【作者】 杨云强；

【导师】 姜述君；

【作者基本信息】 黑龙江八一农垦大学 ， 植物病理学， 2009， 硕士

【摘要】 黑龙江省作为我国的主要大豆生产基地,在发展以大豆为原料的绿色有机食品的生产方面有着得天独厚的优势,并已成为黑龙江省农业生产发展的一个重要方向。如何减少化学农药向农业生态系统的输入是当前黑龙江省发展绿色有机大豆生产中的一个亟待解决的问题,而开发生物除草剂可以说是一条有效的途径之一。反枝苋(Amaranthus retroflexus Linn.)和稗草(Echinochloa crusgalli Linn.)是世界性恶性杂草,也是黑龙江省大豆田的主要杂草。因此,本研究针对这两种杂草,开展微生物除草剂菌株筛选、菌株生物学特性、生物安全性评价及微生物除草剂水乳剂开发和微生物除草剂复配剂的研究。结论如下:1.从50种病原真菌中筛选出2个生防菌Alternaria.alternata和A.amaranthi-3。Alternaria.alternata和A.amaranthi-3分别对稗草和反枝苋有较强的致病作用。这两个菌株对大豆、玉米、水稻等作物安全。拮抗试验表明,A.alternata菌株和A.amaranthi-3菌株无明显的拮抗作用。2.3%的葡萄糖能够显著促进A.alternata和A.amaranthi-3菌株孢子的萌发。pH值和温度对A.alternata和A.amaranthi-3菌株孢子的萌发率均有显著差异。A.alternata和A.amaranthi-3菌株孢子的萌发的最适pH值是7,最适温度是26~28℃。光照条件对A.alternata和A.amaranthi-3菌株孢子的萌发影响不显著。3.接种浓度显著影响菌株的致病力,两种生防菌的致病力随孢子浓度增加而增大,当接种浓度达到107个孢子/mL时,对反枝苋、稗草幼苗生长抑制率达到87.96%,极显著高于其它低浓度处理(P<0.01)。两种生防菌受露期影响较大,其防效随露期的延长而增强,不保湿的条件下两种生防菌对反枝苋、稗草幼苗生长抑制率为28.65%,保湿条件增加到48h后,对杂草的生长抑制率也提高到82.27%。4菌剂剂型试验结果表明,在供试的油剂中,大豆油较适合作为水乳剂的喷洒介质。确定了Span 80:Tween 80=1:3作为最佳复配乳化剂。盆栽试验表明,A.amaranthi-3水乳剂在不保湿情况下,对反枝苋生长的抑制率达到88.35%。生防菌混合接种试验表明,在不保湿情况下,复合水乳剂对反枝苋、稗草混合杂草生长的抑制率达到89.15%,水剂为28.65。这表明水乳剂显著减少了菌株对露期依赖,并显著提高了菌株的致病力。5.复合菌剂与低浓度除草剂复配可以提高对反枝苋和稗草的控制效果。分生孢子浓度为104个孢子/mL复合菌剂中加入10%化学除草剂15%氟·精乳油,盆栽试验结果表明,制剂对反枝苋和稗草防效达到95.56%。当浓度增加到108个孢子/mL时,防效为97.35%。这表明菌剂与除草剂混合可以降低生防菌的孢子使用浓度和除草剂的用量。更多还原

【Abstract】 Heilongjiang Province is the main soybean growing region in China. It has a unique advantage in Green Food products which soybeans are used as raw materials. Therefore Organic agriculture has become an important development direction in Heilongjiang Province.It is an urgent issue about how to reduce chemical pesticide to enter the agro-ecosystem in the current development of green organic soybean industry. Biocontrol would appear to be the perfect solution for weed control in organic agriculture..Both Amaranthus retroflexus and Echinochloa crusgalli, as the worldwide malignant weeds, are the main weeds in soybean field in Heilongjiang Province. Therefore, for control Amaranthus retroflexus and Echinochloa crusgalli, the studys on screening mycoherbicide, biological characteristics of strains.bio-safety evaluation and multiple-strains mycoherbicide were carried out in the paper.The results are as follows:1.Alternaria.alternata and A.amaranthi-3 show a better potential as mycoherbicidel agents in 50 pathogenic fungi. A.alternata and A.amaranthi-3 strains have highly pathogenic to A. retroflexus and E.crusgalli, respectively. Soybeans,corn and rice were not Susceptible to the two mycoherbicidel agents. The result of Antagonist experiment showed that there were not significant antagonistic effect between A.alternata and A.amaranthi-3 strains.2.Glucose can promote spore germination of A.alternata and A.amaranthi-3 strains at 3% concentration. The pH value and temperature have a significant impact on the spore germination of A.alternata and A.amaranthi-3 strain. A.alternata and A.amaranthi-3 strains of spore germination The optimum pH value is 7 for spore germination of the two mycoherbicidel agents. The optimum temperature is 26~28℃. The spores germination was not impacted by illumination conditions.3.The results showed that the severity of disease was dependent on the density of spores applied. The inhibiton of biocontrol agents on seedlings growth of A.retroflexus and E.crusgalli reached 87.96% at concertration of 107 spores/mL. In addition,dew period have a strong impact on the pathogenicity of two biocontrol agents. The disease severity enhanced with extending dew period. In no moisture conditions, growth inhibition rate of biocontrol agents on weed seedlings was 28.65%. An exposure of 48 h at dew period led to the highest growth inhibition rate(82.27%).4. Soybean oil may be used as spray the medium in the emulsion system. Span 80/Tween 80(1:3)is best the emulsifier. In the absence of dew, the biocontrol potential of the emultion to A. retroflexus reached 88.35%. The results of biocontrol agents mixture experiment showed that multiple-Strains mycoherbicide formulated in the oil emulsion produced 89.15% growth inhibition of A.retroflexus and E.crusgalli more than 28.65% of mycoherbicide formulated in aqueous Tween solution n the absence of dew. The results indicated that emulsion can reduce the effect of dew period to mycoherbicide.5.Multiple-strains mycoherbicide combined with low dosage of herbicides can improve the control efficacy of multiple-strains mycoherbicide to weed. when multiple-strains mycoherbicide spores (104 spores/mL) mix with 10% herbicides, the results of pot test showed that the control efficacy of the formulation to A.retroflexus and E.crusgalli reached 95.56%, and spores applied at 108 spore/mL produced a control efficacy at 97.35%. The results indicated that mycoherbicide mix with herbicide can reduce the use dosage of mycoherbicide agents and herbicide.更多还原