dilutions 20 times and 40 times of BRC-LLP29 strains, Auricularia polytricha hyphae growth can be significantly （p<0.05） promoted in contrast; Agaricus bisporus be severely inhibited even by metabolites dilutions 320 times; BRC-LLP29 metabolites 320 times diluent can significantly （p<0.05） promote hyphae growth of Agrocybe chaxinggu and Pleurotus pulmonarius. Based on the above results, Lycoriella sp. can be controlled by BRC-LLP29 if a higher concentration is used in the laboratory. However, BRC-LLP29 is not as effective as chemicals, and edible fungi hyphae growth can be inhibited. Therefore, it will have great difficulty in applying Bt to control sciarid pests in mushroom cultivation.更多还原