拮抗菌防治西瓜枯萎病的试验

从西瓜、黄瓜、柑桔等作物根际中分离到的B11等芽孢杆菌的哈茨木霉T31、粘帚霉G1等拮抗真菌，对防治西瓜枯萎病菌有一定抑制作用。经田间防治试验，T31、G1和B11单个菌的田间防效在35％－50％左右；施用T31、G1、B11的混合拮抗菌和采取的一些措施（有机肥作基肥，拮抗菌与杀菌霸混施）对西瓜枯萎病有更好的防治作用，防效达60％－85％。     

西瓜枯萎病病原菌生长特性的研究

西瓜枯萎病是西瓜的主要病害之一,其病原是镰刀菌(Fusarium oxysporum f.sp.Melonis),本实验从温度和pH值两方面对该菌菌丝的生长影响进行了研究,结果表明该病原菌在20～34℃下均能生长,在28～30℃之间生长较好;在pH 4.04～10.89之间均可生长,其最适合的pH值为6.08～8.20,说明该菌的适应性较广。     

柱花草炭疽病菌的鉴定及生物学特性研究

对柱花草炭疽病菌的鉴定及生物学特性测定结果表明：柱花草炭疽病菌为盘长孢状刺盘孢菌[Colletotrichumgloeosporioides（Penz）Sacc]．病菌生长温度15～36℃;适宜生长温度25～30℃;分生孢子萌发的温度6～40℃,最适萌发温度为28℃;分生孢子在饱和湿度下萌发率为83．1％,在饱和湿度加水滴中达87．9％;分生孢子的致死温度为49℃10min;病菌生长的pH值是2．5～14．0,最适pH值为6．4～7．2;病菌对碳源的利用较氮源好。     

红脂大小蠹生物学特性及防治方法

红脂大小蠹在吕梁地区一年发生两代，主要以老熟幼虫和成虫在油松根部越冬。也有以蛹越冬现象。该虫主要危害油松主干和根部，另外还发现危害华北落叶松，严重影响林木生长，并导致树木成片死亡。防治上可采用清理林地、铒木诱杀、代桩诱虫、挖树根、人工诱捕、生物防治、化学防治等方法来降低虫口密度。     

蚬木曲脉木虱的生物学特性及室内药效试验

蚬木曲脉木虱经鉴定为一新种。此害虫常以若虫群集于嫩芽、嫩叶上为害,在日均温度28.8℃时,卵期最短为5天,最长6天,平均5.24天。若虫期17天,脱皮4次;每雌产卵量212粒,产卵前期5～6天,产卵期8～14天,卵聚产或散产。其一生可交尾多次;完成一个世代约需30天,世代重迭,无明显越冬现象。虫口密度年消长与抽梢密切相关,春梢虫口密度达全年最高峰,与降雨量呈负相关,但不达显著。     

危害烟草的主要金龟甲生物学特性及综合防治

介绍了云南省烟草生产上常见的三种金龟甲：码绢金龟甲（Madadera sp．）、棕色金龟甲（Holotrichia fitanis Reitt）、铜绿丽金龟（Anomala corpulenta Motschulsky）的分部与危害及形态特征、发生特点及防治措施。     

肉桂枝枯病菌及其生物学特性研究

经致病性和形态鉴定,引致肉桂枝枯的病原菌,属于毛色二孢属的可可毛色二孢菌Lasiodiplodiatheobromae(Pat.)Griff.&Maubl。此菌的生长温度为12～39℃,以25～35℃比较适宜。分生孢子在水滴中的萌发率为90.82%,而在1%葡萄糖和蔗糖溶液中均为96%左右。菌丝体的致死温度52℃。分生孢子的致死温度53℃。病菌生长的酸碱度范围是pH2.5～11.7,以pH5.5最适宜。在连续光照的OMA培养基上,该菌产孢较快较多。     

西瓜枯萎病的研究进展

西瓜枯萎病是一种由土壤真菌引起的毁灭性病害,严重影响西瓜的生产。其病原菌镰刀菌可以在适合寄主生活的任何温湿度条件下生长,这给西瓜枯萎病研究带来了很大的困难。近年来,人们对西瓜枯萎病镰刀菌的生物学特性、致病机理和防治方法等方面进行深入的研究,本文对该病害的研究进展进行了总结。     

烟草赤星病菌的生物学特征

对烟草赤星病菌[Alternaria alternata(Fries)Keissler]的形态、生物学特性测定的结果表明:它的分生孢子呈链状串生,有分枝链,大小为11.3～51.3μm×5.6～16.3μm,平均25μm×9.3μm.病菌生长温度范围6～37℃,适宜温度为20～30℃,最适温度25℃;分生孢子的致死温度为49℃10min,或50℃5min,生长的酸碱度范围是pH3.03～12.49,最适pH为5.56。分生孢子在饱和相对湿度下萌发率仅46％,但在水滴中可达85％。在0.1％蔗糖液、0.1％葡萄糖液和5％烟叶汁中,孢子的萌发均良好,和在水滴中的比,无显著差异,其中以5％烟叶汁的萌发率较高(94.4％)。温度在20～30℃时均适宜孢子的萌发,但以25℃为最适宜。     

“加拿大一枝黄花”生物学特性观察及防除试验探讨

通过对“加拿大一枝黄花”野外和移植环境下生物学特性及其防除技术进行观察试验,掌握基本发生规律,初步探寻防治途径。     

土壤环境因素对致病性尖孢镰刀菌生长的影响

为了探索土壤环境因素对致病性尖孢镰刀菌(Fusarium oxysporum)存活和生长繁殖的影响,通过设定环境温度、土壤含水量和土壤p H等,研究了这些因素对尖孢镰刀菌西瓜专化型(FON)和黄瓜专化型(FOC)生长繁殖的影响。结果发现,致病性尖孢镰刀菌在21℃~30℃范围内能快速繁殖,而在45℃条件下则无法生长;土壤含水量为20%时该菌繁殖速度最快,而含水量为5%时则受到明显抑制;p H 4~5.5的偏酸性土壤适宜尖孢镰刀菌繁殖,而p H为中性或以上土壤均不利于该菌生长。结果表明,高温、干旱和碱性是减轻土壤中致病性尖孢镰刀菌繁殖的有利环境因素,通过创造相应环境条件,可以控制枯萎病的发生或蔓延。     

日本托特螨的生物学特性

日本托特螨（Tortonia sp.）是盗寄生性携播型螨类的一种。本研究通过室内人工饲养观察,对来源于日本的日本托特螨的形态特征进行了描述;并明确了此螨是营生于授粉昆虫——角额壁蜂（Osmia cornifrons（Radoszkowski））的巢筒育房中,属于盗寄生兼腐生性的螨类。在日本,此螨的年生活相有3相,以Ⅲ相中的幼螨、第1和第3若螨、成螨以及携播型第2若螨的虫态在壁蜂育房内过冬;成螨雌雄性比为1：1,无孤雌生殖,雌螨一生产卵量为（264.0±34.0）粒;各螨态在16～32℃温度条件下总发育历期为（52.1±5.5）～（14.7±2.0）d;此螨以寄主壁蜂贮存的食粮——花粉团和壁蜂的粪便为食料,26℃条件下取食这两种食料的发育历期虽有差异,但都能顺利生长发育并完成世代。本研究为日本托特螨的识别和防控提供了依据。     

西瓜枯萎病生防细菌的筛选

从６个土壤标本中分离得１５个细菌菌株,其中Ｂ１１、Ｂ１４、Ｂ１９、Ｂ２４等４个菌株为芽孢杆菌（Ｂａｃｉｌｌｕｓ ｓｐ．）,它们对西瓜枯萎病菌有较强的抑制作用。经室内和田间初步防治试验测定,它们对西瓜枯萎病有较好的防治效果。     

硝/铵营养对香蕉枯萎病尖孢镰刀菌生长的影响

通过室内平板培养,研究了不同硝/铵配比的氮源,以及不同的pH对香蕉枯萎病尖孢镰刀菌生长的影响。结果表明: 1）在所有不同硝/铵配比处理中,低pH（pH=4）均抑制尖孢镰刀菌的生长。在相同pH值条件下,100%铵态氮处理中尖孢镰刀菌的生长受到明显抑制,其菌落直径均小于4 cm; 2）在不同浓度铵处理后,尖孢镰刀菌的生长在铵态氮大于5 mmol/L时受到强烈的抑制; 3）通过模拟植物细胞壁被尖孢镰刀菌侵染并穿透的过程中发现,尖孢镰刀菌在100%铵态氮处理下不能穿透赛璐膜。本研究结果说明,铵态氮能够控制香蕉尖孢镰刀菌的生长,并抑制其侵染穿透寄主细胞壁。     

Succinic acid inhibited growth and pathogenicity of in vitro soil-borne fungus Fusarium oxysporum f. sp. niveum

Abstract

To clarify possible mechanisms of interaction of soil–plant–microbe for fusarium wilt of watermelon, succinic acid was added into the media to test its effect on in vitro Fusarium oxysporum f. sp. niveum in the ecological and biogeochemical cycling of soil–plant–microbe. Results showed that succinic acid decreased the growth and conidia germination of Fusarium oxysporum f. sp. niveum. The biomass and the conidia germinating rate were reduced by 10.1–59.8% and 14.4–21.4% respectively. Mycotoxin production and pathogenic enzyme activity by the fungus were suppressed at higher concentrations of succinic acid. Results suggested that succinic acid would not increase the risk of Fusarium oxysporum attacking plants, animals and humans due to its inhibition of fungus in the ecological and biogeochemical cycling of succinic acid in the interaction of soil–plant–microbe.     

拮抗菌强化的生物有机肥对西瓜枯萎病的防治作用

由西瓜专化型尖孢镰刀菌(Fusarium oxysporum f.sp.niveum)引起的西瓜枯萎病是导致西瓜生产毁灭性损失的土传病害,当前对该病尚无有效的防治措施.为了探索该病的生物防治效果,本研究从土壤中分离筛选西瓜枯萎病的拮抗菌,制成生物有机肥,通过温室盆栽试验检验防病效果,并对与拮抗相关的拮抗菌葡聚糖酶进行分子生物学检测.从不同土壤中分离纯化到对西瓜枯萎病菌有潜在拮抗作用的细菌172株,通过平板对峙法筛选出抑菌率在60％以上的拮抗细菌13株,从中挑选出2株抑菌率最高的菌株Cy5和CR38,分别用其与已腐熟的有机肥制成生物有机肥BIO5和BIO38.盆栽试验结果表明,BIO5在防病和促进西瓜生长方面表现优于BIO38.与对照相比,BIO5和BIO38对西瓜枯萎病的相对防治率分别为75％和25％.BIO5处理植株的株高、地上部鲜重、地上部干重分别比对照增加64.8％、63.0％和50％.施用生物有机肥还能显著改变根际土壤的微生物组成.BIO5处理根际土壤的细菌和枯草芽孢杆菌数量分别比对照增加48.5％和61.1％,真菌和尖孢镰刀菌的数量比对照分别下降52.1％和70.2％.分子生物学分析表明,菌株Cy5属于Paenibacillus jamilae菌株,并含有类似于P.polymyxa的β-1,3-1,4-葡聚糖酶.本研究结果说明,拮抗菌强化的生物有机肥对西瓜枯萎病有防治潜力.     

Effect of elevated atmospheric CO2 and temperature on disease severity of Fusarium oxysporum f.sp. lactucae on lettuce plants

Climate change effects on Fusarium oxysporum f.sp. lactucae (FOL) on lettuce plants grown under simulated climate change were studied. An artificial growing substrate was infested with FOL to reach a final concentration of 1 × 10⁴ CFU g⁻¹ of substrate. A non infested tank was used as control.Subsequently, 32 pots (2 l each) were prepared from the infested tank and other 32 pots were prepared from the non infested tank (control). Lettuce plants were then transplanted into the pots and grown in phytotrons under four simulated environmental conditions: (1) 800 ppm CO₂, 22–26 °C; (2) 800 ppm CO₂, 18–22 °C; (3) 400 ppm CO₂, 22–26 °C and (4) 400 ppm CO₂, 18–22 °C. Substrate samples were collected from each phytotron at 7, 14, 21 and 28 days after transplanting. Plate counts, enzymatic assays, and polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) analyses were performed to evaluate the effect of climate change on the microbial population. The abundance of Fusarium spp. and the severity of Fusarium wilt of lettuce varied significantly as a consequence of increased temperature (22–26 °C). Increased CO₂ levels showed no effect on the severity of Fusarium wilt of lettuce and on the abundance of Fusarium spp. On the other hand, the total bacterial abundance was reduced at elevated CO₂ concentration (800 ppm). PCR-DGGE fingerprints of the ascomycete community obtained from DNA directly extracted from infested substrate samples did not change as a consequence of elevated temperature and CO₂.Enzymatic activities were not affected by the elevated CO₂ level. Our study indicates that the CO₂ concentration used in our experiment had no detectable impact on Fusarium wilt of lettuce. Only temperature influenced all observed parameters, but did not affect the fungal species diversity. Other factors, such as nutrient limitation and the effect of plant species needs further study.     

根际施用微生物有机肥防治连作西瓜枯萎病研究

为了探讨西瓜专用微生物有机肥料(BOF)对西瓜植株枯萎病的防治效果,采用盆栽试验研究了西瓜专用BOF对连作土壤上西瓜植株生长和枯萎病的防治效果以及西瓜枯萎病致病菌的数量分布的影响。结果表明:1）营养钵育苗和移栽土壤中都施用BOF的处理,未发现西瓜枯萎病植株,而对照植株则完全发病;2）施用BOF处理的致病菌（尖孢镰刀菌西瓜专化型）数量在根际土壤中为0.7×103 cfu/g,在土体土壤中为2.7×103 cfu/g,都控制在104 cfu/g数量级以下,而对照处理的数量分别达到了1.17×105 cfu/g和1.1×105 cfu/g;3）与对照比较,营养钵育苗时施用1%的BOF,西瓜苗期（播种后17 d）生物量都显著增加,根系生物量比地上部生物量提高了16.7个百分点（以鲜重计）和24.8个百分点(以干重计);营养钵育苗和移栽土壤中均施用BOF的处理,西瓜植株（生长67 d）生物量（干重）是对照的1.83倍;在营养钵育苗或移栽时施用BOF的处理,西瓜植株干重两者差异不大,分别是对照的1.28倍和1.27倍。采用营养钵育苗和移栽时都施用BOF的方法种植西瓜,能有效地促进西瓜植株生长,防止西瓜枯萎病发生,克服西瓜连作障碍。     

Cinnamic acid inhibits growth but stimulates production of pathogenesis factors by in vitro cultures of Fusarium oxysporum f.sp. niveum

Long-term monoculture of watermelon leads to frequent occurrence of watermelon fusarium wilt caused by Fusarium oxysporum f.sp. niveum (FON). Some allelochemicals contained in watermelon root exudates and decaying residues are possibly responsible for promoting the wilt disease. The purpose of this study was to evaluate the allelopathic effect of artificially applied cinnamic acid on FON. Results demonstrated that hyphal growth of FON was strongly inhibited by cinnamic acid. At the highest concentration of cinnamic acid, the biomass in liquid culture was decreased by 63.3%, while colony diameter, conidial germination on plates, and conidial production in liquid culture were completely inhibited. However, mycotoxin production and activity of phytopathogenic enzymes were greatly stimulated. Mycotoxin yield, pectinase activity, proteinase activity, cellulase activity, and amylase activity were increased by 490, 590, 760, 2006, and 27.0%, respectively. It was concluded that cinnamic acid dramatically stimulated mycotoxin production and activities of hydrolytic enzymes by FON but inhibited growth and germination of FON. The findings presented here indicate that cinnamic acid is involved in promoting watermelon fusarium wilt.