斜纹夜蛾对茚虫威的抗药性汰选及交互抗性测定

为评估茚虫威抗性风险,在室内进行了斜纹夜蛾对茚虫威的抗性选育和交互抗性测定。经过10代6次室内抗性选育,获得了斜纹夜蛾对茚虫威抗性种群,与选育前相比,斜纹夜蛾对茚虫威的敏感性降低了15.63倍。抗性风险评估结果表明,斜纹夜蛾具有对茚虫威产生高水平抗性的风险。交互抗性测定发现,辛硫磷、高效氯氰菊酯和氟虫腈对茚虫威抗性种群的LC50值分别是同源对照种群的1.53、2.42和1.53倍,溴虫腈和灭多威对茚虫威抗性种群的LC50值分别是同源对照种群的0.78和0.96倍,表明茚虫威抗性种群对这几种杀虫剂未产生交互抗性。     

南京小菜蛾对拟除虫菊酯的抗性机制

通过解毒酶活性测定与钠离子通道基因片段的克隆、测序,研究了南京小菜蛾对拟除虫菊酯产生高水平抗性的生化和分子机制。结果表明,南京抗性种群的酯酶和多功能氧化酶O-脱甲基活性分别是敏感种群的1.06和1.16倍,无显著差异;以2,4二硝基氯苯(CDNB)和1,2-二氯-4-硝基苯(DCNB)为底物,南京抗性种群的谷胱甘肽S-转移酶活性分别是敏感种群的0.68倍和1.03倍;进一步利用聚合酶链式反应(PCR)分别从敏感和抗性小菜蛾基因组DNA中扩增出了位于钠离子通道结构域IIS6的232bp和248bp的DNA片段;与敏感种群相比,南京抗性种群钠离子通道基因存在一个保守性点突变,即C突变为T,并导致亮氨酸突变为苯丙氨酸,表明神经不敏感性是南京小菜蛾对拟除虫菊酯产生高水平抗性的主要机制。     

主要农业害虫对茚虫威的抗性现状及其治理策略

茚虫威属于噁二嗪类杀虫剂,与大多数杀虫剂不同的是其进入害虫体内需要经活化代谢转变成N-去甲氧羰基代谢物（decarbomethoxylated metabolite,DCJW）后不可逆地阻断钠通道,进而发挥杀虫活性。茚虫威由于其作用机制不同于常见的使钠离子通道延迟关闭的菊酯类药剂而被广泛用于鳞翅目和一些同翅目、鞘翅目害虫的防治。抗药性是任何杀虫药剂使用后面临的问题,茚虫威也不例外,许多害虫对其产生了不同程度的抗性。昆虫对茚虫威产生抗性的机制包括酯酶活性、谷胱甘肽S-转移酶（glutathione S-transferase,GST）和P450活性的增加以及分子靶标F1845Y、V1848I、L1014P的突变,这些对茚虫威抗性机制的研究基本都是基于抗性种群和敏感种群开展的,需要进一步验证其对抗性研究的贡献度。针对我国田间害虫种群对茚虫威的抗性现状,及时实施对茚虫威有效的抗性治理是迫切的。对于茚虫威的抗性治理除了传统的杀虫药剂轮用、混用外,需要利用其作用机制特点开展抗性治理策略研究。一是充分利用其活化代谢的特点,开展组合药剂的研究应用;二是菊酯类药剂和茚虫威的作用机制均与钠离子通道有关,但是前者是使钠离子通道关闭延迟,而后者是阻断钠离子通道,开展相关基础研究,使菊酯类药剂与茚虫威合理地用于抗性治理中。本文综述了茚虫威的抗性现状、抗性机制与交互抗性、茚虫威的抗性风险评价,针对茚虫威的抗性特点提出了抗性治理策略。     

菊酯类药剂对草地贪夜蛾的毒力及对钠离子通道的诱导特性

为明确菊酯类药剂对草地贪夜蛾Spodoptera frugiperda的防治效果,采用点滴法在室内测定高效氯氟氰菊酯、高效氯氰菊酯、联苯菊酯、溴氰菊酯和茚虫威原药对草地贪夜蛾3龄幼虫的毒力,利用实时荧光定量PCR技术测定3龄幼虫在这5种药剂诱导不同时间下其体内钠离子通道基因片段的表达量变化。结果显示,高效氯氟氰菊酯、溴氰菊酯、联苯菊酯、茚虫威和高效氯氰菊酯这5种药剂处理草地贪夜蛾3龄幼虫24 h后的LD50值分别为74.911、83.280、152.662、179.372、567.250 mg/L;处理48 h后的LD50值分别为18.946、67.874、120.888、132.790、461.635 mg/L;同时发现草地贪夜蛾3龄幼虫钠离子通道基因的表达均呈现不被诱导或诱导下调现象,表明草地贪夜蛾幼虫可通过降低靶标基因的表达量进而减少药剂对其的毒性。表明供试4种拟除虫菊酯类药剂和1种氯虫苯甲酰胺类药剂可作为草地贪夜蛾田间应急防控药剂施用。     

安徽省草地贪夜蛾对杀虫剂的敏感性和靶标突变检测

采用饲料混毒法测定了安徽省6个地区的草地贪夜蛾3龄幼虫对4种常用杀虫剂的敏感性,并对其靶标的抗性突变频率进行检测,以明确2020年迁入安徽省的草地贪夜蛾对杀虫剂的敏感性现状,为后续制定科学防控措施提供依据。结果显示,马鞍山和宿州草地贪夜蛾种群对氟苯虫酰胺分别产生了11.3倍和10.1倍的抗性;而对甲氨基阿维菌素苯甲酸盐、茚虫威和氯虫苯甲酰胺尚未产生抗性。且这4种杀虫剂的靶标基因均未检测到抗性位点突变情况。以上结果表明,6个地区的草地贪夜蛾对甲维盐、氯虫苯甲酰胺和茚虫威均较敏感,在田间防治中仍可轮换使用该类型杀虫剂。部分地区的草地贪夜蛾对氟苯虫酰胺产生了中等水平抗性,因此以后应该减少该药剂的使用频次。     

甜菜夜蛾对氯虫苯甲酰胺抗性种群选育及鱼尼丁受体基因表达特征

为明确甜菜夜蛾Spodoptera exigua对氯虫苯甲酰胺的抗性发展及抗性种群中鱼尼丁受体(ryanodine receptor,RyR)基因的表达量变化,室内采用饲料混毒法进行甜菜夜蛾对氯虫苯甲酰胺的抗性选育,荧光定量PCR技术研究了抗性和敏感种群之间RyR基因mRNA表达量的差异。结果表明,室内选育31代后获得一个抗性倍数为105.60倍的甜菜夜蛾抗性种群,其mRNA表达量在甜菜夜蛾不同发育阶段及抗性种群和敏感种群之间均存在差异,以表达量最低的卵期作为对照,抗性种群中1龄幼虫表达量最高,是卵期的154.58倍;其次是雄性成虫,其表达量是卵期的101.51倍;2~5龄幼虫分别是卵期的59.56、35.35、72.99和19.84倍。抗性种群中1、2和4龄幼虫mRNA表达量分别是敏感种群的5.99、2.79和2.14倍,其余阶段低于敏感种群。表明甜菜夜蛾对氯虫苯甲酰胺的抗药性可能主要表现在幼虫阶段,RyR基因的表达量变化与氯虫苯甲酰胺诱导有关。     

茚虫威对草地贪夜蛾的毒力及解毒酶的诱导作用

茚虫威对鳞翅目害虫幼虫具有卓越的杀虫活性,是替代传统杀虫剂及治理抗药性害虫的理想药剂。为了明确茚虫威对草地贪夜蛾的生物活性及对其主要解毒酶活性的影响,为使用茚虫威科学防治草地贪夜蛾提供参考,本研究采用浸叶法测定了广西南宁草地贪夜蛾种群3龄幼虫对茚虫威敏感性及增效醚(PBO)、磷酸三苯酯(TPP)、顺丁烯二酸二乙酯(DEM)对茚虫威的增效作用;并测定了亚致死浓度(LC_(20))茚虫威对草地贪夜蛾体内MFO、GSTs和CarE酶的诱导作用。结果表明,茚虫威对草地贪夜蛾的LC_(20)、LC_(50)和LC_(90)分别为8.95、20.62 mg/L和73.57 mg/L。DEM、PBO和TPP对茚虫威的增效倍数依次为2.24、2.05和0.50倍。亚致死浓度(LC_(20))茚虫威处理后对3龄幼虫体内GSTs的活性和MFO含量与无药剂处理(CK)相比显著升高(P0.05),而CarE活性无显著变化(P0.05)。本文结果显示,广西草地贪夜蛾仍可以用推荐剂量80 mg/L茚虫威防治,而代谢抑制剂PBO和DEM对茚虫威有明显的增效作用,且GSTs活性和MFO含量在茚虫威诱导后显著升高,初步推测这两种解毒酶可能影响将来草地贪夜蛾对茚虫威的抗药性发展。     

20种杀虫剂对不同龄期不同地理种群草地贪夜蛾的室内毒力测定

为有效防控新入侵的迁飞性害虫草地贪夜蛾, 指导科学用药, 本研究采用饲料表面涂药法测定了13类20种杀虫剂对云南省玉溪市红塔区(红塔种群)、广东省广州市花都区(花都种群)、广西壮族自治区钦州市钦南区(钦南种群)、云南省玉溪市华宁县(华宁种群)、海南省海口市秀英区(秀英种群)5个种群草地贪夜蛾3龄幼虫的毒力; 进而, 以红塔种群为相对敏感种群, 以华宁种群为抗性种群, 测定甲维盐、溴虫氟苯双酰胺、虱螨脲、氯虫苯甲酰胺、杀铃脲、虫螨腈、高效氯氟氰菊酯、茚虫威和氟苯虫酰胺9种杀虫剂对2个种群草地贪夜蛾5龄幼虫的毒力。结果表明, 20种杀虫剂对5个种群草地贪夜蛾3龄幼虫的毒力大小顺序依次为:甲维盐、溴虫氟苯双酰胺＞虱螨脲、杀铃脲、氟铃脲、氯虫苯甲酰胺＞高效氯氟氰菊酯、虫螨腈、多杀霉素＞溴氰虫酰胺、茚虫威、唑虫酰胺＞氟苯虫酰胺、联苯菊酯、甲氧虫酰肼＞毒死蜱、乙酰甲胺磷＞噻虫嗪＞啶虫脒、甲萘威; 9种杀虫剂对2个种群草地贪夜蛾5龄幼虫的毒力大小顺序依次为:甲维盐、溴虫氟苯双酰胺＞氯虫苯甲酰胺＞虱螨脲＞杀铃脲＞虫螨腈＞高效氯氟氰菊酯、茚虫威＞氟苯虫酰胺, 研究结果表明, 甲维盐、溴虫氟苯双酰胺、虱螨脲、氯虫苯甲酰胺4种杀虫剂对草地贪夜蛾3龄和5龄幼虫具有很高的活性, 是防治草地贪夜蛾的理想药剂, 该研究为合理选择有效杀虫剂进行田间防治提供了科学依据。     

广东草地贪夜蛾不同田间种群对4种杀虫剂的抗药性监测

采用饲料浸药法测定了草地贪夜蛾对氯虫苯甲酰胺、多杀霉素、甲氨基阿维菌素苯甲酸盐、虫螨腈的相对敏感基线,并测定了广东省广州、东莞、开平、平远和阳江等5地田间草地贪夜蛾种群对氯虫苯甲酰胺、多杀霉素、甲氨基阿维菌素苯甲酸盐和虫螨腈的抗药性。结果表明：上述4种药剂对敏感草地贪夜蛾种群2龄幼虫的LC₅₀在0.037～0.300 6 mg/L之间。除平远种群对氯虫苯甲酰胺保持敏感外,其余4个种群对氯虫苯甲酰胺抗性在3.51～9.99倍之间,属低水平抗性;阳江和东莞种群对多杀霉素的抗性分别为17.62倍和17.71倍,属中等水平抗性;其他3个种群对多杀霉素抗性在4.69～7.60倍之间,属低水平抗性;除平远草地贪夜蛾种群对甲氨基阿维菌素苯甲酸盐抗性倍数为5.34倍,属低水平抗性外,其他4个草地贪夜蛾种群对甲氨基阿维菌素苯甲酸盐抗性倍数在0.39～1.08倍之间,属于敏感水平;开平草地贪夜蛾种群对虫螨腈的抗性倍数为10.77倍,属中等水平抗性;广州、东莞和阳江草地贪夜蛾种群对虫螨腈的抗性倍数在4.21～8.84倍之间,属低水平抗性;平远草地贪夜蛾种群对虫螨腈的抗性倍数为2.37倍...     

酶抑制剂与防治甜菜夜蛾和斜纹夜蛾杀虫剂的互作效应

采用点滴法比较了甲维盆、虫螨腈.茚虫威、虫酰肼、毒死蟀、灭多威对甜菜夜蛾和斜纹夜蛾3龄幼虫的室内毒力,以及酶抑制剂与防治甜菜夜蛾和斜纹夜蛾杀虫剂的互作效应.结果表明,甲维盐、虫螨腈、茚虫威对2种试虫毒力较高,LC50值介于0.69～16.32μg/g之间;虫酰肼对甜菜夜蛾毒力较高,LC50值为37.66μg/g毒死蜱对斜纹夜蛾毒力较高,LC50值为20.71μg/g.酶抑制剂PBO,TPP,DEM,SV1在甜菜夜蛾和斜纹夜蛾上对虫螨腈和茚虫威均表现为抑制作用,增效比在0.25～0.96之间;而这4种酶抑制剂在甜菜夜蛾上对甲维盐和虫酰肼以及在斜纹夜蛾上对甲维盐和毒死蟀表现为增效作用,除SV1在斜纹夜蛾上对毒死蜱增效倍数高达16.20外,其它组合增效倍数均介于1.22～4.20之间.     

Effects of a lectin-like protein isolated from Acacia farnesiana seeds on phytopathogenic bacterial strains and root-knot nematode

Acacia farnesiana lectin-like protein (AFAL) showed bacterioestatic effects against Xanthomonas axonopodis pv. passiflorae (Gram-negative) and Clavibacter michiganensis michiganensis (Gram-positive), with the latter being more sensitive. This effect is probably due to the ability of AFAL to interact with the bacterial cell wall where we observed that AFAL induced macroscopic change. The maximum bacterial growth inhibition was approximately 78% when incubated with Gram-negative strains, and as high as 92% percent for the Gram-positive one. The antibacterial effect of flavonoids (rutin, quercetin and morin) was also observed using low concentrations against both bacterial strains. Prior incubation of both with AFAL at high concentrations increases the inhibitory effect of flavonoids on bacterial growth. The potential use of AFAL as a control agent against the root-knot nematode Meloidogyne incognita was investigated as well, showing anti-nematode properties involving both egg hatching and motility. In the juvenile second-stage, AFAL showed reduction in larval mobility when measured against a control group. The results suggest that AFAL is effective against M. incognita and could be used as a component of integrated pest management programs. These data also suggest that lectins probably play a role in plant defense not only against invertebrate phytopathogens, herbivores and fungi but also against bacteria.     

枯草芽胞杆菌对离体荔枝果实霜疫霉病、炭疽病的防治效果

为了进一步明确从土壤中筛选得到的拮抗细菌OR-1、OR-2、OR-3、ON-6的分类地位和生防效果,采用形态学观察、理化特性结合分子生物学方法,鉴定这4株细菌皆为枯草芽胞杆菌Bacillussubitilis.拮抗菌对荔枝霜疫霉菌、炭疽菌菌丝生长均具有明显抑制作用,ON-6菌株的发酵液对菌丝生长的抑制率最高,分别为92.34％和70.36％,其次是OR-1菌株.拮抗菌处理组褐变指数均小于对照组以及杀菌剂处理组,且差异达显著水平(P＜0.05),OR-1菌株防褐变效果最好.常温下,拮抗菌发酵液对离体鲜果病害防治效果优于对照组和杀菌剂处理组,其中ON-6菌株的防治效果最佳;4℃低温储藏处理40天后,拮抗菌发酵液处理组的防治效果高于对照和杀菌剂处理组,且差异显著(P＜0.05),以ON-6和ON-3菌株的防治效果最佳.表明拮抗菌发酵液对荔枝鲜果上的霜疫霉菌和炭疽病菌有一定的抑制作用.     

Agrobacterium-mediated transformation efficiency is altered in a novel rice bacterial blight resistance cultivar and is influenced by environmental temperature

Y73 is a progeny of asymmetric somatic hybridization from an elite japonica rice cultivar (Dalixiang) and a wild rice (Oryza meyeriana), which shows high resistance to bacterial blight. It has a similar genetic background to its recurrent parent, Dalixiang, but Y73 has a high resistance to both bacterial blight and Agrobacterium. The transformation efficiency of Y73 was 35.7%, while Dalixiang had higher transformation efficiency (71.2%) under the same co-cultivation temperature (25 °C). These results indicate that the resistance to Agrobacterium tumefaciens in Y73 was linked with its characteristic of bacterial blight resistance, and was obtained from its donor parent, O. meyeriana. Further studies also showed that the resistance to A. tumefaciens was weakened at a lower temperature (20 °C). To study its molecular mechanism, the expression levels of genes associated with Agrobacterium-mediated transformation (OsMPKs, OsVIP1s and OsPR1s) in rice were investigated by Quantitative real-time PCR (qRT-PCR) analysis. The expression levels of OsMPK genes remained unchanged at different temperatures, while all OsVIP1s and almost all OsPR1s were up-regulated and transformation efficiency of Y73 was increased notably when infected by Agrobacterium at 20 °C compared with 25 °C. This study suggests that the bacterial blight resistance genes in Y73 also have an effect on Agrobacterium-mediated transformation and that the response to temperature is associated with the regulation of MAPK/VIP1 defense signaling pathway.     

The effects of Artemisia annua L. and Achillea millefolium L. crude leaf extracts on the toxicity, development, feeding efficiency and chemical activities of small cabbage Pieris rapae L. (Lepidoptera: Pieridae)

The biological effects of two important medicinal plants, Artemisia annua L. and Achillea millefolium (L.) (viz, mortality, growth, and feeding indices as well as enzyme and non-enzymatic activities) were studied on small white Pieris rapae L a deleterious pest of cruciferous plants under controlled conditions (16:8 h L:D at 25 ± 1 °C and 65 ± 5% RH). The LC₅₀ and LC₂₅ values were 9.387% and 3.645% for A. annua L. and 4.19% and 1.69% for A. millefolium (L.), respectively. At the lowest concentration (0.625%), the deterrency was 29.826% and 44.185% for A. annua L. and A. millefolium (L.), respectively. Feeding indices were variously affected with changes in a number of parameters and an increase in larval and pupal duration. The activity level of alkaline phosphatase increased sharply while alanin and aspartate aminotransferases showed a sharp decrease. For non-enzymatic compounds, the amount of glucose and uric acid increased, but total protein and cholesterol decreased. These results indicate that these two medicinal plants might possess potential secondary metabolites that may be useful for controlling potential insect pests.     

Analysis of two acetylcholinesterase genes in Bombyx mori

Two acetylcholinesterases (AChE, EC 3.1.1.7) cDNAs were identified and cloned from silkworm, Bombyx mori. One of those, BmAChE-o cDNA, is comprised of 3197 nucleotides which encode 638 amino acids, having an amino acid sequence homology of 72% with Drosophila melanogaster Ace-orthologous AChE (AO-AChE). In some species, another AChE group based on the sequence, Drosophila Ace-paralogous AChE (AP-AChE) has been recognized in relation to organophosphate- or carbamate-resistance, but there have been few reports of AP-AChE among lepidopteran species. However, we isolated the AP-AChE from lepidopteran silkworm, and cloned full ORF as BmAChE-p, which cDNA consisted of 2465 nucleotides that encode 683 amino acids. The homologies with other AP-AChEs were over 60% when compared. Although silkworm is not a target of pesticides, the genomic information obtained in this study will contribute to insecticide-resistance study on lepidopteran pest species.     

枣镰翅小卷蛾成虫的寄主趋向和产卵选择

采用固相微萃取(SPME)和GC-MS分析研究木枣和酸枣挥发物成分,并测试枣镰翅小卷蛾触角电位(EAG)反应、寄主趋向和产卵选择,以探明枣镰翅小卷蛾的寄主选择机制。结果显示,在萌芽期,木枣和酸枣嫩叶的挥发成分均为罗勒烯、2-甲基-2-菠烯、α-法呢烯和邻苯二甲酸二丁酯4种,但相对含量稍有不同。枣镰翅小卷蛾成虫对木枣和酸枣2种寄主都有强烈的EAG反应,且同一寄主上雌蛾的EAG反应值极显著地高于雄蛾,其EAG值是雄蛾的3.3倍。枣镰翅小卷蛾对木枣表现强烈的趋向反应,而对酸枣的趋向不明显,且雌虫的趋向反应显著高于雄虫。木枣上的产卵量显著高于酸枣,且木枣枣吊上的单雌产卵量为307.9粒,极显著地高于酸枣枣吊上的产卵量(182.9粒)。研究表明,枣镰翅小卷蛾雌蛾在寄主选择中起主导作用,木枣是其嗜好寄主。     

菜豆普通细菌性疫病菌在土壤和植株残体中的越冬能力

为评估菜豆普通细菌性疫病菌地毯草黄单胞杆菌菜豆致病变种或褐色黄单胞菌褐色亚种在土壤及植物残体中的越冬能力,对采自黑龙江、内蒙古、山西、河北及新疆的18块菜豆生产田的20份土壤及14份植物残体样品进行病原菌分离和鉴定。在MT选择性培养基上有12个土壤样品和13个植株残体样品提取液产生典型的类似黄单胞菌菌落。选取29个分离物进行致病性测定,有27个分离物对菜豆品种"英国红"致病。利用地毯草黄单胞杆菌菜豆致病变种和褐色黄单胞菌褐色亚种的特异性引物X4c/X4e及褐色黄单胞菌褐色亚种特异性引物Xf1/Xf2对29个分离物进行多重PCR检测,其中17个分离物为地毯草黄单胞杆菌菜豆致病变种,10个分离物为褐色黄单胞菌褐色亚种。结果表明,菜豆普通细菌性疫病菌可以在黑龙江、内蒙古、山西、河北的一些菜豆种植区的土壤及植株残体中越冬存活。     

两株棒束孢菌的鉴定及其对茶卷叶蛾和茶小卷叶蛾的致病力

为明确分离自茶卷叶蛾和中华大刀螳僵虫的2株虫生真菌的归属及生防潜力,采用形态学特征和rDNA-ITS序列分析其分类地位,测定了其对茶卷叶蛾和茶小卷叶蛾幼虫的致病力,并初步筛选了其最适培养条件.结果表明:2株真菌均为环链棒束孢Isaria cateniannulata,分别命名为ICBS918和ICTL911.在1.0×10⁸孢子/mL浓度下,ICBS918和ICTL911对茶卷叶蛾幼虫的累计校正死亡率均达100%,LT₅₀分别为3.13 d和3.15 d;对茶小卷叶蛾幼虫的累计校正死亡率分别为100%和95%,LT₅₀分别为3.25 d和3.31 d.接菌后8 d,2菌株对茶卷叶蛾幼虫的LC₅₀分别为0.47×10⁵孢子/mL和1.01×10⁵孢子/mL;对茶小卷叶蛾幼虫的LC₅₀分别为2.20×10⁵孢子/mL和1.34×10⁵孢子/mL.2菌株23 ℃下最适生长培养基均为综合马铃薯培养基,最适产孢培养基均为蛋白胨马铃薯葡萄糖琼脂培养基;在萨氏培养基上,菌株ICBS918和ICTL911分别在24~30 ℃及24 ℃时生长速度最快,在27 ℃和21 ℃时产孢量最大.表明2株环链棒束孢对茶卷叶蛾和茶小卷叶蛾幼虫均具有较好的生防潜力,可作为生防菌进行开发和应用.     

Biological and biochemical responses of Biomphalaria alexandrina to some extracts of the plants Solanum siniacum and Artemisia judaica L.

The molluscicidal activity of cold water, boiled water, methanol, ethanol, acetone and chloroform extracts of Solanum siniacum and Artemisia judaica L. plants against Biomphalaria alexandrina snails was carried out. The tests revealed plant’s ethanol extract was more toxic to the snails than the other tested extracts. Therefore, it was tested against snails’ fecundity (M_x), reproduction rate (R₀) and their infection with Schistosoma mansoni miracidia. In addition, biochemical parameters and the activities of some enzymes in tissues of snails treated with the two tested plants were determined. As well, glucose concentration in snails’ hemolymph was evaluated. Exposure of B. alexandrina snails to plant’s ethanol extract led to a significant reduction in their survival and snails’ fecundity, reproduction rate. In addition, it caused a considerable reduction in the infectivity of S. mansoni miracidia to the snails. Also, it caused a reduction in number of cercariae per snail during the patent period and in the period of cercarial shedding. The results revealed that the glucose concentration in hemolymph and Lactate level in soft tissues of treated snails were increased (P < 0.001) while glycogen, total protein, the lipid content and the pyruvate level in snail’s tissues decreased (P < 0.001). The activities of lactic dehydrogenase (LDH), pyruvatekinase (PK) and cytochrome oxidase (CY) enzymes in homogenate of snail’s tissues were reduced (P < 0.001) in response to treatment with the two tested plants while protease (PR) activity increased (P < 0.001). It is concluded that the application of LC₂₅ of ethanol extract of S. siniacum and A. judaica L. may be helpful in snail control as it interferes with the snails’ biology and physiology.     

苏云金杆菌亚致死浓度对美国白蛾及其寄生蜂生长发育的影响

为阐明苏云金杆菌Bacillus thuringiensis(Bt)与白蛾周氏啮小蜂Chouioia cunea Yang的协同作用,分别用103~108孢子/m L的6个Bt浓度处理美国白蛾Hyphantria cunea 2龄幼虫后,通过室内试验测定了Bt对其致死、亚致死效应,及亚致死浓度Bt对寄生蜂子代出蜂的影响。结果表明,浓度106孢子/m L处理组美国白蛾均未能化蛹;而106孢子/m L处理组均能化蛹并羽化,且幼虫发育历期随Bt浓度的增加而延长,平均蛹重在74.92~92.18 mg之间,均高于对照的68.66 mg,但蛹重不呈线性规律变化。当Bt对美国白蛾平均校正死亡率低于17.17%时,幼虫发育历期延迟不明显,但平均蛹重为101.11~124.34 mg,均高于对照;接蜂后能够正常出蜂,出蜂率为33.13%~51.25%,每蛹出蜂量为117.43~143.42头,均显著高于对照。表明用平均校正死亡率低于20%的Bt处理对白蛾周氏啮小蜂的寄生有利,2种生防措施协同作用存在增效潜力。