蜡蚧轮枝菌VL17菌株代谢产物对桃蚜若蚜的室内毒力

蜡蚧轮枝菌(Verticillium lecanii)VL17菌株液体发酵滤液,经乙酸乙酯萃取并旋转蒸发后,获得粗毒素。采用浸渍法测定粗毒素对桃蚜(Myzus persicae)的毒力。结果表明:0.375mg/mL粗毒素对桃蚜若蚜的LT50为8.3821d,随浓度增加其杀虫速度加快;处理试虫第3天,粗毒素对桃蚜若蚜的LC50为3.9661mg/mL,随处理时间延长其毒力增强。     

蜡蚧轮枝菌对害虫致病性的初步研究

通过对蜡蚧轮枝菌V-816菌株致病性的研究 ,结果表明 ,该菌对菜青虫、小菜蛾、甘蓝蚜、棉红蜘蛛有较强的致病力。随浓度增加 ,杀虫效果明显提高 ,对幼龄幼虫致病力比老龄幼虫强。温度对该菌的致病力有明显的影响 ,其适温为25～30℃。试验表明该菌不侵染七星瓢虫的幼虫     

蜡蚧轮枝菌对月季长管蚜的毒力测定

研究结果表明蜡蚧轮枝菌对月季长管蚜有较强的致病性,孢子浓度2.0×105个/mL时可造成大量月季长管蚜感染死亡,其LT50=（6.62±0.14）d; 而高浓度2.0×108个/mL对月季长管蚜感染致死的LT50=（4.69±0.16）d,第8天的死亡率达93.6%,致死中时随浓度增加而缩短。第5天的致死中浓度为（1.72±0.18）×107个/mL,第8天为（1.53±0.15）×104个/mL,致死中浓度随时间增加而减小。     

紫外线对蜡蚧轮枝菌原生质体的诱变效果

本研究利用紫外线对蜡蚧轮枝菌原生质体及分生孢子的诱变,获得了3个产孢量比对照提高10倍以上的菌株,其对桃蚜及绣线菊蚜的致死率比对照菌株提高30～50％。连续三代培养、保藏半年的突变菌株,其产孢量及对蚜虫的致死率均保持稳定。     

营养和农药对蜡蚧轮枝菌生长发育的影响

在25℃条件下,测定了4种培养基和8种农药对蜡蚧轮枝菌生长发育的影响。结果表明,马铃薯葡萄糖和查氏培养基最适于菌丝生长和产生分生孢子。所有供试农药对蜡蚧轮枝菌菌丝生长均有显著的抑制作用,其中代森锰锌的抑菌率高达100%,其次为代森锌、百菌清及敌敌畏,再次为氯氰菊酯和阿维柴油,链霉素和氟虫腈的抑菌率最低。     

蜡蚧轮枝菌毒素防治温室白粉虱初步研究

从俄罗斯全俄植保所引入的蜡蚧轮枝菌Tri-BA81 ,经发酵培养 ,萃取得到代谢产物粗毒素 ,并将粗毒素用于防治温室白粉虱的研究。结果表明 :该提取物具有很高的杀虫活性。 2%和4%粗毒素液对温室内白粉虱成虫平均死亡率分别为96.46%和100% ,1%和2%粗毒素液对保护地成虫的平均防治效果为81.75%和84.17%。对若虫的防治效果也能达到50%以上     

蜡蚧轮枝菌防治植物病虫害研究进展

蜡蚧轮枝菌在蔬菜病虫害防治中有很大开发潜力。就蜡蚧轮枝菌的致病性、环境条件对其生长的影响、储藏期存活率及在生产中应用的概况的研究进展进行了综述。研究进展表明,该种真菌既可以防治粉虱、蚜虫、蓟马等蔬菜害虫,又可以防治蔬菜的白粉病、锈病等。     

蜡蚧轮枝菌致病性初步研究

通过对蜡蚧轮枝菌V-816菌株致病性的研究,结果表明,该菌对菜青虫、小菜蛾、甘蓝蚜、棉叶螨有较强的致病力。随浓度增加,杀虫效果明显提高,且对幼龄幼虫的致病力较对老龄幼虫的强。温度对该菌的致病力有明显的影响,其致病适温为25～30℃。同时试验表明该菌不侵染七星瓢虫的幼虫。     

Toxicity and feeding deterrence of crude toxin extracts of Lecanicillium (Verticillium) lecanii (Hyphomycetes) against sweet potato whitefly, Bemisia tabaci (Homoptera: Aleyrodidae)

Crude toxins [toxin(V3450) and toxin(Vp28,) extracted from Lecanicillium (Verticillium) lecanii (Zimmermann) Gams & Zare strain V3450 and Vp28 respectively] were tested for contact toxicity, feeding deterrence and repellent activity against the sweet potato whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). Both toxins showed ovicidal activity to eggs, with LC(50) values of 447 and 629 mg L(-1) respectively. Nymphs of B. tabaci were the most susceptible stages (LC(50) values were calculated at 111 mg L(-1) for toxin(V3450) and 216 mg L(-1) for toxin(Vp28)), and adults were the second most susceptible stages (48 h LC(50) values were calculated at 178 mg L(-1) for toxin(V3450) and 438 mg L(-1) for toxin(Vp28)). Applied to seedlings at a concentration of 400 mg L(-1), the toxins significantly (P < 0.001) reduced the hatching of whitefly eggs and the subsequent survival rate of the nymphs, and the emergence and fecundity of the progeny adults. Both toxins exhibited repellent activity at low concentration (100 mg L(-1)), with repellency index (RI) values of 0.645 for toxin(V3450) and 0.642 for toxin(Vp28), and antifeedant activity at high concentration (1000 mg L(-1)) to adults, with antifeedant index (AFI) values of 0.713 for toxin(V3450) and 0.749 for toxin(Vp28). The results of the present study demonstrate the toxicity, repellence and antifeedant properties of the fungi metabolite toxins on B. tabaci, which might develop as environmentally friendly plant protectant(s).     

蜡蚧轮枝菌的新株系(Lecanicillium lecanii-01Et)对介壳虫的毒力测定

对从未喷药的中国农业大学校园露地栽培的辣根上采集的介壳虫制作成永久玻片后进行鉴定,初步判断为梨绒蚧(Eriococcus tokaedae Kuwana)。将蜡蚧轮枝菌(Lecanicillium lecanii)Bj085-1菌株分生孢子配成(1.4×104)～(1.4×108)孢子/mL的5个处理浓度,对梨绒蚧若虫进行第1次毒力测定。结果显示,各个处理浓度之间的平均累计死亡率大致随着孢子浓度的增加而增加,其中以(1.4×108)孢子/mL浓度处理的最高,但只有45.7%。其后将第1次毒力测定试验中死亡虫体经保湿后出现的菌丝体进行分离纯化,获得了新株系(Lecanicillium lecanii-01Et)进行第2次毒力测定(方法同第1次)。结果表明,不同浓度的L.lecanii-01Et分生孢子对梨绒蚧若虫的杀虫速度随浓度的增加而明显加快,浓度增至(1.4×108)孢子/mL时,杀虫速度最快,LT50仅为3.95 d,平均累计校正死亡率达84.1%。说明分离纯化后的蜡蚧轮枝菌新株系(L.lecanii-01Et)分生孢子对梨绒蚧若虫有较好的防治作用。     

虫生蜡蚧轮枝菌的生产菌株筛选与生物学特性

通过菌株分生孢子萌发、菌落生长、液体和固体产孢等试验,综合评价了8个高毒力蜡蚧轮枝菌菌株用于工业发酵生产的可能性.结果表明,一株来自中国福建北部山区果园,主要寄生粉虱的菌株CA-0319,萌发特性较好,12h萌发率达90.1%;菌落生长速率为0.385cm/d;液体摇瓶培养72h产孢1.091×109个/ml;固体培养7d产孢5.525×108个/皿.另一来自北京,主要寄生蓟马菌株LB-035,12h萌发率达到94.5%,菌落生长速率为0.356cm/d;液体摇瓶培养72h产孢1.210×109个/ml;固体培养7d产孢达3.806×108个/皿.     

蜡蚧菌和3种低浓度杀虫剂混用对大豆蚜的影响

为研究蜡蚧菌与新型生物农药混用在生物防治中的应用,本文采用PDA培养基培养蜡蚧菌BNCC336750分生孢子。采用浸渍法对大豆蚜进行毒力测定,选取最佳防治效果的10⁸孢子/mL的孢子悬浮液浓度与亚致死浓度的化学农药35%吡虫啉悬浮剂和生物农药0.3%印楝素乳油、0.5%苦参碱水乳剂进行混配。结果表明,大豆蚜的累计校正死亡率随菌株孢子悬浮液浓度的增大而增大,当浓度为10⁸孢子/mL时对大豆蚜毒力最高。菌药混用对大豆蚜的防治效果比单用蜡蚧菌BNCC336750孢子悬浮液或亚致死浓度生物农药的防治效果都要好。其中菌株BNCC336750孢子悬浮液与印楝素混用效果最好,处理7 d后大豆蚜累计死亡率达到94.16%。与苦参碱和吡虫啉混用7 d后大豆蚜累计死亡率分别为86.13%和80.29%。田间试验表明,印楝素混配菌株BNCC336750孢子悬浮液效果最好,7 d后防治效果达到89.47%。     

一株高毒力刀孢蜡蚧菌最适培养条件的优化及其对桃蚜的毒力测定

刀孢蜡蚧菌Lecanicillium psalliotae是一种重要的昆虫病原真菌,在害虫生物防治中应用广泛.为明确刀孢蜡蚧菌生长和产孢的最适培养条件,本文对一株刀孢蜡蚧菌HFLP006菌株的培养条件进行优化,比较了不同培养基种类、初始接菌量、培养温度、供试碳源和氮源对该菌株产孢量的影响.结果 表明,在SDAY液体培养...     

4株拮抗细菌对棉花黄萎病的防治效果及机制

棉花黄萎病严重制约新疆棉花持续高产和稳产,拮抗细菌在棉花黄萎病生物防治中潜力巨大。本研究旨在明确4株拮抗细菌对棉花黄萎病的防治效果及其机制,为棉花黄萎病的生物防治提供理论依据。本文采用共培养法,研究4株拮抗细菌对黄萎病菌分生孢子浓度、菌丝和孢子形态、膜透性和产毒素能力的影响,采用滤液接种法进行盆栽试验验证其对棉花黄萎病的防治效果,采用愈创木酚法和氮蓝四唑光化还原法测定棉株体内防御酶系的活性。结果表明,4株拮抗细菌能够减少黄萎病菌分生孢子浓度,破坏其细胞形态,导致其细胞膜破裂,降低其毒蛋白浓度。接种4株拮抗细菌,能够诱导棉株体内POD酶和SOD酶等防御酶系的积累,提高了棉花的抗病能力,由菌株SHZ-24、SHT-15、SMT-24和BHZ-29处理的棉花,其对棉花黄萎病的最高防治效果分别为73.82%、80.48%、84.91%和84.18%。4株拮抗细菌通过抑制黄萎病菌的生长和诱导植物产生防御反应来提高对棉花黄萎病的抗性,其对棉花黄萎病具有良好的防治效果。     

弱毒黄萎病菌的筛选及诱导向日葵交互保护作用的条件优化

向日葵黄萎病是一种难以防治的土传病害。本研究通过毒力和致病力双重评价标准筛选得到一株弱毒黄萎病菌菌株Vn-1,采用诱导接种和挑战接种方法,明确了弱毒菌株Vn-1可以诱导向日葵产生对黄萎病菌的交互保护作用。本试验进一步对菌株Vn-1诱导间隔期和诱导浓度进行了条件优化,并在最优条件下探究其交互保护作用的持效性以及对向日葵植株生长情况的影响。结果表明,菌株Vn-1诱导向日葵交互保护的最佳诱导间隔为5 d,最佳诱导浓度为1×10⁶孢子/mL;在最佳诱导条件下,防效最大可达72.27%,且在挑战接种44 d后维持防效在30%以上;对比直接接种强毒菌株处理,最佳诱导条件下,向日葵株高和根长显著提高,表明菌株Vn-1诱导能够减小强毒菌株对向日葵植株生长的抑制作用。     

Comparison of three biological control agents against cucumber powdery mildew (Sphaerotheca fuliginea) in semi-commercial-scale glasshouse trials

The effect of three reported biological control agents, Ampelomyces quisqualis, Verticillium lecanii and Sporothrix flocculosa, was tested against cucumber powdery mildew (Sphaerotheca fuliginea). Two glasshouse experiments, one in the summer and one in winter/spring were conducted on a semi-commercial scale. In both experiments, a susceptible and a partially resistant cultivar were used. In the second experiment, the additional effect of integration of biological control and silicon amendments to the nutrient solution was also assessed. In both experiments, A. quisqualis did not control the disease. V. lecanii had a small effect on powdery mildew in the first experiment but not in the second. S. flocculosa gave the best control of powdery mildew in both experiments. In the first experiment, weekly application of S. flocculosa reduced disease in the partially resistant cultivar to the same level as a treatment in which the fungicides bupirimate and imazalil were each applied once. Addition of silicon in the nutrient solution in a concentration of 0.75 mM reduced disease by 10–16%, averaged over all treatments. There was no interaction between silicon and the biocontrol agents. Yield was recorded in the second experiment and was significantly increased by the fungicide treatment compared to the control in the partially resistant cultivar. Yield in the treatment with S. flocculosa was not significantly different from the fungicide treatment in this cultivar. Silicon had no effect on yield in either cultivar.     

CTV强弱毒株促进褐色橘蚜的取食

正由柑橘衰退病病毒(Citrus tristeza virus,CTV)引起的柑橘衰退病,对全世界柑橘产业造成了严重威胁。褐色橘蚜Toxoptera citricida(Kirkaldy)属半翅目蚜科,以非循回型半持久方式传播CTV,是CTV的最有效传播媒介~([1])。我国广泛分布着CTV的各种株系和传媒褐色橘蚜,对我     

Evidence for hyperparasitism of coffee rust (Hemileia vastatrix) by the entomogenous fungus, Lecanicillium lecanii, through a complex ecological web

The entomogenous fungus, Lecanicillium lecanii is hyperparasitic on Hemileia vastatrix , the cause of coffee leaf rust in the laboratory, and has frequently been observed attacking it in the field. The existence of a complex ecological web involving the spatially clustered mutualism of an ant ( Azteca instabilis ) with a scale insect ( Coccus viridis ), where the scale insect was infected by L. lecanii , prompted a search for a spatial correlation between the attack of L. lecanii on the scale insect and the incidence of rust in a commercial coffee crop. A weak but statistically significant effect of hyperparasitic control of coffee rust was observed on two distinct scales: in a 45-ha plot and on a scale of approximately 10 m. It was concluded that this effect was linked to an indirect effect of the ant–coccid mutualism, where L. lecanii was a parasite of the coccid.