Influence of mixed biocide GCSC-BtA on the pupae and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host. Plutella xylostella (L.) (Lep., Plutellidae)

This paper deals with the influence of the mixed biocide GCSC-BtA on the pupal and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host, Plutella xylostella (L.) (Lep., Plutellidae). The results show that mortalities of the pupae of P. xylostella in the direct-dip bioassay were 84.67%, that of the adults in the residue bioassay at 1.2500mg/ml concentration of GCSC-BtA were 78.00% which were significantly higher than the mortality values for the pupae with 54.62% and adults with 48.13% of A. plutellae. In contrast, cypermethrin showed extremely high toxicity to the pupae with 94.58% and adults with 86.00% mortality values of A. plutellae as compared to the low mortality values of 42.14% for the pupae and 32.11% for the adults of P. xylostella, with the same concentrations and bioassay methods. The LC₅₀ values of GCSC-BtA were 0.3402, 0.5516 and 1.2405, 1.9480mg/ml for the pupae and adults of P. xylostella and A. plutellae, respectively, while the LC₅₀ values for cypermethrin were 1.5652, 2.3471 and 0.1096, 0.1152mg/ml, respectively. GCSC-BtA was found more toxic to the pupae and adults of P. xylostella and safer to the pupae and adults of A. plutellae than cypermethrin. The possibilty of using GCSC-BtA against P. xylostella under partial control by A. plutellae in vegetable fields is discussed.     

Influence of mixed biocide GCSC-BtA on the pupae and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host. Plutella xylostella (L.) (Lep., Plutellidae)

This paper deals with the influence of the mixed biocide GCSC-BtA on the pupal and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host, Plutella xylostella (L.) (Lep., Plutellidae). The results show that mortalities of the pupae of P. xylostella in the direct-dip bioassay were 84.67%, that of the adults in the residue bioassay at 1.2500mg/ml concentration of GCSC-BtA were 78.00% which were significantly higher than the mortality values for the pupae with 54.62% and adults with 48.13% of A. plutellae. In contrast, cypermethrin showed extremely high toxicity to the pupae with 94.58% and adults with 86.00% mortality values of A. plutellae as compared to the low mortality values of 42.14% for the pupae and 32.11% for the adults of P. xylostella, with the same concentrations and bioassay methods. The LC₅₀ values of GCSC-BtA were 0.3402, 0.5516 and 1.2405, 1.9480mg/ml for the pupae and adults of P. xylostella and A. plutellae, respectively, while the LC₅₀ values for cypermethrin were 1.5652, 2.3471 and 0.1096, 0.1152mg/ml, respectively. GCSC-BtA was found more toxic to the pupae and adults of P. xylostella and safer to the pupae and adults of A. plutellae than cypermethrin. The possibilty of using GCSC-BtA against P. xylostella under partial control by A. plutellae in vegetable fields is discussed.     

寄主密度、寄生蜂密度和寄生蜂性比对麦蛾茧蜂繁殖的影响

麦蛾茧蜂是鳞翅目昆虫的一种外寄生蜂,是仓储鳞翅目害虫的重要寄生性天敌。为提高麦蛾茧蜂的扩繁效率,本文在室内条件下研究了其寄主烟草粉螟密度、麦蛾茧蜂密度和性比对其子代出蜂数(雌蜂数、雄蜂数和总蜂数)和雌雄性比的影响。结果表明,当烟草粉螟密度为5头/盒时,麦蛾茧蜂的子代出蜂雌蜂数、雄蜂数、总蜂数和雌雄性比最高,分别为(90.71±2.01)、(51.70±2.95)、(142.00±3.88)头和(1.79±0.11);当烟草粉螟密度为50头/盒而麦蛾茧蜂密度不同时,4对寄生蜂(蜂与害虫比为1∶12.5)的平均单雌出蜂数最高;此外,增加雌蜂数显著提高子代出蜂数,而增加雄蜂数并未显著影响这些指标。因此,本文推荐在麦蛾茧蜂的大量饲养中,按寄生蜂、害虫比为1∶5~1∶12.5、寄生蜂雌雄性比为1∶1的方式接蜂且可连续使用10 d,这将有利于麦蛾茧蜂的大量饲养。该研究结果可为麦蛾茧蜂的规模化繁育和应用提供技术参数。     

Control of the Whitefly Trialeurodes vaporariorum Westw. (Homoptera, Aleyrodidae) on tomato by the new insecticide Acetamiprid

The efficacy of a new class of insecticide (chloronicotinyl) Mospilan 20 SP (a.i. acetamiprid), compared with Lannate 90 SL (a.i. methomyl) and Applaud WP 25 (a.i. buprofezin), in glasshouse control of whitefly (Trialeurodes vaporariorum) on tomatoes, was investigated. All investigated insecticides significantly decreased the number of whitefly larvae, compared with untreated plots where population density grew during the trial. Based on statistical analysis, efficacy of all insecticides on whitefly larvae were in the same category. Some differences occurred 7 days after the third treatment. Deposited egg number was significantly different between checks and each insecticide plot. Efficacy of investigated insecticides, evaluated according to deposited egg number, was also good and in the same category.     

Evaluation of effectiveness of Insegar (fenoxycarb 250 g/kg) WP against Phyllocnistis citrella Stainton (Lep., Gracillariidae) and its effect on Cales noacki How. (Hym., Aphelinidae)

Aiming to control the citrus leafminer Phyllocnistis citrella St. while at the same time protecting the biological equilibrium and mainly the beneficial insect Cales noacki, experiments have taken place in the regions of Argolis and Fthiotis, Greece in 1996 and 1997. Insegar (fenoxycarb) 2 5 WP was applied on young citrus trees. During 1996, the compound, applied every 10 days at a rate of 30 g/hI (with or without adjuvant), gave satisfactory protection from P. citrella without substantially harming C. noacki populations. No phytotoxicity symptoms were observed during the experiments.     

Evaluation of effectiveness of Insegar (fenoxycarb 250 g/kg) WP against Phyllocnistis citrella Stainton (Lep., Gracillariidae) and its effect on Cales noacki How. (Hym., Aphelinidae)

Aiming to control the citrus leafminer Phyllocnistis citrella St. while at the same time protecting the biological equilibrium and mainly the beneficial insect Cales noacki, experiments have taken place in the regions of Argolis and Fthiotis, Greece in 1996 and 1997. Insegar (fenoxycarb) 2 5 WP was applied on young citrus trees. During 1996, the compound, applied every 10 days at a rate of 30 g/hI (with or without adjuvant), gave satisfactory protection from P. citrella without substantially harming C. noacki populations. No phytotoxicity symptoms were observed during the experiments.     

三种寄主植物对小菜蛾实验种群特征的影响

为明确萝卜、白菜和油菜对小菜蛾实验种群特征的影响,测定了小菜蛾对3种寄主的取食量,通过构建两性生命表比较了不同寄主植物对其实验种群发育与繁殖的影响,并综合生命表与取食量参数,评价了小菜蛾对萝卜、白菜和油菜的危害。结果显示:小菜蛾幼虫在萝卜、油菜和白菜上的取食量差异显著,分别为93.3、105.0和114.7 mg/头。小菜蛾取食萝卜、白菜和油菜后,其幼虫的发育历期差异显著,依次为8.6、8.5和7.6 d;种群内禀增长率依次为0.18、0.23和0.23,周限增长率为1.19、1.26和1.26,净生殖率为18.7、46.1和30.6。取食萝卜的小菜蛾各发育阶段的存活率最低。小菜蛾对各供试寄主实际危害量占理论危害量的百分比为油菜(71.8%)白菜(70.8%)萝卜(53.0%)。表明同一时间内,小菜蛾对油菜危害程度最大,白菜次之,萝卜最小。     

Spring aphid-parasitoid (Hom., Aphididae, Hym., Braconidae) associations and interactions in a Mediterranean arable crop ecosystem, including Bt maize

Conspecific and heterospecific associations of aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) were used to determine the interactions between crops forming the main arable crop ecosystem (wheat, alfalfa, isogenic and [Bt Bacillus thuringiensis] transgenic maize) in an irrigated area in Catalonia, Spain. Species composition and instars of parasitized aphids (mummies) were used to detect the parasitoid population movements between the crops and proved interactions (alternation) between the crops, including transgenic maize. Parasitoid interactions were species-dependent, appearing in the movements between alfalfa-wheat-maize in the individual species. Aphidius ervi Hal., A. rhopalosiphi DeSt.-Perez, A. uzbekistanicus Luzh., Lysiphlebus testaceipes (Cress.) and Praon volucre (Hal.) were classified as key-stone species in the target agroecosystems in the area. No differences were found in aphid-parasitoid associations on Bt transgenic maize and isogenic maize for aphid species composition and associated parasitoid guild.     

Functional responses of the parasitoid,Ertmocerus longipes Compere (Hym., Aphelinidae) to densities of the whitefly,Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleyrodidae) at different temperatures

The present study dealt with the functional responses of the parasitoid,Eretmocerus longipes Compere (Hym., Aphelinidae) to the densities of the whitefly,Aleurotuberculatus takahashi David et Subramaniam (Hom., Aleurodidae) at different temperatures under the laboratory conditions. The results showed that when the initial densities ofA. takahashi-3rd instar were raised from 10 to 320 ind./leaf, the numbers of parasitized nymphs increased as well, ranging from 7.0 to 23.1 at 20°C, 9.8 to 42.9 at 25°C, 6.7 to 39.9 at 30°C, and 1.8 to 8.3 ind./leaf at 35°C, respectively. The Holling Disk Equation was introduced to build up the models of functional responses. The response curves remained type II, although the numbers of parasitized nymphs were significantly different under different temperatures. The suitable initial densities of the host whitefly for parasitization were about 80 individuals per leaf. A negative relation was observed between the initial densities of the whitefly and the parasitization rates by the parasitoid. An increase in the initial densities ofA. takahashi-3rd instars ranging from 10 to 320 ind./leaf resulted in a decrease in the parasitization rate byE. longipes ranging from 70.0% to 7.2% at 20°C, 98.0% to 13.4% at 25°C, 67.0% to 12.5% at 30°C and 18.0% to 2.6% at 35°C with a value of 0.2877 was significantly smaller than that at 20°C with a vlaue of 1.3354, that at 25°C with a value of 1.6465 and that at 30°C with a value of 1.1199, respectively (p<0.01). The handling time (Th) forE. longipes was 0.1521 at 35°C, significantly longer than 0.0510 at 20°C, 0.0289 at 25°C and 0.0320 at 30°C, respectively (p<0.01). The maximum loading number (K) of the parasitized nymphs with a value of 34.5 ind./leaf at 25°C was similar to that with a value of 31.2 ind./leaf at 30°C, about 1.8 times as high as that with a value of 19.6 ind./leaf at 20°C and 4 times more than that with a value of 6.6 ind./leaf at 35°C. It was suggested that temperature affected the functional response by balancing searching rate and handling time. The optimal temperature range for the functional responses ofE. longipes to the densities ofA. takahashi-3rd instar was 25° to 30°C.     

草间钻头蛛共生菌多样性测定及沃尔巴克氏体感染对宿主发育历期和性比的影响

为了解草间钻头蛛Hylyphantes graminicola体内共生菌的组成及共生菌对宿主的影响,通过高通量测序技术确定其体内的优势共生菌,采用常规PCR法对草间钻头蛛进行优势共生菌的感染检测,并研究了优势共生菌感染对草间钻头蛛子代的发育历期和性比的影响。结果表明:经高通量测序细菌16S r DNA的V3、V4区,确定草间钻头蛛的优势共生菌为沃尔巴克氏体Wolbachia和Cardinium。167头被检测蜘蛛中,Cardinium的感染率为100.00%,沃尔巴克氏体的感染率为38.92%。感染沃尔巴克氏体的草间钻头蛛F1代雌蛛的2龄期、3龄期、4龄期和总历期均极显著低于未感染的草间钻头蛛,感染沃尔巴克氏体的草间钻头蛛F1代雌蛛1龄期显著低于未感染的F1代个体,感染和未感染沃尔巴克氏体的草间钻头蛛F1代雌蛛的卵期和5龄期均无显著差异。感染沃尔巴克氏体后,草间钻头蛛F1代雄蛛的1龄期和总历期极显著缩短,2龄期、3龄期和5龄期显著缩短,而卵期和4龄期与未感染沃尔巴克氏体的F1代雄蛛之间无显著差异。另外,沃尔巴克氏体感染极显著提高了草间钻头蛛的子代性比。     

不同花色菊花品种上西花蓟马种群密度及雌雄性比

为明确不同花色菊花品种上西花蓟马Frankliniella occidentalis发生情况及种群变化规律,利用蓝色粘虫板调查了大棚种植的7种单色(黄色、橙色、白色、绿色、粉色、紫色、红色)以及4种双色(黄绿、黄红、白绿、黄白)菊花品种上不同时期西花蓟马的种群密度及雌雄性比。结果表明,根据四分位法得到西花蓟马的发生早期与菊花苗期重合,主要发生期与菊花开花期重合,发生晚期为切花后生长期。在所有单色菊花品种中,西花蓟马在黄色菊花品种上的种群密度最高,主要发生期虫口密度达19.98头/板;且雌雄性比最大,为5.85,显著高于其它单色菊花品种上的雌雄性比。在所有双色菊花品种中,黄绿菊花品种上的西花蓟马种群密度最高,主要发生期虫口密度达26.89头/板,显著高于其它双色菊花品种上数量,且雌雄性比也最大,为6.87。菊花开花是导致西花蓟马种群迅速上升和种群中雌虫比例迅速增加的主要原因,且西花蓟马偏好为害与黄色花色相关的菊花品种。     

泽兰实蝇寄生对紫茎泽兰生长和防御能力的影响

为明确泽兰实蝇Procecidochares utilis寄生对紫茎泽兰Ageratina adenophora生长及防御能力的影响,在温室内设置泽兰实蝇寄生与未寄生紫茎泽兰2组盆栽处理,测定泽兰实蝇寄生对紫茎泽兰生长特性、生物量、叶片营养物质、次生代谢物质和保护酶的影响。结果表明,泽兰实蝇寄生显著降低了紫茎泽兰的株高、茎粗、叶片厚度和叶片数,分别显著降低了24.80%、16.86%、42.31%和27.82%;同时,地上生物量、根部生物量和总生物量分别显著降低了58.89%、54.29%和57.60%。泽兰实蝇寄生还导致紫茎泽兰的营养成分发生显著变化,其中可溶性蛋白、可溶性糖、可溶性淀粉和叶绿素含量分别显著降低了41.18%、11.75%、34.57%和29.96%。泽兰实蝇寄生改变了紫茎泽兰的保护酶活性,其过氧化氢酶和超氧化物歧化酶活性分别比未寄生植株显著升高了59.36%和108.06%,过氧化物酶活性降低了25.69%;同时使紫茎泽兰单宁酸含量显著降低了21.67%,总酚和类黄酮的含量分别显著上升了1.21倍和2.09倍。泽兰实蝇寄生的紫茎泽兰总生物量与次生代谢物质总酚和类黄酮的含量呈显著负相关,相关系数r分别为-0.06和-0.43,对照组则不存在相关性。表明泽兰实蝇寄生可能促使紫茎泽兰改变自身的生长与防御能量分配,减少了营养和生长的投入,将更多的资源投向繁殖和防御。     

Insecticide susceptibility of surviving Cotesia plutellae (Hym: Braconidae) and Diaeretiella rapae (M'Intosh) (Hym: Aphidiidae) as affected by sublethal insecticide dosages on host insects

The effects of sublethal dosages of insecticides applied to Plutella xylostella L. (Lepidoptera: Yponomeutidae) and Lipaphis erysimi Kaltenbach (Homoptera: Aphidiidae) on the insecticide susceptibility of the surviving endoparasitoids, Cotesia plutellae Kurdjumov (Hymenoptera: Braconidae) and Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae), were studied in Shangjie, Minhou, China. The susceptibility to methamidophos and the sensitivity of acetylcholinesterase (AChE) to methamidophos and dichlorvos in the adults of host insects were substantially lower than those in the two parasitoids. The host insects were treated with sublethal dosages of methamidophos in P. xylostella and of methamidophos and avermectin in L. erysimi. The cocoon formation in the two parasitoids decreased significantly, from 35.0% (control) to 13.0% (with methamidophos treatment) for C. plutellae; from 20.6% (control) to 9.0% (with methamidophos treatment) and from 24.3% (control) to 16.7% (with avermectin treatment) for D. rapae. The susceptibility to methamidophos of the resultant emerging adults of the two parasitoids was found to be significantly lower than that of the control when the parasitoids were left in contact with the same dosages of methamidophos. The average AChE activity inhibition by methamidophos and dichlorvos in 34-60 adults of the two parasitoids that emerged from the treatments (15.1% and 31.8% respectively for C. plutellae, and 21.1% and 26.9% for D. rapae) was also significantly lower than those of the controls (55.4% and 48.3% respectively for C. plutellae, and 42.9% and 51.7% for D. rapae). The bimolecular rate constant (k(i)) values of AChE to methamidophos and dichlorvos in the adults of parasitoids without the insecticide treatment were 1.78 and 1.56 times as high as those that emerged from the host insects treated with methamidophos for C. plutellae, and 1.91 and 1.66 times as high as those in the case of D. rapae. It is suggested that there is a difference in AChE sensitivity to insecticides between the resultant emerging parasitoids with and without insecticide pretreatment. Furthermore, the introduction of the insecticides to the host insects could be an important factor in the insecticide resistance development of the endoparasitoids. The natural selectivity would favour the parasitoids that had developed an insensitivity to the insecticide(s).     

Studies on diets and population dynamics of the cigarette beetle Lasioderma serricorne F. (Col., Anobiidae)

Aromatic spice crops such as coriander, Coriandrum sativum L., and fennel, Foeniculum vulgare L., are among the major seeds exported to the international market. Observations on the stores of these crops revealed differences in their susceptibility to the cigarette beetle, Lasioderma serricorne (F.) (Col., Anobiidae). Coriander seeds proved to be the most appropriate diet for the beetle. The population dynamics of L. serricorne (F.) was determined, showing 3 generations during the period from May to October.     

Studies on diets and population dynamics of the cigarette beetle Lasioderma serricorne F. (Col., Anobiidae)

Aromatic spice crops such as coriander, Coriandrum sativum L., and fennel, Foeniculum vulgare L., are among the major seeds exported to the international market. Observations on the stores of these crops revealed differences in their susceptibility to the cigarette beetle, Lasioderma serricorne (F.) (Col., Anobiidae). Coriander seeds proved to be the most appropriate diet for the beetle. The population dynamics of L. serricorne (F.) was determined, showing 3 generations during the period from May to October.     

Infection of Tomicus piniperda (Col., Scolytidae) with Canningia tomici sp. n. (Microsporidia, Unikaryonidae)

Canningia tomici sp. n. (Microsporidia, Unikaryonidae) infects the midgut epithelium, the gut muscules, Malpighian tubules, connective tissues, adipose tissues and the gonads of the pine shoot beetle, Tomicus piniperda (L.) (Coleoptera, Scolytidae). The infection is present in populations of Tomicus piniperda in Europe and in the United States. Uninucleate oval single spores occur in two sizes: 2.8±0.4× 1.4±0.4m and 3.8±0.3×2.0±0.2m. The polar filament of this microsporidium is fixed subapically in a flat anchoring disc. The thick posterior lamellae of the binary polaroplast are asymmetric due to the lateral fixation of the polar filament.     

Infection of Tomicus piniperda (Col., Scolytidae) with Canningia tomici sp. n. (Microsporidia, Unikaryonidae)

Canningia tomici sp. n. (Microsporidia, Unikaryonidae) infects the midgut epithelium, the gut muscules, Malpighian tubules, connective tissues, adipose tissues and the gonads of the pine shoot beetle, Tomicus piniperda (L.) (Coleoptera, Scolytidae). The infection is present in populations of Tomicus piniperda in Europe and in the United States. Uninucleate oval single spores occur in two sizes: 2.8±0.4× 1.4±0.4m and 3.8±0.3×2.0±0.2m. The polar filament of this microsporidium is fixed subapically in a flat anchoring disc. The thick posterior lamellae of the binary polaroplast are asymmetric due to the lateral fixation of the polar filament.     

适度饥饿浅黄恩蚜小蜂对烟粉虱和温室白粉虱的寄生和取食选择

为评价释放前经历饥饿对浅黄恩蚜小蜂Encarsia sophia(GiraultDodd)寄生取食粉虱能力的影响,以3龄Q隐种烟粉虱Bemisia tabaci Q和温室白粉虱Trialeurodes vaporariorum若虫为寄主,在2种粉虱单独或同时存在的情况下,比较释放前经适度饥饿、初羽化未饥饿和初羽化喂饲蜂蜜水3种处理的浅黄恩蚜小蜂对2种粉虱寄主的寄生和取食选择情况。结果表明,在2种粉虱单独存在时,经适度饥饿6 h的浅黄恩蚜小蜂寄生的烟粉虱和温室白粉虱显著多于其它处理,而且能取食更多的温室白粉虱,经适度饥饿的寄生蜂在24 h内通过寄生和取食杀死烟粉虱和温室白粉虱的总量分别为12.5头和12.9头。在2种粉虱同时存在时,适度饥饿寄生蜂取食2种粉虱的总量明显高于其它处理,但不同处理间无显著差异,适度饥饿寄生蜂通过寄生和取食杀死2种粉虱的数量最多为11.5头,显著高于未饥饿处理的6.5头。表明释放前经历适度饥饿可以明显提高浅黄恩蚜小蜂寄生和取食粉虱若虫的能力。