昆虫保幼激素类似物作为昆虫生长调节剂

昆虫生长调节剂(IGRs)由于具有和常规杀虫剂不同的独特作用方式而受到人们的重视.1972年,Schafer和Wilder将IGR分成昆虫发育抑制剂(IDI)和蜕皮抑制剂(MI)两类.前者包括下面讨论的昆虫激素类似化合物,后者则包括几丁质合成抑制剂.昆虫激素在昆虫发育过程中起重要作用,其中已知的有脑激素、蜕皮激素和保幼激素.脑激素刺激前胸腺释放出蜕皮激素,蜕皮激素(α-蜕皮激素)转化为20-羟基蜕皮激素(β-蜕皮激素),刺激生成新的表皮,从而诱导蜕皮.     

米满防治四代棉铃虫试验初报

20%米满SC（悬浮剂，下同）是美国罗门哈斯公司研制的新型激素类杀虫剂，它通过模拟天然昆虫的蜕皮激素20-羟基蜕皮激素，有选择的促进鳞翅目幼虫过早地蜕皮，从而达到杀虫的目的，国外在蔬菜、果树等作物上已广泛应用，为开发在棉花上的用途，本站去年的四代棉铃虫发生期间进行了田间药效试验，现报道如下。     

N′-苯甲酰基-N-特丁基苯甲酰肼的苯并杂环类似物的合成与生物活性（上）

昆虫生长调节剂是具有生物合理性的杀虫剂 ,其独特的作用方式使其不仅对靶标昆虫具有选择性 ,而且对哺乳动物、鸟类、鱼类等非靶标生物安全无害 ,已成为作物保护的重要工具。几丁质合成抑制剂、拟保幼激素和拟蜕皮激素是三类主要的昆虫生长调节剂。类固醇蜕皮激素 2 0 羟基蜕皮素 (2 0E)调节昆虫的变态和发育 ,促使昆虫蜕皮。 2 0世纪 80年代后期 ,罗姆 哈斯公司首先开发出拟蜕皮激素化合物PH 5 84 9(抑食肼 ) ,其化学名称为N′ 苯甲酰基 N 特丁基苯甲酰肼 (BTBH) ;其后又开发出第一个商品化的鳞翅目害虫专用杀虫剂PH 5 992 (虫酰肼…     

新颖非甾族拟蜕皮剂tebufenozide对各种昆虫的作用

tbebufenozide(代号RH-5992)系新颖非甾族合成拟蜕皮剂,具有昆虫生长调节剂(IGR)作用。其化学结构为N-叔丁基-N′-(4-乙基苯甲酰基)-3,5-二甲基苯酰肼,是以罗姆-哈斯公司的杀虫剂抑食肼(RH-5849)为原型发展而来。据报导,罗姆-哈斯公司的抑食胼对昆虫的蜕皮素受体(EcR)具有刺激作用,能引起昆虫特别是鳞翅目幼虫早熟,使幼体蜕皮致死。抑食肼尽管与天然蜕皮甾族激素分子结构不同,却具有蜕皮甾族激素的活性。这     

非甾醇蜕皮激素抑制剂：IPM和害虫抗性治理的新工具

甾醇昆虫蜕皮激素,20-羟基蜕皮激素(20E),和倍半萜类保幼激素在调控昆虫生长发育和生殖过程中起着中心作用。因此,模仿或抑制这两种激素作用的化合物被寻找来作为安全的第三代杀虫剂。保幼激素类似物发现较早,而20-羟基蜕皮激素的拮抗物类杀虫剂只是最近才发现的。 罗姆-哈斯公司的科学家们已经发现了三种非甾醇蜕皮激素抑制剂,它们都属于二酰基肼类化合物。其中,N-特丁基-N’-(4-乙苯甲酰)-3,5-二甲基苯酰基肼(tebufenozide;RH5992)是最早商品化以名为Mimic,Confirm和Romdan作为鳞翅目特异性的杀虫剂在几个国家使用。最     

非甾醇蜕皮激素类杀虫剂RH-0345

本文介绍了非甾醇蜕皮激素类杀虫剂RH—0345的理化性质，杀虫原理，主要用途，毒性，制备方法，产品剂型，分析方法，结构修饰及应用前景。     

防治鳞翅目类害虫的新颖杀虫剂——环虫酰肼

环虫酰肼(chromafenozide)系由日本化药株式会社和三共株式会社研制开发,是一种新颖的昆虫生长调节剂,属二酰基肼类化合物。环虫酰肼通过它的激素活性破坏昆虫的蜕皮而致效。此种激素活性系由保幼激素及蜕皮激素同时进行调节,从而导致昆虫产生致命性的蜕皮。室内与田间试验表明,环虫酰肼对危害水稻、蔬菜、果树、茶树及其他作物的鳞翅目害虫的幼虫具有出色的控制作用。     

两类昆虫生长调节剂作用机制的比较

两种昆虫生长调节剂——几丁质合成抑制剂和非舀类蜕皮激素类似物虽然都是作用于蜕皮过程，但有着截然不同的作用机制，本文对这两种杀虫剂作用机制的研究进展进行了总结和比较。     

昆虫生长发育调节剂研究的进展

介绍了对昆虫生长发育有抑制作用的苯甲酰基脲类,非萜类保的激素类似的,二酰基肼类（非甾类蜕皮激素拮抗物）以及源于楝科植物的柠檬酸类等化合物作国杀虫剂的商品化发展进程。讨论了这三类化合物对昆虫不同的作用机制,及其产品对害虫的作用活性和特点,对一些新型作用机制的杀虫剂,如昆虫神经肽抑制剂,生化合成酶抑制剂的发展前景也做了展望。     

N''''-苯甲酰基-N-特丁基苯甲酰肼的苯并杂环类似物的合成与生物活性(上)

昆虫生长调节剂是具有生物合理性的杀虫剂,其独特的作用方式使其不仅对靶标昆虫具有选择性,而且对哺乳动物、鸟类、鱼类等非靶标生物安全无害,已成为作物保护的重要工具.几丁质合成抑制剂、拟保幼激素和拟蜕皮激素是三类主要的昆虫生长调节剂.     

米满对几种重要鳞翅目害虫室内生物活性的研究

米满是非固醇结构的蜕皮激素活性的新一代杀虫剂，室内研究表明米满对粘虫、玉米螟、小菜蛾、斜纹夜蛾、棉铃虫均有较好的杀虫活性，其中对粘虫的杀虫效果最好。米满的杀虫作用较慢，5d杀虫效果好于对照药剂氰戊菊酯和辛硫磷，对其药效的评价应在药后5d和7d，米满对玉米螟、粘虫、棉铃虫试虫表现出明显的抑制生长和拒食作用。     

Foliar Phenolics are Differently Associated with Epirrita autumnata Growth and Immunocompetence

The quality of available food may affect insect herbivores directly (via growth and survivorship) and/or indirectly (by modifying insect vulnerability to parasitoids and pathogens). We examined the relationship between different phenolic compounds, belonging to various phenolic groups, in Betula pubescens spp. czerepanovii (mountain birch) foliage and the larval performance of the geometrid Epirrita autumnata (autumnal moth). Direct effects on insect performance were described by pupal weight, developmental rate, and survivorship; indirect effects were described by the encapsulation rate of an implant inserted into the insect hemocoel, a commonly used way to describe insect immune defense. We found profound differences in the effects of different phenolic categories: several individual hydrolyzable tannins were associated positively with larval performance but negatively with level of immune defense, whereas flavonoid glycosides were inversely related to larval survival but showed no association with the larvae immune defense.     

Neutral sterol metabolism in insects

Since they are unable to biosynthesize sterols, many phytophagous and omnivorous insects satisfy their cholesterol requirement by side chain dealkylation of the C-24 alkyl group of dietary C₂₈ and C₂₉ phytosterols. However, not all insects that can dealkylate the phytosterol side chain produce cholesterol. In addition, certain insects,e.g., some Hymenoptera, Hemiptera, and Diptera, are unable to dealkylate the sterol side chain. Although C₂₇ ecdysteroids (molting hormones), which are biosynthesized from cholesterol, are the major ecdysteroids in most insects, many of those species that are unable to dealkylate phytosterols utilize campesterol as a precursor for the C₂₈ ecdysteroid makisterone A. The considerable diversity of steroid utilization between certain insect species makes it difficult to generalize about insect steroid biochemistry. The ability to disrupt certain unique aspects of steroid utilization and metabolism in insects might be exploited for developing new insect control technology. Based on a paper presented at the Symposium on Plant and Fungal Sterols: Biosynthesis, Metabolism and Function, held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

Cucurbitacins: A Role in Cucumber Beetle Steroid Nutrition?

The conditional role of cucurbitacins as phytosteroid supplements, cholesterol precursors, or ecdysteroid antagonists in the spotted cucumber beetle, Diabrotica undecimpunctata howardi, was investigated in two ways: by comparing larval survival and growth rate on cucurbitacin-rich and cucurbitacin-poor squash cultivars of Cucurbita pepo and by manipulating the presence of cholesterol, phytosteroids, and cucurbitacins in an artificial diet and examining the effects on adult survival and fecundity. Larvae that developed on cucurbitacin-rich roots grew significantly faster and survived as well as larvae on cucurbitacin-poor roots. There was no evidence, however, that adults could substitute cucurbitacins in vital phytosteroid roles. Beetles reared on a cucurbitacin-rich, phytosteroid-poor diet laid significantly fewer eggs and died significantly younger than beetles with a full complement of dietary phytosteroids and also laid fewer eggs than beetles with no access to phytosteroids in their adult diet. The data are consistent with the hypothesis that, when the side chain of dietary cucurbitacins can be successfully hydrogenated, these compounds play a nutritional role as substitutes or precursors for structural steroids. In contrast, when the carbon–carbon double bond cannot be hydrogenated, cucurbitacins may become antagonists at ecdysteroid receptors, negatively affecting beetle fitness.     

Biosynthesis and distribution of insect-molting hormones in plants—A review

Insect-molting hormones, phytoecdysteroids, have been reported to occur in over 100 plant families. Plants, unlike insects, are capable of the biosynthesis of ecdysteroids from mevalonic acid, and in several cases the biosynthesis of phytoecdysteroids was also demonstrated to proceedvia sterols.Spinacia oleracea (spinach) biosynthesizes polypodine B and 20-hydroxyecdysone, which is the predominant insect-molting hormone found in plant species. The onset of ecdysteroid production in spinach requires the appropriate ontogenetic development within the plant, which is related to leaf development. In spinach, lathosterol is the biosynthetic precursor to ecdysone and 20-hydroxyecdysone. Phosphorylated ecdysteroid intermediates, particularly ecdysone-3-phosphate, are required during biosynthesis. Polyphosphorylated forms of ecdysteroids are putative regulatory components of the pathway. During spinach development, the 20-hydroxyecdysone is transported from the sites of biosynthesis to the apical regions. An analysis of the physiological data available suggests that different species may synthesize ecdysteroids in various organs and distribute these ecdysteroids to other sites. Annual plants appear to concentrate ecdysteroids in the apical regions, including flowers and seeds. Perennial plants may recycle their ecdysteroids between their deciduous and their perennial organs over the growing season. Further investigations of ecdysteroid biosynthesis and physiology within plants will be required before an acceptable system can be designed to test phytoecdysteroid effectivenessin vivo against insect herbivory. Based on a paper presented at the Symposium on the “Regulation of Biosynthesis and Function of Isopentenoids,” Atlanta, Georgia, May 1994.     

Behavioral and Physiological Effects of Neem (Azadirachta indica) Seed Kernel Extracts on Larval Parasitoid, Bracon hebetor

An aqueous suspension and an ethanolic extract of neem seed kernel (NSK) at 0.3, 0.6, 1.2, 2.5, and 5.0% concentrations were tested for ovipositional deterrency, feeding deterrency, toxicity, sterility, and insect growth regulatory effects on a larval parasitoid, Bracon hebetor. Neither NSK extracts delivered in the food or by contact influenced the B. hebetor oviposition (parasitization). They also did not cause parasitoid sterility through feeding, but they showed feeding deterrent effects for a limited period. Parasitoid eggs and pupae also were unaffected by the extracts tested. The parasitoid larvae, however, were killed by feeding contaminated host larvae and also through contact with neem extracts. Thus, a minimum safety period is suggested for inundative releases of B. hebetor in integrated pest management.     

Combining Mutualistic Yeast and Pathogenic Virus — A Novel Method for Codling Moth Control

The combination of a pathogenic virus and mutualistic yeasts isolated from larvae of codling moth Cydia pomonella is proposed as a novel insect control technique. Apples were treated with codling moth granulovirus (CpGV) and either one of three yeasts, Metschnikowia pulcherrima, Cryptococcus tephrensis, or Aureobasidium pullulans. The combination of yeasts with CpGV significantly increased mortality of neonate codling moth larvae, compared with CpGV alone. The three yeasts were equally efficient in enhancing the activity of CpGV. The addition of brown cane sugar to yeast further increased larval mortality and the protection of fruit against larvae. In comparison, without yeast, the addition of sugar to CpGV did not produce a significant effect. A field trial confirmed that fruit injury and larval survival were significantly reduced when apple trees were sprayed with CpGV, M. pulcherrima, and sugar. We have shown earlier that mutualistic yeasts are an essential part of codling moth larval diet. The finding that yeast also enhances larval ingestion of an insect-pathogenic virus is an opportunity for the development of a novel plant protection technique. We expect the combination of yeasts and insect pathogens to essentially contribute to future insect management.     

The role of phytoecdysteroids in bracken fern,Pteridium aquilinum (L.) Kuhn as a defense against phytophagous insect attack

Analysis of green bracken fronds collected during July, August, and October, 1975, for phytoecdysteroids showed that these compounds occur in only trace amounts (0.25–0.53 g/kg fresh weight [FW]). The effect of ecdysteroids on the feeding behavior of seven species of insect showed that four species were deterred at ecdysteroid concentrations at or above 60 mg/kg FW diet; one species of insect at 6 mg/kg or above, and two species which were not affected at the higher concentrations. It was concluded that the levels of phytoecdysteroids in bracken would not deter insects from feeding on the plant. The previously published data relevant to the possible role of phytoecdysteroids as defense compounds are also discussed.     

Dietary effects of phytoecdysones in the leek-moth,Acrolepiopsis assectella Zell. (Lepidoptera: Acrolepiidae)

Incorporation of certain phytoecdysones (ecdysterone, polypodine B, and ponasterone A) into a semisynthetic artificial diet induces pathophysiological effects in larvae of the leek-moth (Acrolepiopsis assectella Zell., Acrolepiidae). The effects include lethality of the newly hatched, first-instar larvae; special ecdysial failures associated with the appearance of larvae with two head capsules; and developmental anomalies during metamorphosis. The effective range of dietary ecdysteroid, as evaluated by larval mortality, varies from 25 to 250 ppm. The EC₅₀ value is 100 ppm for polypodine B and 130 ppm for ecdysterone. The dietary effects of the phytoecdysones are similar to the previously observed effects caused by the dried flowers, but not leaves, of the leek plant. However, the active compound of the leek flowers is a saponin.