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.     

Investigations on side-effects of the mixed biocide GCSC-BtA on different predators of Plutella xylostella (L.) (Lep., Plutellidae) in southeastern China

The present paper deals with laboratory studies on side-effects of the mixed biocide GCSC-BtA on Plutella xylostella (L.) (Lep., Plutellidae) and its predators, e.g. Amblyseius longispinosus (Evans) (Acari, Phytoseiidae), Erigonidium graminicola (Sundvall) (Araneae, Linyphiidae), Orius similis Zheng (Het., Anthocoridae) and Coccinella septempunctata L.(Col., Coccinellidae), in comparison to the commercial insecticides, e.g. Abamectin, Tebufenozide, Dichlorvos, Cartap and Lambda-cyhalothrin.The results showed that GCSC-BtA was highly toxic to the 3^rd instar of P. xylostella with 91.18% mortality, followed by Cartap with 84.38%, Abamectin with 78.00%, Tebufenozide with 75.57%, Lambda-cyhalothrin with 63.75% and Dichlorvos with 50.86% mortality. On the other hand, GCSC-BtA was found to be comparatively less toxic to the predators, causing 31.11%, 13.33%, 11.54% and 6.00% mortalities in A. longispinosus, E. graminicola, O. similis and C. septempunctata, respectively. For comparison, the mortalities recorded for Abamectin, Tebufenozide, Dichlorvos, Cartap, Lambda-cyhalothrin were 72.94%, 55.55%, 70.00%, 53.26% and 98.85% in A. longispinosus, 46.51%, 55.10%, 60.00%, 46.00% and 73.68% in E. graminicola, 22.00%, 16.00%, 35.71%, 26.78% and 81.03% in O. similis, 15.55%, 19.64%, 28.00%, 16.66% and 41.79% in C. septempunctata, respectively.     

Investigations on side-effects of the mixed biocide GCSC-BtA on different predators of Plutella xylostella (L.) (Lep., Plutellidae) in southeastern China

The present paper deals with laboratory studies on side-effects of the mixed biocide GCSC-BtA on Plutella xylostella (L.) (Lep., Plutellidae) and its predators, e.g. Amblyseius longispinosus (Evans) (Acari, Phytoseiidae), Erigonidium graminicola (Sundvall) (Araneae, Linyphiidae), Orius similis Zheng (Het., Anthocoridae) and Coccinella septempunctata L.(Col., Coccinellidae), in comparison to the commercial insecticides, e.g. Abamectin, Tebufenozide, Dichlorvos, Cartap and Lambda-cyhalothrin.The results showed that GCSC-BtA was highly toxic to the 3^rd instar of P. xylostella with 91.18% mortality, followed by Cartap with 84.38%, Abamectin with 78.00%, Tebufenozide with 75.57%, Lambda-cyhalothrin with 63.75% and Dichlorvos with 50.86% mortality. On the other hand, GCSC-BtA was found to be comparatively less toxic to the predators, causing 31.11%, 13.33%, 11.54% and 6.00% mortalities in A. longispinosus, E. graminicola, O. similis and C. septempunctata, respectively. For comparison, the mortalities recorded for Abamectin, Tebufenozide, Dichlorvos, Cartap, Lambda-cyhalothrin were 72.94%, 55.55%, 70.00%, 53.26% and 98.85% in A. longispinosus, 46.51%, 55.10%, 60.00%, 46.00% and 73.68% in E. graminicola, 22.00%, 16.00%, 35.71%, 26.78% and 81.03% in O. similis, 15.55%, 19.64%, 28.00%, 16.66% and 41.79% in C. septempunctata, respectively.Cluster analysis was introduced to group the mortalities caused by the treatments into three toxicity groups with the distance of D=4.1. The 1^st group consisted of GCSC-BtA characterized with low toxicity to all the predators tested with 15.49% mortality on average (highest 31.11% and lowest 6.00%). The 2^nd group consisted of Abamectin, Tebufenozide, Dichlorvos and Cartap with moderate toxicity to the predators with 39.96% mortality on average. The 3^rd group included Lambda-cyhalothrin with high toxicity to the predators with 73.83% mortality on average (highest 98.85% and lowest 41.70%). The susceptibility of the pest and its predators to GCSC-BtA and the insecticides is discussed. GCSC-BtA as a biological control agent is recommended for use in the integrated pests control programs in the vegetable fields.     

Pathogenic effects of Xenorhabdus nematophilus and Photorhabdus luminescens (Enterobacteriaceae) against pupae of the Diamondback Moth, Plutella xylostella (L.)

The relationship between Xenorhabdus nematophilus and Photorhabdus luminescens, the bacterial symbionts of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora, against the diamondback moth, P. xylostella (L.), pupae showed the pathogenic capability of P. luminescens to be over that of X. nematophilus. They gave 60 and 40% mortality with LC₅₀ values of 5×10⁴ and 5.5×10⁵ cells/ml, respectively.The number of bacterial cells influences the rate of killing the pupae of P. xylostella and a direct correlation between mortality of the pupae, percentage of deformed adults and the spraying dose with significant differences were observed. An inverse correlation found between the no. of eggs laid/female, percentage of hatching, adult survival and the spraying dose. These bacterial effects have been attributed to different toxic bacterial enzymes which damage the haemocytes and inhibit activation of the humoral immune system of the insect.     

Pathogenic effects of Xenorhabdus nematophilus and Photorhabdus luminescens (Enterobacteriaceae) against pupae of the Diamondback Moth, Plutella xylostella (L.)

The relationship between Xenorhabdus nematophilus and Photorhabdus luminescens, the bacterial symbionts of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora, against the diamondback moth, P. xylostella (L.), pupae showed the pathogenic capability of P. luminescens to be over that of X. nematophilus. They gave 60 and 40% mortality with LC₅₀ values of 5×10⁴ and 5.5×10⁵ cells/ml, respectively.The number of bacterial cells influences the rate of killing the pupae of P. xylostella and a direct correlation between mortality of the pupae, percentage of deformed adults and the spraying dose with significant differences were observed. An inverse correlation found between the no. of eggs laid/female, percentage of hatching, adult survival and the spraying dose. These bacterial effects have been attributed to different toxic bacterial enzymes which damage the haemocytes and inhibit activation of the humoral immune system of the insect.     

田间小菜蛾抗药性监测及毒理机制研究

田间监测结果表明，福州地区小菜蛾Plutella xylostella(L.)已对生产上常用的各类杀虫剂产生不同程度的抗性，从9月至次年5年期间，田间小菜蛾表现出较高水平的抗性，而在8月份则表现出明显低的抗性水平，短期高温和长期低温的环境条件可明显抑制小菜蛾幼虫的AChE和CarE活性，但短期低温的环境条件对小菜蛾幼虫的AChE和CarE活性影响不大，饲养温度的变化不会影响小菜蛾幼虫AChE和Ki值，但在较高的酶与杀虫剂的反应温度下，有机磷对小菜蛾、菜青虫和黄曲条跳甲AChE的抑制作用显著增高，此外，探讨了田间影响小菜蛾抗性水平的环境因素及毒理学机制。     

小白菜次生代谢物质对小菜蛾雌虫行为的调节作用

为明确小白菜次生代谢物质对小菜蛾行为的调节作用,采用热回流法提取小白菜中不同极性物质,利用Y-型嗅觉仪评价这些物质对小菜蛾雌虫行为的调节效应,采用气相色谱-质谱联用仪(GC-MS)鉴定提取物中各化合物的化学结构.结果显示:小白菜不同极性提取物对小菜蛾雌虫行为均有一定的调节作用,其中,低极性物质在高浓度时有引诱效果,高极...     

家蚕的一种微孢子虫对小菜蛾的致病力测定

测定了从家蚕体内分离的一种微孢子虫Vairimorpha sp.对小菜蛾的致病力。室内试验结果表明,当起始侵染期为小菜蛾2龄幼虫,浓度为1×10~6孢子/ml时对当代小菜蛾的致病力最高,幼虫的死亡率可达80.00％～82.67％,蛹死亡率可达50.00％～52.94％,而小菜蛾雌成虫的产卵量由对照的249.64～278.38粒/雌下降到120.56～126.72粒/雌,产卵量下降50％左右;当起始侵染期为3龄幼虫,浓度为1×10~6孢子/ml时,当代幼虫的死亡率只有40.00％～61.33％,与起始侵染期为2龄时相差很大,蛹死亡率和成虫每雌产卵量下降率与起始侵染期为2龄时差异不大。另外,家蚕微孢子虫还可通过垂直传染方式影响下代小菜蛾幼虫的死亡率。     

溴氰虫酰胺对小菜蛾的田间防效及其在花椰菜中的残留与消解动态

通过田间试验研究了溴氰虫酰胺对小菜蛾的田间防效,分析了露地栽培条件下溴氰虫酰胺在花椰菜上的消解动态和最终残留情况。结果表明:田间药效试验中10%溴氰虫酰胺可分散油悬浮剂按推荐高剂量（有效成分21 g/hm2）施药后24 h~7 d对小菜蛾的防效为92.8%~98.3%;按2倍推荐高剂量（有效成分42 g/hm2）施药,溴氰虫酰胺在花椰菜上的消解半衰期为3.86 d,其残留超标风险与田间用药量、用药次数正相关。建议生产中采用10%溴氰虫酰胺可分散油悬浮剂以有效成分21 g/hm2的剂量用药,每季最多施药2次,露地栽培条件下花椰菜上安全间隔期为3 d。     

小菜蛾对阿维菌素的抗性选育及交互抗性研究

用阿维菌素对小菜蛾进行室内抗性汰选,选择压为约杀死种群70％的剂量。连续施药7～8次即表现抗性趋势,汰选至11代,获得抗性指数为80.71的抗性种群(ABM-R)。ABM-R种群对所测试的有机磷杀虫剂乙酰甲胺磷、有机氯类的硫丹、沙蚕毒素类的杀螟丹、氨基甲酸酯类的灭多威、微生物杀虫剂Bt、磺胺脲类衍生物丁醚脲、芳基取代的吡咯杂环化合物虫螨腈和昆虫生长调节剂定虫隆、虫酰肼无交互抗性(R/S为0.73～1.19),而对苯基吡唑类氟虫腈的敏感性却有所上升(R/S为0.22)。增效剂试验显示,PB和唧对ABM-S种群无增效作用,而对ABM-R种群增效作用显著,增效比分别为24.57和13.61,表明多功能氧化酶和羧酸酯酶在抗性机制中可能起重要作用。     

绿薄荷茎和叶的乙醇提取物对小菜蛾拒食和产卵忌避活性的影响

为有效控制小菜蛾的危害,明确绿薄荷对小菜蛾的防治效果,采用95%乙醇对绿薄荷茎和叶进行索式抽提,并测定了茎和叶提取物12.5、25.0和50.0 mg/mL浓度下小菜蛾幼虫的拒食率和成虫产卵忌避活性。结果显示,绿薄荷茎和叶的乙醇提取物对小菜蛾幼虫的拒食和成虫的产卵忌避均有显著作用,提取物浓度越高,拒食率和产卵忌避率越大。当茎和叶提取物浓度为12.5 mg/mL时,小菜蛾的拒食率最低,分别为36.16%和59.81%,产卵忌避率最低,分别为46.18%和57.78%;茎和叶提取物浓度为50.0 mg/mL时,拒食率最高,分别为82.67%和87.15%,产卵忌避率最高,分别为88.29%和98.27%。茎和叶对应的拒食中浓度(AFC_(50))最高分别为18.93 mg/mL和15.97 mg/mL,产卵忌避中浓度(AOC_(50))最高分别为16.38 mg/mL和15.03 mg/mL。     

温度与光照对阿维菌素系列化合物毒力发挥的效应

系统研究了阿维菌素(avermectin)系列化合物在不同温度和光照下对小菜蛾的毒力效应.结果表明,该系列化合物对小菜蛾幼虫毒力在一定温度范围内符合正温度系数规律.阿巴菌素(abamectin)对小菜蛾幼虫的触杀毒力在16～28℃范围内提高了16倍左右,在22～28℃范围内增幅较大;依维菌素(ivermectin)在16～31℃范围内提高了19倍左右,并在22～25℃范围内增幅较大;埃玛菌素(emamectin)在16～31℃范围内提高了10倍左右.胃毒毒力结果表明,阿巴菌素在16～28℃范围内提高了30多倍;伊维菌素在16～31℃范围内提高了近40倍.另外,埃玛菌素表现出了极高的胃毒作用且随温度变化的幅度较大,其毒力在16～28℃范围内可提高1000倍以上.采用正交旋转组合设计方法研究表明,阿巴菌素对小菜蛾的毒力与浓度及施药后无光照时间有正交互关系,而与紫外光照时间和光照强度有负交互关系.     

坡柳种子中坡柳皂苷A的分离鉴定及其对小菜蛾的拒食活性

采用小孔树脂、凝胶SephadexLH-20、反相色谱ODS及制备型高效液相色谱 (Pre-HPLC) 等分离技术,从坡柳Dodonaea viscosa (Linn.) Jacq. Enum. 种子乙醇提取物中分离获得1个活性化合物。通过质谱及核磁共振等波谱技术,鉴定其为新的齐墩果烷型三萜皂苷类化合物21-epoxyangeloyl-15,16,28-tirhydroxy-22-(2-methylbutanoyl)-Olean-12-en-3-(O-α-L-arabinofuranosyl-(1→3)-O-[β-D-glucopyranosyl-(1→2)]-β-D-glucuronide,命名为坡柳皂苷A,英文名dodoneaviscoside A。生物活性测定结果表明,其对小菜蛾Plutella xylostella (L.) 3龄幼虫具有较好的非选择性拒食活性,24 h拒食中浓度 (AFC₅₀) 为207.4 μg/mL。值得进一步研究。     

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。     

虱螨脲亚致死浓度对小菜蛾保护酶系和解毒酶系活力的影响

为阐明虱螨脲对小菜蛾亚致死效应的生化机制,采用室内生物测定法测定了LC_(10)和LC_(25)亚致死浓度处理小菜蛾3龄幼虫1、6、12、24、48和72 h后其体内保护酶系和解毒酶系的活力变化。结果表明:虱螨脲LC_(10)处理对小菜蛾幼虫体内超氧化物歧化酶(SOD)活力表现为早期诱导、后期抑制的作用,而对过氧化物酶(POD)则表现为先抑制后诱导的作用,对过氧化氢酶(CAT)仅在72h时具有诱导作用;LC_(25)处理对SOD表现为诱导-抑制-诱导-抑制的作用,对POD具有抑制作用,而对CAT具有诱导作用。经虱螨脲亚致死浓度处理后,小菜蛾幼虫体内酯酶和多功能氧化酶活力被明显抑制,且基本表现为浓度越高抑制作用越强;而谷胱甘肽S-转移酶(GST)活力仅在处理后1 h被诱导,之后被显著抑制。表明虱螨脲进入小菜蛾幼虫体内后,初期可诱导SOD、CAT和GST活力升高,以适应外界毒害的影响;但随着时间的延长,3种解毒酶活力被抑制,使其难以代谢,从而增强了对小菜蛾的毒性。     

Inhibitory effects of 4-dodecylresorcinol on the phenoloxidase of the diamondback moth Plutella xylostella (L.) (Lepidoptera Plutellidae)

Phenoloxidase (PO) is a key enzyme in the developmental process of insects that is responsible for catalyzing the hydroxylation of monophenols and the oxidation of o-diphenols. In the present investigation, the PO of Plutella Xylostella (L.)(Lepidoptera Plutellidae) was partially purified with 40% saturated (NH₄)₂SO₄ and Sephadex G-100 gel filtration, and the effects of 4-dodecylresorcinol on the monophenolase and o-diphenolase activity of PO were studied. The results showed that 4-dodecylresorcinol could inhibit monophenolase and o-diphenolase activity. In addition, following 4-dodecylresorcinol treatments, the lag time of PO for oxidation of l-tyrosine was obviously lengthened and the steady-state activity was decreased. The inhibitor was found to be competitively reversible with a K_i of 0.201 mM and an estimated IC₅₀ (inhibition concentration showing 50% of the maximum inhibition) of 0.160 mM for monophenolase and 0.369 mM for diphenolase. The ability of 4-dodecylresorcinol to inhibit PO activity may be associated with its ability to directly affect copper at the active site     

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.     

Zur Kenntnis der Blattminen-MotteCameraria ohridella Desch. & Dim. (Lep., Lithocolletidae) anAesculus hippocastanum L. in der Tschenchischen Republik

Cameraria ohridella was recorded first in 1985 in Macedonia. It gradually expanded to north and west and at present it is a serious pest of Horse ChestnutAesculus hippocastanum in the Czech Republic, having been established at about 80 localities. There are 4–5 overlapping generations with sizes of the larvae of 0.4–4.0 mm. The larva develops inside the leaf tissue in the upper parenchym layer of the leaflet and causes a mine, the size of which is broadened with growing larva. First adults start to fly at the end of April. After mating the females lay single eggs on the leaves. Larval development lasts 25–30 days followed by the prepupa I and II. The latter spins a cocoon in which the pupa of the last generation hibernates. The development from L4 to the prepupa lasts for 3–6 days at 22°C. During the summer it is possible to find all larval and prepupal stages in attacked leaves. FourAesculus species:A. parviflora Walk,A. carnea Haey.,A. glabra Walk andA. indica J. Hobb. were found to be resistent toC. obridella. A. lutea H. J. was liftle andA. pavia L. was heavily attacked. The parasitization ofC. o. larvae was very low. Only 2 parasites were found in 1500 mines in the first and second generation ofC. o., and 40 parasites in 1000 mines of the fourth and fifth generation. The highest mortality takes place in moths, eggs and young larvae. It was found in all 4 generation that there were i. m. 50 eggs/leaflet from which i. m. 3 hibernating pupae resulted. Supposing 2 moths (1♀, 1♂)/leaflet emerged in spring which produced 50 eggs (75 eggs/♀—33% moth mortality), the density of eggs in the first generation after hibernating being the same as in the last (fourth) generation before hibernating. As to the whole populations density in this case we can calculate as following: 3 pupae/leaflet on the tree=3000 pupae/leaflets pro m² on the soil=2000 emerging moths pro m²=50,000 moths (25,000 ♀♀) pro tree (namely 25 m² projecting area of the tree crown×2000 moths).