五种昆虫生长调节剂对韭菜迟眼蕈蚊的致毒作用

为明确昆虫生长调节剂对韭菜迟眼蕈蚊幼虫的毒力差异、作用特点和田间控制效果,采用药液定量滴加法比较了5种昆虫生长调节剂对其不同龄期幼虫的毒力、LC50对4龄幼虫生长发育和繁殖的影响,以及药剂致毒的温度效应和盆栽防效。结果表明:5种昆虫生长调节剂对韭菜迟眼蕈蚊2龄和4龄幼虫的毒力均以虱螨脲最高,LC50分别为0.173 mg/L和0.295 mg/L,氟铃脲和氟啶脲次之,均高于对照药剂辛硫磷;而吡丙醚和灭蝇胺低于辛硫磷。5种昆虫生长调节剂以LC50处理4龄幼虫后,虱螨脲、氟铃脲和氟啶脲对其存活幼虫后续发育历期、成虫羽化率和繁殖力的影响较大,尤其是单雌产卵量较清水对照分别降低72.6%、57.8%和58.1%;灭蝇胺也可使成虫产卵量降低;吡丙醚可引起卵孵化率下降。该类药剂对其幼虫的毒力基本不受环境温度的影响;虱螨脲、氟铃脲和氟啶脲7.5、15 g a.i./667 m2处理对当代4龄幼虫的防效较低,但对下一代幼虫的防效可达93%以上;虱螨脲、氟铃脲和灭蝇胺与新烟碱类的噻虫胺混用,可显著提高药剂的速效性,且持续控制作用好。     

Comparative testing of several juvenile hormone analogues in two species of locusts,Locusta migratoria migratorioides and Schistocerca gregaria

Effective treatment with juvenile hormone analogues (JHAs) of early penultimate or early last-instar locust hoppers induces a supernumerary ‘extra’ nymphal instar. These ‘extra’ nymphs, also termed ‘adultoids’, die in the course of, or shortly after, an ‘extra’ moult. Less effective treatment results in imperfect adults with crumpled twisted wings which presumably limit their flight and migratory abilities. Extremely effective treatment leads to death in the next moult. Comparing dose-response relations of (7S)-methoprene, fenoxycarb, pyriproxyfen and a new JHA, R70-1 (ethyl cis-N-{2-[4-(2-hydroxycyclohept-1-ylmethyl)phenoxy]ethyl}carbamate), we revealed that route of administration, instar of the recipient hopper, and species may alter over 1000-fold the ED₅₀ for the same JHA. Locusta migratoria migratorioides is much more susceptible to JHAs than Schistocerca gregaria. The lowest ED₅₀ found to induce adultoids and subsequent death in the ‘extra’ moult was 0·12 μg pyriproxyfen injected in olive oil to early penultimate instar hoppers of L. m. migratorioides (about 0·5 μg g^-1 fresh weight). R70-1 was more active than pyriproxyfen following the more practical topical application to early last-instar hoppers of L. m. migratorioides, 5·9 μg and 46 μg per hopper, respectively (about 10 μg g^-1 and 78 μg g^-1 fresh weight). The high susceptibility of last-instar L. m. migratorioides nymphs to topically applied R70-1 is promising from the practical standpoint. ©1997 SCI     

12种昆虫生长调节剂对东方黏虫的杀虫活性

浸叶法证明,氟幼脲、除虫脲是试验杀虫剂中对黏虫杀虫活性最高的。氟幼脲、除虫脲,氟虫脲和杀铃脲的杀虫活性分别比抑食肼高242、115、58、53倍。     

Persistence of insect growth regulators against the rice weevil,sitophilus oryzae,in grain commodities

Ten insect growth regulators (IGRs): four juvenile hormone analogs (JHAs) — fenoxycarb, MV-678, R-20458 and dofenapyn, and six molt inhibitors (MIs) — triflumuron, chlorfluazuron, hexaflumuron, teflubenzuron, Dowco 439 and flufenoxuron; and the organophosphate malathion, were evaluated for residual activity in stored grain for 2 years against the rice weevil,Sitophilus oryzae (L.). Triflumuron, flufenoxuron, teflubenzuron, chlorfluazuron, hexaflumuron and fenoxycarb, each at a concentration as low as 1 ppm a.i., were superior to 10 ppm malathion throughout the experiment. The six MIs, each tested at 50 and 100 ppm a.i., gave complete control for 2 years. Moreover, a concentration as low as 1 ppm a.i. of triflumuron, teflubenzuron, flufenoxuron and chlorfluazuron had good residual activity for 1 year post-treatment and provided almost complete grain protection during this period. Among the JHAs, fenoxycarb had the best residual activity. It gave almost complete control (96.6%) ofS. oryzae at 10 ppm for 18 months post-treatment. The other JHAs at the four test concentrations failed to produce this level of control. The viability of the wheat grain was not affected by any of the insecticidal treatments, with 90% germination recorded in treated and control, grains at all intervals tested.     

吡丙醚和烯虫酯对嗜卷书虱控制作用的研究

采用饲料混毒法系统测定了吡丙醚和烯虫酯两种昆虫生长调节剂(IGRs)对重要的储藏物害虫嗜卷书虱Liposcelis bostrychophila Badonnel若虫和成虫的致死作用,对若虫发育情况、成虫繁殖力和卵孵化率的影响。结果表明,以吡丙醚和烯虫酯10 mg/kg的混毒饲料饲喂嗜卷书虱2龄幼虫49 d后,若虫的死亡率分别为80.00%和31.11%;取食20、10和5 mg/kg吡丙醚的若虫最长存活天数分别为71.0、98.2和116.4 d,而对照仅11.3 d即全部羽化为成虫;取食20 mg/kg以下烯虫酯混毒饲料的若虫一部分仍可羽化成成虫,而且成虫仍可繁殖后代;取食吡丙醚混毒饲料的若虫,60 d后存活下来的若虫大多以超龄若虫的形式存在,而取食烯虫酯的若虫则很少出现超龄若虫。成虫取食烯虫酯(200 mg/kg)和吡丙醚(40 mg/kg)混毒饲料后7 d,死亡率分别为26.67%和23.33%,成虫产卵量分别是对照的39.77%和26.13%,产卵后15 d,卵的孵化率分别是65.71%和8.69%,而对照仅为93.18%。该项研究表明,采用40 mg/kg吡丙醚和200 mg/kg的烯虫酯对嗜卷书虱虫口数量有明显的控制作用。     

昆虫生长调节剂和绿僵菌对意大利蝗几丁质酶活力的影响

[目的]探明3种昆虫生长调节剂(苯氧威、氟虫脲、灭幼脲)和一种生物农药(绿僵菌189菌株)对意大利蝗3龄蝗蝻几丁质酶活力的影响.[方法]用药剂处理3龄意大利蝗蝗蝻,用分光光度法测定几丁质酶分解几丁质产物N-乙酰氨基葡萄糖的含量.[结果]3种昆虫生长调节剂浓度达到50mg/L时对几丁质酶的抑制作用超过200％;绿僵菌189菌株对意大利蝗几丁质酶活力也有一定程度的抑制,且抑制作用随着孢子浓度的增加而增大,当孢子浓度达到5×107时,意大利蝗几丁质酶的活力仅为3.8U.[结论]昆虫生长调节剂和绿僵菌均抑制意大利蝗几丁质酶活力.     

Pyriproxyfen,a novel insect growth regulator for controlling whiteflies: Mechanisms and resistance management

Pyriproxyfen, a novel juvenile hormone mimic, is a potent suppressor of embryogenesis and adult formation of the sweetpotato whitefly, Bemisia tabaci (Gennadius), and the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). Dipping of cotton or tomato seedlings infested with 0 to 1-day-old eggs in 0.1 mg litre^?1 resulted in over 90% suppression of egg hatch of both B. tabaci and T. vaporariorum. Older eggs were affected to a lesser extent. Exposure of whitefly females to cotton or tomato seedlings treated with pyriproxyfen resulted in oviposition of non-viable eggs. The LC90 values for egg viability of B. tabaci and T. vaporariorum exposed to treated plants were 0.05 and 0.2 mg litre^?1, respectively. Treatment of whitefly larvae with 0.04–5 mg litre^?1 resulted in normal development until the pupal stage; however, adult emergence was totally suppressed. Second instars of B. tabaci exposed to 5 mg litre^?1 pyriproxyfen, excreted honeydew at a level similar to the control level until the fourth instar (pupation), after which a strong reduction was observed. Inhibition of egg-hatch on the lower surface of cotton leaves was observed when their upper surface was treated with 1–25 mg litre^?1, indicating a pronounced translaminar effect. These findings indicate that pyriproxyfen is an efficient control agent of both B. tabaci and T. vaporariorum. The compound has been used successfully for controlling whiteflies in Israeli cotton fields since 1991. Adults of B. tabaci collected from a rose greenhouse and from adjacent cotton fields were monitored during 1991–1993 for their susceptibility to pyriproxyfen. A high level of resistance was recorded in whiteflies collected from a greenhouse after three successive applications of pyriproxyfen. Based on LC50 values, the resistance ratio for egg-hatch suppression was 554-fold and, for adult emergence failure, 10-fold. However, a single treatment of pyriproxyfen in cotton fields during the summer season (according to an insecticide resistance management (IRM) strategy) did not alter appreciably the susceptibility of B. tabaci to this compound. In order to prevent development of resistance, an attempt should be made to restrict its use to one treatment per crop season applied during the peak activity of the pest. Pyriproxyfen can be alternated with other novel compounds such as buprofezin and diafenthiuron for controlling whiteflies in cotton, vegetables and ornamentals as part of integrated pest management (IPM) and IRM strategies. In pyriproxyfen- or buprofezin-resistant strains of B. tabaci or T. vaporariorum, no appreciable cross-resistance was observed among pyriproxyfen, buprofezin and diafenthiuron.     

昆虫神经肽类激素的研究及应用前景

由昆虫脑神经内分泌细胞分泌的神经肽类激素 ,咽侧体活化激素 (allatotropin ,AT)和咽侧体抑制激素 (al latostatin ,AS) ,分别刺激或抑制咽侧体的保幼激素的生物合成 ,从而控制昆虫的生长、发育和变态。利用昆虫神经内分泌的失调 ,使其体内激素水平失调 ,来达到控制害虫的目的。     

Ovicidal activity of juvenile hormone mimics in the bean bug,Riptortus pedestris

Insect juvenile hormone (JH) mimics (JHMs) are known to have ovicidal effects if applied to adult females or eggs. Here, we examined the effects of exogenous JHMs on embryonic development of the bean bug, Riptortus pedestris. The expression profiles of JH early response genes and JH biosynthetic enzymes indicated that JH titer was low for the first 3 days of the egg stage and increased thereafter. Application of JH III skipped bisepoxide (JHSB₃) or JHM on Day 0 eggs when JH titer was low caused reduced hatchability, and the embryos mainly arrested in mid- or late embryonic stage. Application of JHMs on Day 5 eggs also resulted in an arrest, but this was less effective compared with Day 0 treatment. Interestingly, ovicidal activity of synthetic JHMs was much lower than that of JHSB₃. This study will contribute to developing novel insecticides that are selective among insect species.     

Identification of novel juvenile-hormone signaling activators via high-throughput screening with a chemical library

Juvenile hormone (JH) is an insect-specific hormone that regulates molting and metamorphosis. Hence, JH signaling inhibitors (JHSIs) and activators (JHSAs) can be used as effective insect growth regulators (IGRs) for pest management. In our previous study, we established a high-throughput screening (HTS) system for exploration of novel JHSIs and JHSAs using a Bombyx mori cell line (BmN_JF&AR cells) and succeeded in identifying novel JHSIs from a chemical library. Here, we searched for novel JHSAs using this system. The four-step HTS yielded 10 compounds as candidate JHSAs; some of these compounds showed novel basic structures, whereas the others were composed of a 4-phenoxyphenoxymethyl skeleton, the basic structure of several existing JH analogs (pyriproxyfen and fenoxycarb). Topical application of seven compounds to B. mori larvae significantly prolonged the larval period, suggesting that the identified JHSAs may be promising IGRs targeting the JH signaling pathway.     

Toxicity and biochemical study of two insect growth regulators, buprofezin and pyriproxyfen, on cotton leafworm Spodoptera littoralis

Lethal and sublethal effects of two insect growth regulators (IGRs) buprofezin and pyriproxyfen were evaluated on larvae of cotton leafworm Spodoptera littoralis. Activity of chitinase and polyphenol oxidase (PPO) in surviving larvae after treatment was carried out in order to investigate the biochemical influences of these compounds. The compounds were low toxic against the larvae at 0.05, 0.1, 0.25, 0.5, and 1.0-fold of the field application rate. However, the overall mortalities within 6 days of feeding at 2.0-fold were 46.67% and 100% for buprofezin and pyriproxyfen, respectively. Larval weight gain was considerably decreased as concentration increased. Pyriproxyfen showed high antifeedant activity in a concentration-dependent manner, and larvae stopped to eat from the third day with high dose. Conversely, buprofezin did not significantly show antifeedant except with high concentration (3000 mg (a.i.)/kg diet) that gave 80.68%. The high doses of both compounds showed adverse effects on pupae, and emergence of adults. Buprofezin at the recommended dose (1500 mg (a.i.)/kg diet) caused 93.33% pupation and 53.33% emergence of adults. Otherwise, pyriproxyfen caused 21.33% pupation and zere emergence of adults at the recommended dose (75 mg (a.i.)/kg diet) compared to 100% pupation, and 96.30% emergence of adults in the control. Both compounds varied in their influences on chitinase and PPO activity, and these enzymes could have relation with toxicity of buprofezin and pyriproxyfen against S. littoralis larvae.     

Insect growth regulators with hydrazide moiety inhibit strigolactone biosynthesis in rice

Strigolactones (SLs) are carotenoid-derived plant hormones involved in several growth and developmental processes. Also, SLs are allelochemicals that induce the seed germination of root parasitic plants and the hyphal branching of arbuscular mycorrhizal fungi. In this study, to identify novel lead chemicals that inhibit SL biosynthesis, we evaluated the effect of agrochemicals on SL biosynthesis. We found that the diacylhydrazine insect growth regulator, chromafenozide, reduced the endogenous level of 4-deoxyorobanchol (4DO), a major SL in rice. Furthermore, treatment with the same class of insect growth regulator, methoxyfenozide, also resulted in the reduction of 4DO levels in rice root exudates. These results suggest that chromafenozide and methoxyfenozide are novel lead inhibitors of SL biosynthesis.     

昆虫神经肽抑咽侧体素及其类似物的研究进展

抑咽侧体素 (ASTs) 是一类由昆虫脑神经细胞分泌,通过作用于咽侧体进而抑制保幼激素 (JH) 合成与释放的昆虫神经肽。因其具有调控昆虫生长、发育和生殖等生理过程的功能,被认为是一类潜在的害虫控制剂。本文在简介了昆虫神经肽在害虫防治中的应用基础上,综述了昆虫神经肽抑咽侧体素的发现、类别和功能,并结合本研究组的工作,重点介绍抑咽侧体素及其类似物的结构修饰和优化、活性构象及构效关系研究,同时也介绍了抑咽侧体素及其类似物的受体和作用机制研究进展。最后,展望了该领域的未来发展趋势,期望为新的生态友好型农药的研发提供一定的参考作用。     

Mode of action of methoprene in affecting female reproduction in the African malaria mosquito,Anopheles gambiae

BACKGROUND: One of the most studied actions of juvenile hormone (JH) is its ability to modulate ecdysteroid signaling during insect development and metamorphosis. Previous studies in mosquitoes showed that 20‐hydroxyecdysone (20E) regulates vitellogenin synthesis. However, the action of JH and its mimics, e.g. methoprene, on female reproduction of mosquitoes remains unknown. RESULTS: Here, a major malaria vector, Anopheles gambiae Giles, was used as a model insect to study the action of methoprene on female reproduction. Ecdysteroid titers and expression profiles of ecdysone‐regulated genes were determined before and after a blood meal. An ecdysteroid peak was detected at 12 h post blood meal (PBM). The maximum expression of ecdysone‐regulated genes, such as ecdysone receptor (EcR), hormone receptor 3 (HR3) and vitellogenin (Vg) gene, coincided with the ecdysteroid peak. Interestingly, topical application of methoprene at 6 h PBM delayed ovarian development and egg maturation by suppressing the expression of ecdysone‐regulated genes in female mosquitoes. CONCLUSION: The data suggest that ecdysteroid titers are correlated with Vg synthesis, and methoprene affects vitellogenesis by modulating ecdysteroid action in A. gambiae. Copyright © 2010 Society of Chemical Industry     

Effect of plant growth regulators on the shoot gall formation in mango caused by Apsylla cistellata Buckton (Psyllidae: Homoptera) in India

Abstract

Trials were conducted from 1979 to 1983 at Pantnagar on the effect of 2,4‐dichlorophenoxy acetic acid (2,4‐D) (5 to 250 mg/litre), 2,4,5‐trichloroxyphenoxy acetic acid (2,4,5‐T) (5 to 250 mg/litre), 1‐naphthyl acetic acid (NAA) (5 to 500 mg/litre), chlorocholine chloride (CCC) (50,100 mg/litre), naleic hydrazide (MH) (50, 100 mg/litre), abscisic acid (10, 50 mg/litre), gibbrellic acid and Alar (10 and 50 mg/litre) on the gall formation in mango by Apsylla cistellata Guckton. There was no effect on the number of galls formed but abnormal, open, elongated galls were formed in the case of 2,4‐D (100 mg/litre and above) and 2,4,5‐T (150 mg/litre), in which nymphs of A. cistellata could not survive, resulting in control of the pest. No flower panicles emerged on the twigs with no nymphal population.     

昆虫共生菌调控宿主生长发育和生殖的研究进展

共生菌参与昆虫宿主的多种生理活动,而昆虫则为共生菌提供了良好的增殖环境,两者互利共生。共生菌的种类、丰度和功能均因昆虫种类和发育阶段的不同而有所差异。该文总结了昆虫共生菌研究概况及已报道的昆虫共生菌种类,重点介绍了共生菌调控昆虫宿主生长发育和生殖的研究进展,包括共生菌通过协助宿主营养代谢及抵御病原菌来调控宿主的生长发育速率;胞内共生细菌沃尔巴克氏体Wolbachia通过胞质不亲和、雌性化、雄性致死以及诱导孤雌生殖调控宿主的生殖力;胞外共生细菌则通过参与宿主营养代谢、改变宿主生殖行为和影响宿主生殖细胞来调控昆虫宿主的生殖力,以及共生菌调控宿主生殖的可能分子机制。同时,该文还在深入探讨共生菌功能、拓宽研究宿主种类及共生菌在抗菌防虫中的应用等方面进行了展望。共生菌对昆虫宿主生长发育和生殖调控作用的研究有助于进一步揭示昆虫与共生菌的协同进化机制,并为进一步利用共生菌进行害虫治理奠定理论基础。