The production of azadirachtin by in-vitro tissue cultures of neem,Azadirachta indica

Callus produced from leaves of a Ghanaian strain of the neem tree, Azadirachta indica A. Juss has been shown to produce the natural insecticide azadirachtin when grown in a defined medium. The azadirachtin was isolated by standard procedures of solvent partition and column chromatography monitored by supercritical fluid chromatography. Biological activity was monitored with antifeedant tests using the desert locust (Schistocerca gregaria Forsk.). The azadirachtin was identified by chromatography on three independent chromatographic systems (SFC, HPLC & TLC) and two thin-layer colour tests. It has 100% antifeedant activity at < 0.04mg litre^?1. The yield of azadirachtin was 0.0007% based on dry weight of callus.     

Bioactive compounds from neem tissue cultures and screening against insects

Hairy root cultures have been derived from neem (Azadirachta indica A Juss, Family Meliacceae) using Agrobacterium rhizogenes and have been studied for the production of compounds with antifeedant effects on insects. Six-week-old hairy root cultures were extracted, and HPLC yielded fractions ranging from polar to non-polar compounds. High antifeedancy levels against the desert locust were observed in fractions(F) 2, 3 and 4 whilst F1 and F5 were not significantly antifeedant. Interestingly F3 did not contain any of the well-known neem chemicals while F2 contained azadirachtin and 3-tigloylazadirachtol and F4 nimbin and salannin. © 1999 Society of Chemical Industry     

Detection and Elimination of Viruses in Callus, Somatic Embryos and Regenerated Plantlets of Grapevine

The distribution of some grapevine viruses in flower explants, embryogenic and non-embryogenic calli, single somatic embryos and plants regenerated from embryogenic cultures was investigated by RT-PCR and ELISA. Immature anthers and ovaries of the cultivars Grignolino infected by GRSPaV, GLRaV-1 and GVA, Müller-Thurgau infected by GRSPaV and GLRaV-3 and Bosco infected by GRSPaV were cultivated on media inducing indirect somatic embryogenesis. Viruses were detected both in anthers and ovaries. Four months after culture initiation 65.6% of tested calli were infected by at least one virus; high percentages of virus infection were found in calli originating from ovaries. No virus was detected in calli tested 8 months after culture initiation, as well as in single somatic embryos or in embryo-derived plantlets. Somatic embryogenesis confirmed its effectiveness in eliminating phloem-limited grapevine viruses. Regeneration of RT-PCR negative plantlets occurred even when at least a sector of the callus was still infected: the mechanism whereby somatic embryos are freed of some viruses could be related to the rapid proliferation of embryogenic cells within the callus or to the origin of the embryogenic callus from virus-free cells within the original explant.     

<Emphasis Type="Italic">In situ</Emphasis> localization of <Emphasis Type="Italic">Grapevine fanleaf virus</Emphasis> and phloem-restricted viruses in embryogenic callus of <Emphasis Type="Italic">Vitis vinifera</Emphasis>

In grapevine, somatic embryogenesis is particularly effective in eliminating several important virus diseases. However, the mechanism whereby regenerated somatic embryos are freed of the viruses is not clear. The distribution of Grapevine fanleaf virus (GFLV), Grapevine leafroll-associated virus-3 (GLRaV-3) and Grapevine virus A (GVA) in embryogenic callus of grapevine was investigated by in situ hybridization using digoxygenin-labelled oligonucleotide probes. Four months after culture initiation, in callus originated by GFLV-infected explants we observed a mosaic of infected and uninfected cells, with high concentrations of viruses in some cell groups in peripheral zones of the callus. In addition some abnormal somatic embryos showed a high hybridization signal. In callus originated by GVA- and GLRaV-3-infected explants the viruses were concentrated in few cells surrounded by areas of virus-free cells. The two viruses were generally localized in different clusters of cells inside the callus and the levels of infection were lower than those observed in GFLV-infected callus. No virus was detected in callus nor in somatic embryos after 6 months of culture. The results highlight the difficulties of some viruses at stably invading callus tissues and the differential ability of GFLV to spread in the callus cells compared to the phloem-limited viruses.     

Elimination of Citrus psorosis virus by somatic embryogenesis from stigma and style cultures

Somatic embryogenesis was used to eliminate Citrus psorosis virus (CPsV) from three citrus species (common mandarin, sweet orange and Dweet tangor), all of which regenerated somatic embryos with different embryogenic potential from stigma and style explants. CPsV was detected by double antibody sandwich‐indirect‐enzyme‐linked immunosorbent assay (DASI-ELISA) in explants and embryogenic callus, but was not detected in any of the plants obtained from somatic embryos, even 24 months after regeneration. Loss of juvenile characters (disappearance of thorns) was observed in the first year of growth and was retained in plants propagated by grafting from thornless stems. Somatic embryogenesis appears to be a very promising technique for the production of healthy citrus stocks.     

Biological activity of neem against the red pumpkin beetle,Aulacophora Foveicollis

The biological activity of neem on the red pumpkin beetle,Aulacophora foveicollis Lucas, was studied. The effective concentration for 50% antifeedant activity was 0.01% methanolic neem seed kernel extract (NSKE) and 0.4% neem oil, using leaves of muskmelon as feeding substrate. No-choice feeding of adults for a period of 11 days on leaves of muskmelon treated with 0.5-2.0% NSKE led to nearly 50% mortality within 4-7 days, whereas there was no mortality of adults fed on as high as 2% neem oil. The antifeedant activity of NSKE was found to vary with curcurbitaceous hosts. Neem oil as a residual film had an LC₅₀ of 0.7%. Unlike most chemical insecticides, 1% aqueous NSKE was not phytotoxic to the 5-day-old cotyledon stage and to 15- and 35-day-old crop stages of muskmelon, whereas 1% neem oil was toxic to the 5-day-old cotyledon stage and 15-day-old crop of muskmelon, but not to the 35-day-old crop.     

Effect of antifeedants on the diamondback moth (Plutella xylostella) and its parasitoid Cotesia plutellae

Two neem preparations and the bitter‐tasting synthetic chemical denatonium benzoate were tested in the laboratory as antifeedants against the diamondback moth, Plutella xylostella L. The effects of the three materials on Cotesia plutellae (Kurdjumov), a hymenopteran parasitoid of ­P xylostella, were also recorded. All three materials significantly reduced the food consumption of ­P xylostella larvae. Parasitoid cocoons were formed on approximately half of those larvae which had been exposed to female C plutellae, regardless of antifeedant treatment, but emergence of adult parasitoids from the cocoons was significantly reduced by antifeedant treatment. In terms of food consumption and mortality of unparasitised P xylostella larvae, and emergence of adult C plutellae, the effect of each antifeedant preparation was directly related to the concentration of material used, but the effects of the neem preparations were greater than those of denatonium benzoate. However, no adult P xylostella emerged on any antifeedant treatment, therefore some of the parasitoids survived antifeedant treatments which were fatal to the unparasitised hosts. © 2000 Society of Chemical Industry     

Neem kernel as an antifeedant against the tobacco caterpillar (Spodoptera Litura F.)

Phytoparasitica - Laboratory tests showed that neem (Melia azadirachta L.) seed kernel suspension in water at 3% was effective as an antifeedant against all the five instars of the tobacco...     

Activity of glutathione S-transferase toward some herbicides and its regulation by benoxacor in non-embryogenic callus and in vitro regenerated tissues of Zea mays

A procedure was developed to obtain non-embryogenic callus and regenerated lines from root segments of Zea mays grown in aseptic conditions. The activity of glutathione-S-transferases (GSTs), for non-embryogenic callus, was determined toward 1-chloro-2,4-dinitrobenzene (CDNB) and it was compared with that obtained for corn seedlings grown without hormones. For the callus masses, increases of specific activity toward CDNB and the kinetic parameter V_max were observed with respect to corn seedlings. The procedure permitted the regenerating of tissues from callus explants, therefore the GST(CDNB) activity and the effect of the safener benoxacor on its expression were investigated for the regenerated tissues grown in agarized substrate and in liquid medium. These explants showed a constitutive GST(CDNB) activity higher than corn seedlings and this activity was increased, for both tissues, in response to the presence of the safener benoxacor in the growing medium. The GST activity for the above tissues was also assayed toward benoxacor and terbuthylazine, metolachlor and fluorodifen herbicides. Measurable GST activity was found toward some of the above chemicals and it was found to be significantly enhanced in response to benoxacor treatment.     

沙漠蝗灾发生、监测及防控技术进展

沙漠蝗Schistocerca gregaria因其具有强大的繁殖、取食和迁移能力被称之为世界上最具破坏力的害虫之一。本文综述了非洲沙漠蝗灾的发生历史及近年来的发生现状;叙述了沙漠蝗监测预警技术的发展过程及最新进展;同时分析了沙漠蝗的防治技术发展。总结认为蝗灾的物联网智能化监测和可持续绿色防控是未来的发展趋势,将为消除蝗灾威胁和保护生态环境提供保障。     

Use of neem products/pesticides in cotton pest management

Products derived from leaves and kernels of neem (Azadirachta indica A. Jussieu) are becoming popular in plant protection programmes for cotton, mainly because synthetic pesticides have several undesirable effects. Neem derived pesticides have been found to be effective and economic in controlling major cotton pests. Neem products act both as systemic and as contact poisons and their effects are antifeedant, toxicological, repellent, sterility inducing or insect growth inhibiting. Furthermore, neem products appear to be environmentally safe and IPM compatible and have the potential to be adopted on a broad scale, together with other measures, to provide a low cost management strategy.     

应用楝科植物防治柑桔害虫试验

本文应用楝科植物(印楝、川楝、苦楝)种籽油及其抽提物对柑桔木虱及其他害虫进行一系列的忌避拒食及触杀作用试验,证明印楝油有明显的忌避及拒食作用。印楝油对柑桔潜叶蛾有良好的防效。印楝、川楝及苦楝油对柑桔红蜘蛛也有较强的触杀作用。应用楝科植物杀虫剂可兼治几种害虫,对人畜安全,不污染环境,不会引起抗药性的产生,而且对害虫天敌也比较安全。     

沙漠蝗防控技术的综述

沙漠蝗Schistocerca gregaria为重大农业害虫,2020年初至今,沙漠蝗大面积暴发,导致多国进入紧急状态,联合国粮食及农业组织(Food and Agriculture Organization of the United Nations,FAO)号召全球共同应对沙漠蝗灾害。为有效防控沙漠蝗,本研究对沙漠蝗的监测技术、防治策略、防治方法、施药方法与药剂选择等方面进行了综述,并对未来进行了展望,以期为沙漠蝗迁飞为害预防与精准防控提供参考。     

Actions of azadirachtin,a plant allelochemical,against insects

Investigations of the antifeedant mode of action of azadirachtin and four synthetic analogues, 22,23-dihydroazadirachtin, 3-tigloylazadirachtol, 11-methoxydihydroazadirachtin and 22,23-bromoethoxydihydroazadirachtin have revealed that both polyphagous and oligophagous insects are behaviourally responsive to azadirachtin, with the most responsive species being able to differentiate extremely small changes in the parent molecule. In Lepidoptera the antifeedant response is correlated also with increased neural activity of the chemoreceptors. When locusts are treated on crop plants, the antifeedant and physiological actions of azadirachtin and analogues work in concert and result in feeding deterrence, growth and moulting aberrations and mortality with the same order of potency as for antifeedancy. Specific binding studies using [³H]dihydroazadirachtin carried out on locust testes and Spodoptera Sf9 cells have shown that the competitive binding of the different analogues of azadirachtin to these binding sites occurs in a similar order of potency to that found with antifeedant and IGR bioassays. This suggests a causal link between specific binding to membrane proteins and the ability of the molecule to exert biological effects. © 1998 Society of Chemical Industry     

The desert locust,Schistocerca gregaria,and its control in the land of israel and the near east in antiquity,with some reflections on its appearance in Israel in modern times

Locusts and grasshoppers have caused periodic devastations since the very beginning of recorded history and are a threat worldwide until this very day. The most feared of all locusts was (and is) the desert locust,Schistocerca gregaria (Forsk.) (’arbeh’). This review deals with different aspects of man’s interaction with this pest in the Mediterranean and Near East regions as reflected by ancient literature: decorations found in Egyptian tombs (6th Dynasty, 2420-2270 B.C.), in the Har-ra=Hubullu list (Assyria — the Ashurbanipal Royal Library, 669-626 B.C.) and in Biblical, Rabbinical, Greek and Roman literature. The aspects covered herein are those of locust nomenclature, terms used for the development stages (life cycle), outbreaks, plagues and their consequences (famine), locusts as food, etc. Some control measures during Biblical, Grecian, Roman, Mishnaic, Talmudic, Byzantine and modern times (19th and 20th Centuries) are reviewed. Nowadays, the total area invaded during desert locust outbreaks and plagues extends over 29 million square kilometers of desert and subdesert, involving more than 60 nations. Between plagues the ’natural’ locust population occupies an area of approximately 14 million square kilometers of desert and subdesert. An attempt is made to identify various terms for locust in the pre-Biblical, Biblical, Rabbinical, Greek and Roman literature according to modern nomenclature.     

The antifeedant effect of neem seed kernel extract and azadirachtin on nymphs ofEyprepocnemis plorans

Acridids belonging to different species and families exhibit large differences in their response to neem components. In this context the antifeedant effect of a methanolic neem seed kernel extract (NSKE) and of azadirachtin (AZA) on fourth-instar nymphs of the acrididEyprepocnemis plorans Charpentier (Saltatoria:Acrididae) was investigated. Nymphs were offered either saccharose-impregnated filter paper disks or leaves of broad beans, treated with neem components. The amount of substrate consumed was determined by weighing the filter paper or by measuring the leaf area. On filter paper both NSKE and AZA were highly active down to the 10⁻⁴% treatment. In the leaf treatment, however, AZA was definitely more active than NSKE, with 100% deterrence at 10⁻⁴% and 10⁻²%, respectively. The methanolic NSKE was somewhat more active than the commercial preparation ‘Neemark’.     

离体黑果枸杞再生途径的研究

以黑果枸杞的叶片和茎段为外植体,采用MS为基本培养基,研究激素对经历愈伤组织诱导、丛生芽诱导以及叶片直接诱导小植株再生途径的影响。实验结果表明,诱导茎段、叶片形成愈伤组织的适宜培养基分别为MS+2,4-D0.3 mg·L~(-1)、MS+2,4-D0.4 mg·L~(-1),其诱导率均为100%;诱导茎段、愈伤组织分化形成丛生芽的适宜培养基分别为MS+6-BA0.2 mg·L~(-1)+KT0.1 mg·L~(-1)、MS+6-BA0.5 mg·L~(-1),而愈伤组织分化出的丛生芽均发生玻璃化现象,其增殖系数分别为32.3倍、47.1倍;诱导叶片分化形成植株的适宜培养基为MS+NAA0.01 mg·L~(-1),其再生植株诱导率为33.3%。结论:黑果枸杞再生能力强,以上途径均能形成再生植株,其最佳的离体繁殖途径为茎段诱导丛生芽形成再生植株。     

Noxious effects of neem extracts onCrocidolomia binotalis

The potential of neem extracts to control the cabbage webworm,Crocidolomia binotalis Zell. (Lepidoptera: Pyralidae), was investigated in the laboratory. Neem, besides being an antifeedant at as low as 0.001% of the methanolic extract, was shown to be very toxic, as evidenced by high larval mortality and poor emergence. It also caused disruption of normal development: significant delays in larval moults, appearance of permanent larvae in the 3rd and 6th instars, and abnormal pupation. A possible interference with hormonal activity is discussed.     

紫花苜蓿下胚轴愈伤组织诱导及再生植株的研究

以培养4～5d的紫花苜蓿无菌苗的下胚轴为材料,改良SH(SH大量元素+MS微量元素+MS铁盐+UM有机)+水解酪蛋白(CH)2000 mg/L为基本培养基,对紫花苜蓿愈伤组织诱导和植株再生进行了研究。愈伤组织诱导和继代培养基分别为2,4-D 1.0 mg/L+KT 0.5 mg/L+蔗糖30 g/L及2,4-D 0.05 mg/L+BA0.5 mg/L+蔗糖30 g/L,将获得的愈伤组织转入正交设计的培养基上进行筛选,得到了愈伤组织分化率相对较高的培养基配方:基本培养基+KT 0.4 mg/L+蔗糖20 g/L,其分化率为73.0%。获得的再生芽在生根培养基上(1/2MSO)培养约10d便能获得具有根和叶的再生植株。本试验结果为下一步将来自蓝藻的Na⁺/H⁺ an-tiporter基因转入苜蓿,获得转基因耐盐苜蓿奠定了基础。