Tissue distribution of cadmium and its effect on reproduction in Spodoptera exigua

Vegetable fields are often contaminated by heavy metals,and Spodoptera exigua is a major vegetable pest which is stressed by heavy metals mainly by feeding.In this study,cadmium accumulation in the tissues of S.exigua exposed to cadmium and its effects on the growth and development of the parents and the offspring were investigated.Under the stress of different concentrations of cadmium(0.2,3.2,and 51.2 mg kg^(-1)),the cadmium content in each tissue of S.exigua increased in a dose-dependent manner.At the larval stage,the highest cadmium accumulation was found in midgut in all three cadmium treatments,but at the adult stage,the highest cadmium content was found in fat body.In addition,the cadmium content in ovaries was much higher than in testes.When F1S.exigua was stressed by cadmium and the F_(2)generation was not fed a cadmium-containing diet,the larval survival,pupation rate,emergence rate and fecundity of the F_(2)generation were significantly reduced in the 51.2 mg kg^(-1)treatment compared to the corresponding F1generation.Even in the F_(2)generation of the 3.2 mg kg^(-1)treatment,the fecundity was significantly lower than in the parental generation.The fecundity of the only-female stressed treatment was significantly lower than that of the only-male stressed treatment at the 3.2 and 51.2 mg kg^(-1)cadmium exposure levels.When only mothers were stressed at the larval stage,the fecundity of the F_(2)generation was significantly lower than that of the F1generation in the 51.2 mg kg^(-1)treatment,and it was also significantly lower than in the 3.2 and 0.2 mg kg^(-1)treatments.The results of our study can provide useful information for forecasting the population increase trends under different heavy metal stress conditions and for the reliable environmental risk assessment of heavy metal pollution.

Induced CTL-S15 gene expression by Bacillus thuringiensis declines susceptibility in Spodoptera exigua

It has been reported that C-type lectins(CTLs),which are pattern recognition receptors of the insect innate immunity response,may compete with Cry toxin for the receptor alkaline phosphatase to decrease its toxicity in insects.However,to date,which CTLs affect larval susceptibility to Bt in Spodoptera exigua is not clear.In this study,33 CTL genes were identified from S.exigua.Based on the number of carbohydrate-recognition domains(CRDs)and the domain architectures,they were classified into three groups:(1)nineteen CTL-S(single-CRD),(2)eight immulectin(dual-CRD)and(3)six CTL-X(CRD with other domains).RT-qPCR analysis revealed that expression levels of SeCTL-S15,IML-4 and CTL-X6 were upregulated after challenge with Bt and Cry1Ab.Tissue and developmental stage expression analysis showed that only SeCTL-S15 was mainly expressed in the midgut and larva,respectively.Knockdown of SeCTL-S15 significantly increased Bt susceptibility,as indicated by reduced survival and larval weight.These results suggest that CTL-S15 might play a vital role in the low susceptibility of larvae to Bt in S.exigua.Our results provide new insights into CTL function in insects.

Impact of Variegated Temperature, CO<SUB>2</SUB>and Relative Humidity on Survival and Development of Beet Armyworm <i>Spodoptera exigua</i>(Hubner) under Controlled Growth Chamber

Climate change will have a noteworthy bearing on survival, development, and population dynamics of insect pests. Therefore, we contemplated the survival and development of beet army worm, Spodoptera exigua under different temperatures, (15°C, 25°C, 35°C, and 45°C), CO2 (350, 550, 750 ppm) and relative humidity (55%, 65%, 75% and 85%) regimes. Maximum larval and pupal weights were recorded in insects reared at 25°C. The growth of S. exigua was faster at 35°C (larval period 7.4 days and pupal period 4.5 days) than at lower temperatures. At 15°C, the larval period was extended for 61.4 days and there was no adult emergence from the pupae till 90 days. The S. exigua hatchling was absent at 45°C. The larval survival ranged from 31.6% - 57.2%, maximum survival was recorded at 25°C, and minimum at 45°C. The maximum (84.27%) and minimum adult emergence were recorded in insects reared at 25°C and 35°C respectively. Maximum fecundity (384.3 eggs/female) and egg viability (51.97%) were recorded in insects reared at 25°C. Larval and pupal periods increased with an increase in CO2 concentration. The highest pupal weights (128.6 mg/larva) were recorded at 550 ppm. The highest larval survival (73.50%) was recorded at 550 ppm and minimum (37.00%) at 750 ppm CO2. Fecundity was the highest in insects reared at 550 ppm CO2 (657.4 eggs/female), and the lowest at 750 ppm. Maximum larval and pupal weights were recorded in insects reared at 75% relative humidity (RH). The growth rate of S. exigua was faster at 85% RH than at lower RH. The larval survival ranged between 40.0% - 58.5%. Maximum adult emergence (88.91%) was recorded in insects reared at 75% RH and minimum at 85% RH. Maximum fecundity (447.6 eggs/female) and the highest egg viability (72.95%) were recorded in insects reared at 75% and 65% RH respectively. Elevated temperatures and relative moistness will diminish the life cycle, while hoisted CO2 will drag the life expectancy. Therefore, there is a need for thorough assessment of the impact of climatic factors on the population dynamics of insect pests, crop losses, and sustainability of crop production.

Insect Resistance of Different Tissues of Transgenic Cotton to Spodoptera exigua(Hbner)

[Objective] The aim was to learn the resistance of different tissues and organs of transgenic cotton to Spodoptera exigua （Hbner）. [Method] Flowers,the 1st,the 3rd,the 6th and the 14th leaves from the top of 33B,GK12 and SGK321 were used to feed S. exigua neonates respectively. Survival larvae and dead ones were counted on the 3rd,the 7th,the 10th,the 16th and the 19th day; meanwhile,the pupae amount was recorded,and the pupae weight was measured at the 24th h after pupation. [Result] The survival curves,pupation rates and pupae weights of S. exigua feeding on different tissues of transgenic cotton were not significantly different from those of S. exigua feeding on the corresponding tissues of conventional cotton; pupation rate of S. exigua feeding on different leaves of the same cotton variety were not significantly different from each other,but all higher than that of S. exigua feeding on the flowers of that cotton; and there were no differences among pupation weights of S. exigua feeding on different leaves or flowers of the same cotton variety. [Conclusion] Transgenic cotton showed weak resistance to S. exigua. Hence,in the transgenic cotton fields,more attention should be paid to occurrence trend of S. exigua and its control.

交配和温度对甜菜夜蛾(Spodoptera exigua)雌蛾性信息素产生的影响

研究表明 ,交配对甜菜夜蛾雌蛾性信息素各组分的滴度、比例及其在个体间的变异均无显著的影响 ,因此交配不影响雌蛾在下一暗期的再次求偶和交配 .环境温度对甜菜夜蛾性信息素的产生则有显著的影响 .15～ 2 5℃最有利于甜菜夜蛾性信息素的产生 ,而 10℃低温和 35℃高温则使性信息素产生受到明显影响 ,其中以 10℃低温的影响更甚 .10℃低温处理不仅使各组分的滴度产生显著改变 ,而且使二元性信息素组分的比例受到显著影响 ,并使二元组分通讯信道的个体间变异明显增大 (CV >10 % ) .这些改变必将扰乱甜菜夜蛾雌雄间的正常交配 .

甜菜夜蛾(Spodoptera exigua)自然种群与抗拟除虫菊酯有关的L1014F突变的发现

应用PCR扩增技术 ,克隆了甜菜夜蛾 (Spodopteraexigua)自然种群的部分钠离子通道基因片段 ,并对其进行了测序 .后将推断的氨基酸序列与其它敏感昆虫的相应序列进行了比较 ,发现在钠离子通道ⅡS6的 10 14同源位点上存在Leu(CTT)→Phe(TTT)点突变 ,表明该种群的抗药性可能与击倒抗性 (kdr)

Field Trials of 20% Tebufenozide SC against Spodoptera exigua Hbner

[Objective] The study was aimed to determine and evaluate control effect and security of 20% tebufenozide SC against Spodoptera exigua HObner, which would provide technical support for its promotion and utilization. [ Method] By using foliar spray method, control effects of different concentration of 20% tebufenozide SC and 25 g/L deltamethrin EC against S. exigua were determined. [ Result] 20% tebufenozide SC had better control effects on S. exigua. After spraying for 3 and 7 d, control effects of 20% tebufenozide SC in each treatment could reach 81% and 84%, which was higher than 25 g/L deltamethdn EC treatment. [ Conclusion] 20% tebufenozide SC for controlling S. exigua had good effect, which had permanent effectiveness for over 7 d. It also caused less environmental pollution, and was safe to cabbage, being the ideal pesticide for controlling S. exigua in vegetables.

A Fragment of Cadherin-Like Protein Enhances Bacillus thuringiensis Cry1B and Cry1C Toxicity to Spodoptera exigua(Lepidoptera:Noctuidae)

Cry toxins produced by Bacillus thuringiensis（Bt） are effective biological insecticides against certain insect species.In this study,bioassay results indicated that Cry1B and Cry1C were toxic to Spodoptera exigua.We also identified a cadherin-like gene in S.exigua that could enhance the toxicity of Cry1B and Cry1C.The cadherin-like gene identified from the larvae midgut tissue was cloned by reverse transcription polymerase chain reaction（RT-PCR） and rapid amplification of cDNA ends（RACE）.The full-length cDNA of the gene consisted of 5 220 bp encoding 1 740 amino acid with a predicted molecular mass of 196 kD.BLAST search analysis showed that the predicted amino acid sequence had a high sequence identity to the published sequences of cadherin-like proteins from other Lepidoptera insects.Spatial expression of the cadherin-like gene detected by qRT-PCR analysis revealed that the cadherin-like gene was mainly present in the gut of 4th instar larvae and during different life stages.The results suggested that the commercial development of this synergist has the potential to enhance Cry1B and Cry1C toxicity against Lepidoptera insects.

Effect of Host Plants on Development,Fecundity and Enzyme Activity of Spodoptera exigua (Hübner)(Lepidoptera:Noctuidae)

The beet armyworm,Spodoptera exigua （Lepidoptera：Noctuidae）,is an economically important pest of crops worldwide,attacking plants from over 20 families including trans-continental agricultural cotton,corn and citrus crops.In this study,performance and subsequent enzyme activity of beet armyworm reared on host plants from five families were investigated.Significant differences were found in development,fecundity and enzyme activity on different host plants.Survival rate was the highest （42.8%） on asparagus lettuce （Lactuca sativar var.asparagina） and the lowest （17.0%） on sweet pepper （Capsicum annuum）.Larval duration was the shortest on asparagus lettuce （12.0 d）,and was 43.4% longer on sweet peppers （21.2 d）.The activity of acetylcholine esterase （AChE） and carboxylesterase （CarE） in 3rd instar larvae,and soluble carbohydrate and crude protein contents in different host plants were determined.AChE activity was the highest in the larvae feeding on Chinese cabbage （Brassica rapa）,but declined by nearly 60% on maize （Zea mays） seedlings.The ratio of soluble carbohydrate content to crude protein content in host plants was found to have a positive effect on oviposition and a negative correlation with larval duration and life time （from larval to adult stages） of the insect.

Joint Toxicity of Beauveria bassiana and Two Insect Growth Regulators on Beet Armyworm,Spodoptera exigua(Hübner)

Joint toxicity of Beauveria bassiana and two insect growth regulators, methoxyfenozide and hexaflumuron, on beet annywonn larvae, Spodoptera exigua （ Htthner）, were investigated. An obvious synergism effect of the two insect growth regulators with B. beauveria was observed. When the insect growth regulators at LC50 concentrations （25 × 10^-6 g/L for methoxyfenozide and 1 000 × 10^ -6 g/L for hexaflumuren） were mixed with B. bassiana at the volume ratio of 4： 1, the mixtures achieved the best efficacy. The co-toxicity co-efficient （CTC） of methexyfenozide and B. bass/ana was 285, and that of hexaflumuron and B. bass/ana was 208. Scanning electron microscope observation of the longitudinal section of S. exigua revealed obviously different patterns of integument in different treatment groups.

Cloning and Sequencing of a Gene Encoding GOBP2 in the Antenna of Spodoptera exigua

A pair of degenerate primers was designed, based on the comparison of five insects' GOBP2 gene sequences reported previously. A specific band (about 400bp in length) was amplified from cDNA of Spodoptera exigua antenna and another specific band (about 2kb in length) was amplified from genomic DNA. The two segments were cloned into T-easy vector, respectively. Results of sequencing and structural analysis showed that the full-length of GOBP2Sexi ORF is 426bp, 141 amino acid residues were encoded. The predicted MW and pI are 16.07ku and 5.09 .respectively. There are six conservative Cys locus in the sequence, which is the typical characteristic of OBPs. GOBP2Sexi gene was inserted by two introns between amino acid residue 22 and 23 and between 82 and 83. The length of two introns is 160bp and 1403bp. Results of Northern blot showed that GOBP2 gene expressed specifically in the antenna of Spodoptera exigua, and the expression level is nearly equal in the antenna of male and female moths. The sequence was deposited in GenBank/EMBL and the accession number is AJ294809.

两种昆虫生长调节剂类杀虫剂对甜菜夜蛾幼虫储存蛋白含量的影响

通过阴离子交换、凝胶过滤等方法对甜菜夜蛾5龄幼虫储存蛋白进行纯化,采用SDS-PAGE、ELISA等方法测定甜菜夜蛾储存蛋白动态变化,研究两种昆虫生长调节剂类杀虫剂甲氧虫酰肼和氟啶脲在亚致死剂量下对储存蛋白含量的影响。结果表明:甜菜夜蛾幼虫储存蛋白亚基分子量为85.1 ku。在5龄幼虫血淋巴中储存蛋白质量浓度随日龄逐渐增加,于5龄第3天达到最大值30.76 mg∕mL。低剂量的甲氧虫酰肼能够提高幼虫血淋巴中储存蛋白的浓度,处理48 h和72 h后,LC10处理组的储存蛋白质量浓度分别为19.27 mg∕mL和45.21 mg∕mL,显著高于对照组。高剂量的甲氧虫酰肼对甜菜夜蛾储存蛋白存在着明显的抑制作用,LC40处理组在72 h后,血淋巴中储存蛋白浓度仅为对照组的48.47%。氟啶脲LC10、LC40两个处理组的储存蛋白浓度在各个处理时间均低于对照组,特别是在处理48 h和72 h后,血淋巴中储存蛋白浓度显著降低,且氟啶脲浓度越高,影响越显著,LC40处理组在72 h后,血淋巴中储存蛋白浓度仅为对照组的26.77%。研究结果可为进一步揭示两种杀虫剂对甜菜夜蛾幼虫的毒力作用提供理论依据。

草地贪夜蛾与甜菜夜蛾种内和种间的竞争行为

草地贪夜蛾Spodoptera frugiperda(Smith)和甜菜夜蛾Spodoptera exigua(Hübner)是我国重要的农作物害虫,存在很多共同的寄主植物。为明确草地贪夜蛾和甜菜夜蛾的竞争关系,本文在食物充足和食物缺乏条件下,研究了草地贪夜蛾和甜菜夜蛾种内和种间竞争行为;研究了不同初始种群密度草地贪夜蛾和甜菜夜蛾初孵幼虫在相同生态位的种群竞争行为。结果表明:无食物条件下,扭动行为是草地贪夜蛾种内竞争最主要的行为表现,其中3龄与5龄幼虫组合扭动行为出现次数最多,为8.57±0.49次/30 min。与无食物处理相比,有食物处理下草地贪夜蛾攻防行为次数较少。种间竞争中,在无食物条件下二者攻击行为主要表现为头部接触,防御主要表现为扭动行为,其中草地贪夜蛾4龄幼虫与甜菜夜蛾5龄幼虫竞争时头部接触和扭动行为最频繁,分别出现5.03±2.43次/30 min和18.47±5.92次/30 min。此外,同一龄期的草地贪夜蛾和甜菜夜蛾种间竞争中,草地贪夜蛾存活率更高;不同龄期两者竞争时,龄期相对较高的幼虫存活率更高,且有食物时两者存活率均高于无食物处理。种群竞争的室内模拟研究中,草地贪夜蛾和甜菜夜蛾种群的存活率随共存时间的增加逐渐降低。重复测量方差分析表明,5头草地贪夜蛾幼虫与40头甜菜夜蛾幼虫接入玉米苗后,共存时间没有显著影响草地贪夜蛾幼虫的存活率,但甜菜夜蛾幼虫的存活率受共存时间影响显著;其他组合中共存时间均显著影响草地贪夜蛾与甜菜夜蛾幼虫的存活率,其中,40头草地贪夜蛾幼虫与40头甜菜夜蛾幼虫接入玉米苗后,两者存活率均存在显著差异,草地贪夜蛾的存活率显著高于甜菜夜蛾,草地贪夜蛾种群可能取代甜菜夜蛾种群。研究结果可为明确草地贪夜蛾和甜菜夜蛾的种群演替规律及制定科学的防治措施提供参考。

异色瓢虫对甜菜夜蛾和草地贪夜蛾的捕食潜能

为明确异色瓢虫Harmonia axyridis对甜菜夜蛾Spodoptera exigua和草地贪夜蛾Spodoptera frugiperda的捕食潜能,本文在室内条件下研究了异色瓢虫对上述2种鳞翅目害虫2龄幼虫的捕食功能反应和搜寻效应;在网室条件下测定了异色瓢虫对2种害虫低龄幼虫的防控效果。室内研究结果表明,异色瓢虫雌雄成虫对这2种害虫2龄幼虫的捕食功能反应均属于HollingⅡ型圆盘方程,其中雌成虫对甜菜夜蛾和草地贪夜蛾2龄幼虫的瞬时攻击率(a)分别为1.120和0.987,控害效能(a/T_(h))分别为134.514头和154.408头,日最大捕食量(1/T_(h))分别为120.124头和156.437头;雄成虫对甜菜夜蛾和草地贪夜蛾2龄幼虫的瞬时攻击率(a)分别为1.071和0.830,控害效能(a/T_(h))分别为116.262头和124.568头,日最大捕食量(1/T_(h))分别为108.540头和150.039头。网室试验结果表明,2∶300、4∶300和8∶300的益害比下异色瓢虫均能有效控制甜菜夜蛾和草地贪夜蛾低龄幼虫的数量,释放后8 d防效分别在65%、80%和95%以上。综上所述,异色瓢虫具备对甜菜夜蛾和草地贪夜蛾低龄幼虫有效控害的潜力,试验结果可为利用异色瓢虫防控甜菜夜蛾和草地贪夜蛾提供理论依据。

甜菜夜蛾SeABCB3基因的克隆、表达及与Bt Cry1Ab35的结合特性分析

为了深入解析Cry1Ab蛋白对主要农业害虫甜菜夜蛾的作用机制,本研究开展了甜菜夜蛾ABC转运蛋白(ATP-binding cassette transporter)与Bt Cry1Ab35蛋白的结合特性研究。首先,本研究克隆获得了甜菜夜蛾ABC转运蛋白Se ABCB3全长基因序列(GenBank登录号为OP948097),开放阅读框为3915bp,编码1304个氨基酸,预测蛋白分子量为142.66kDa。进一步克隆了编码膜外区域SeABCB3-OM,并构建了原核表达载体pET30a-SeABCB3-OM,成功表达38kDa的重组蛋白;并且Ligandblot及ELISA分析结果显示重组蛋白Se ABCB3-OM能与BtCry1Ab35活化蛋白特异性结合,推测其为BtCry1Ab35蛋白的受体蛋白。实时荧光定量PCR(quantitative Real-time PCR,qRT-PCR)结果表明,SeABCB3在甜菜夜蛾的各龄期和不同组织中均有表达,其中在卵期和马氏管的表达量最高;本研究克隆获得甜菜夜蛾SeABCB3基因,分析了各龄期及组织结构的表达情况,明确了Se ABCB3蛋白与BtCry1Ab35蛋白的结合特性,为进一步深入研究Bt Cry蛋白对甜菜夜蛾的杀虫作用机制提供了基础。

甜菜夜蛾(Spodopt eraexigua Hübner)雄蛾触角对雌蛾性信息素的EAG反应

采用 EAG生测技术研究表明 ,甜菜夜蛾雄蛾触角上具有 4种性信息素组分 (Z9,E1 2 - 1 4∶Ac(A)、Z9- 1 4∶ OH (B)、Z9- 1 4∶ Ac(C)和 Z9,E1 2 - 1 4∶ OH(D) )的感受细胞。单一组分 A,二元组分 AB和 AD,三元组分 ABC、ABD和 ACD及四元组分 ABCD的 EAG反应显著较高 ,与 3头雌蛾性信息素腺体浸提液的反应强度相当。进一步对 AB二元混合物中两组分的最佳比例以及最佳比例的剂量反应进行了测定。当 AB间的比例为 5∶ 5时可产生最大的 EAG反应 ,其它比例 (9∶ 1、7∶ 3、3∶ 7、1∶ 9)间无明显差异。 AB(5∶ 5)混合物的使用剂量在 0 .0 4～ 4μg范围内 ,EAG值随剂量增加呈直线上升 ;使用剂量低于 0 .0 4μg或高于 40μg。

唑虫酰胺对甜菜夜蛾亚致死效应及解毒酶活性的影响

为明确唑虫酰胺对甜菜夜蛾的亚致死效应以及甜菜夜蛾对唑虫酰胺的生化抗性机制,本研究在测定10种药剂对甜菜夜蛾室内毒力的基础上,研究了唑虫酰胺LC_(10)、LC_(30)和LC_(50)浓度对甜菜夜蛾生长繁殖和解毒酶活性的影响及甜菜夜蛾的生化抗性机制。结果表明,高浓度处理组(LC_(50))的甜菜夜蛾成虫寿命、羽化率和卵孵化率等均显著低于对照组,低浓度唑虫酰胺(LC_(10))诱导了甜菜夜蛾谷胱甘肽S-转移酶(GST)和羧酸酯酶(CarE)活性的上升,显著抑制了多功能氧化酶(MFO)的活性;增效试验表明,增效醚(PBO)和磷酸三苯酯(TPP)对唑虫酰胺有明显的增效作用。抗性种群的CarE、MFO和GST酶活都显著高于敏感种群。综上,低浓度的唑虫酰胺对甜菜夜蛾的生长发育有显著的抑制作用,MFO、CarE和GST在甜菜夜蛾对唑虫酰胺的抗性中发挥了重要作用。

不同地区甜菜夜蛾解毒酶活性测定和酶抑制剂的增效作用

本研究测定了广州白云(BY)、武汉黄陂(HP)、上海崇明(CM)、阜阳界首(JS)4个甜菜夜蛾Spodoptera exigua田间种群和敏感种群多功能氧化酶(MFO)、谷胱甘肽S-转移酶(GST)和羧酸酯酶(CarE)酶活性,发现4个田间种群的3种酶活性中仅MFO酶活性均显著高于敏感种群。采用浸叶法测定了MFO抑制剂胡椒基丁醚(PBO)对BY和HP两个田间种群已产生抗性的药剂的增效作用,结果表明PBO分别与高效氯氰菊酯、甲维盐和氯虫苯甲酰胺混用时,对BY和HP种群均有显著增效作用。进一步以这3种制剂最高推荐用量分别与PBO两个浓度(100 mg/L和50 mg/L)混用进行室内盆栽药效试验,与各自单剂最高推荐用量相比,PBO浓度在100 mg/L和50 mg/L时均对高效氯氰菊酯有显著增效作用,PBO浓度在100 mg/L时对甲维盐和氯虫苯甲酰胺有一定增效作用。本研究结果为制定有效的甜菜夜蛾抗药性治理策略提供了技术支撑。

甜菜夜蛾核型多角体病毒颗粒剂制备及其抗逆性能评价

甜菜夜蛾核型多角体病毒(SeNPV)具有专一性和高效性,可以有效控制甜菜夜蛾种群,而且对环境和生态安全。为了提高甜菜夜蛾核型多角体病毒的稳定性,以海藻酸钠为包埋材料,通过优化载体用量和进料速率等条件,采用喷雾法制备了病毒颗粒剂,并对其相关性能进行了表征和评价。结果表明:海藻酸钠质量浓度为1%,进料速率为13mL/min时制备的病毒颗粒剂呈不规则形状,颗粒剂产率79.4%,病毒含量1.0×10^(6)PIB/g,D_(50)在130μm左右。经颗粒剂海藻酸钠包埋的甜菜夜蛾核型多角体病毒具有良好的热稳定性和抗紫外性能,同时不会影响其对甜菜夜蛾幼虫的致病力。

Median Lethal Concentration Determination of Verticillium lecanii MZ041024 Strain against 2nd Instar Larvae of Laphygma exigua

[ Objective] In order to offer foundation for further study and exploration of the strain against pests, the pathogenicity of V. lecanfi MZ041024 strain against L. exigua was proved. [ Method] Under different spore concentrations of V. lecanii MZ041024 strain, the pathogenicity against 2^nd instar larvae of Laphygma exigua was determined using dipping method. [ Result ] The results showed that LC.50of V. lecanfi MZ041024 strain against 2M instar larvae of L. exigua under the concentration of 4.5 ×10^5 -4.5 ×10^8 spores/ml were 1.367×10^7, 3.245×10^6, 3.202 ×10^5 and 7.803 × 10^4 spores/ml. [ Conclusion] V. lecanfi MZ041024 strains had strong pathogenicity against L. exigua, so it had better control effect on L. exigua.