Effect of botanicals on the population dynamics ofNephotettix virescens, rice tungro disease incidence and yield of rice

Leaf extracts ofVitex negundo L,Synadenium grantii Hook. f. andProsopis juliflora (SW) DC, and cake ofAzadirachta indica A. Juss. were evaluated for their efficacy in reducing the population of the green leafhopper,Nephotettix virescens (Distant), and its transmission of rice tungro virus under field conditions. All four plant species tested reduced the population of the vector significantly in both the nursery and main field. The lowest population of the vector was recorded with application of neem cake at 5 kg/0.032 ha of nursery, followed by foliar spray of neem seed kernel extract at 5% in the main field. Rice tungro disease incidence was also less in this treatment, with maximum grain yield of 3580 kg/ha in ‘Kharif’ (July-Oct.) and 3257 kg/ha in ‘Rabi’ (Nov.-March) seasons, and a cost:benefit ratio of 1:3.9 in both seasons. However, the maximum cost:benefit ratio of 1:5.6 and 1:5.8 in Kharif and Rabi seasons, respectively, was recorded withV. negundo.     

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’.     

Antifeedant activity of fruit and seed extracts ofMelia azedarach andazadirachta indica on larvae ofSesamia nonagrioides

Methanolic extracts of seeds and fruits of the chinaberry tree,Melia azedarach L. (Meliaceae), showed strong antifeedant activity against 2nd instar larvae ofSesamia nonagrioides Lefèbvre (Lepidoptera: Noctuidae), a very serious pest of maize(Zea mays L.) in Mediterranean countries. Extracts were applied in an artificial diet at concentrations of 1000 and 2000 ppm. The parameters used to evaluate the activity were larval growth rates; quantity of food ingested; phagodepression/phagostimulation index; quantity of frass produced; quantity of material ingested; duration of larval development; and cumulative mortality. Seed extract showed high bioactivity at both doses, while fruit extract proved to be less active, and only at the higher dose used (2000 ppm) did it display a slight antifeedant activity. The activity of theM. azedarach seed extract at the higher dose (2000 ppm) was comparable to that of pure azadirachtin applied at a dose of 1.25 ppm, or to ‘Mubel’, a commercial extract ofAzadirachta indica A. Juss. (Meliaceae), applied at a dose of 75 ppm.     

Elimination of in vitro bacterial contaminants in shoot cultures of ‘MRS 2/5’ plum hybrid by the use of <Emphasis Type="Italic">Melia azedarach</Emphasis> extracts

The antimicrobial activity of leaf and callus extracts of Melia azedarach was tested on in vitro shoot cultures of the peach rootstoch ‘MRS 2/5’ (Prunus cerasifera × Prunus spinosa) that were heavily contaminated with Sphingomonas paucimobilis (Sp) and Bacillus circulans (Bc). The extracts were filter-sterilised and added at 0%, 1%, 5%, 10% and 20% to a modified Murashige and Skoog proliferation medium previously autoclave-sterilised. Up to about 17% shoots died with 10–20% extract, except for Sp-contaminated shoots, whose survival was reduced to 50% after treatment with 20% extract. No shoots died with 1% to 5% supplement. The undiluted leaf extract showed bactericidal activity on plated Sp and Bc isolates. The homogenates of shoots randomly collected from treated cultures were processed for bacterial colony counting. Thus the 10% supplement was the best treatment for ridding Bc-contaminated cultures of bacteria (although 5% had a similar bactericidal effect), and allowing shoot growth and proliferation comparable to controls at the fifth subculture on a standard medium, while 20% extract was needed to eliminate Sp, and could induce higher growth and proliferation rates in surviving shoots than in untreated cultures. Callus extract was ineffective. The bactericidal activity of the leaf extract seemed attributable to a synergistic effect of azadirachtin with other unidentified compounds present in the extract.     

Powdered neem seed and cake for management of the banana weevil,cosmopolites sordidus, and parasitic nematodes

Field trials were conducted in Kenya with ‘Nakyetengu’, an East African highland banana cultivar (AAA-EA), highly susceptible to banana pests. Regardless of soil fertility levels, incorporation around the plant base of powdered neem(Azadirachta indica A. Juss.) seed or cake at 60-100 g/mat at 4-month intervals, gave better control of the banana weevil,Cosmopolites sordidus (Germar), and of parasitic nematodes, than that achieved with soil application of Furadan 5G (carbofuran) at 60 g/mat at 6-month intervals. Compared with untreated control, fruit yield in most of the neem treatments was significantly higher, particularly during the second cycle of crop production. Neem application conferred a net economic gain, whereas Furadan application proved uneconomical. Application of powdered neem seed or cake at higher rates (200–400 g/mat) at 6-month intervals caused phytotoxicity, resulting in drying up of banana plants before fruiting, or in ‘chokethroat’,i.e., inflorescence emergence failure.     

Neem (Azadirachta indica) seed kernel extracts and azadirachtin as oviposition deterrents against the melon fly (Bactrocera cucurbitae) and the oriental fruit fly (Bactrocera dorsalis)

Neem(Azadirachta indica A. Juss.) seed kernel (NSK) extracts,viz., NSK aqueous suspension (NSKS), ethanolic extract of NSK (EtOH. NSK), hexane extract of NSK (neem oil), ethanolic extract of the hexane extract (EtOH. oil) and acetone extract of deoiled NSK powder (Acet. DNSKP) at 1.25-20% concentrations, and pure azadirachtin at 1.25-10 ppm, were evaluated as oviposition deterrents toBactrocera cucurbitae (Coq.) andB. dorsalis Hendel. NSKS at ≥5% under choice test conditions, and at all concentrations (≥1.25%) in no-choice tests significantly deterred oviposition in both species. Similarly, EtOH. NSK was significantly active at all the concentrations tested for both species in choice and no-choice tests. However, with neem oil and EtOH. oil sensitivities of the two species differed considerably. Both extracts deterred oviposition byB. cucurbitae at all the concentrations tested under both choice and no-choice test conditions. On the other hand, withB. dorsalis, neem oil was significantly deterrent only at 20% in both test regimes and at 5% and 20% for EtOH. oil under choice and no-choice test conditions, respectively. Acet. DNSKP significantly deterred oviposition by both species at all concentrations tested. Azadirachtin failed to deter oviposition in either species.     

Host genotype- and temperature-dependent colonizationof In vitro carnation callus cultures byFusarium oxysporum f.sp.dianthi race 2

Differentin vivo resistance/susceptibility levels of 14 carnation cultivars toFusarium oxysporum f.sp.dianthi race 2, the causal agent of Fusarium wilt disease of carnation, were also expressed in anin vitro system and assayed as the degree of fungal colonization of callus cultures at 20° C. Temperature influenced thein vitro expression of carnation resistance. An incubation temperature of 27° C increased the colonization of calli derived from both the susceptible (‘Corrida’ and ‘Ambra’) and the resistant (‘Pulcino’ and ‘Pallas’) cultivars. At 15°C, the colonization of calli derived from Pulcino and Pallas diminished significantly more than for Ambra and Corrida. Inhibition of fungal growth on resistant calli was correlated to retardation in hyphal development. Both scanning electron microscopy and light microscopy observations showed that hyphae did not penetrate into carnation cells.     

Spray treatments combined with climate modification for the management of Leveillula taurica in sweet pepper

The effects of several spray and climate treatments on Leveillula taurica were tested under controlled and commercial greenhouse conditions either alone or combined with a climate treatment. Ampelomyces quisqualis AQ10 inhibited the germination of conidia on leaves, but not on glass. Trichoderma harzianum T39 inhibited germination on both surfaces. Neither the examined biological control agents (BCAs) nor the two tested mineral oils (AddQ and JMS Stylet-Oil) affected the viability of conidia. Sulphur drastically limited the germination and viability of L. taurica. In experiments at 15–25°C, AQ10 alone reduced hyphal leaf colonisation at 25°C. T. harzianum T39 significantly reduced leaf colonisation at all temperatures but significantly reduced disease only at 20–25°C. The oils significantly reduced leaf colonisation and sulphur reduced both leaf colonisation and disease at all temperatures. Results were confirmed in an experimental greenhouse. In a field experiment, azoxystrobin, polyoxin AL, neem extract, and T39 were effective; sulphur was superior to them. Under severe epidemic conditions the disease had a negative impact on yield; late fungicide treatments at spring-time were found unnecessary. Chemical sprays applied in alternation was compared with the ‘friendly’ spray regime (alternation of Heliosoufre, T. harzianum T39 + JMS Stylet oil, A. quisqualis AQ10+AddQ oil and Neemgard) in two climates i.e. (i.) day warm climate and (ii.) regular (cool) day climate regimes. In the warm climate, there was no significant difference in the performance of the ‘friendly’ spray regime and the chemical spray regime. However, in the cooler climate, the ‘friendly’ spray programme was not as effective as the chemical spray programme. It was concluded that a change in the greenhouse climate may affect the development of powdery mildew and, at the same time, promote the activity of BCAs and render a pathogen more vulnerable to these control agents, allowing for better disease suppression.     

Induced resistance in cotton seedlings against fusarium wilt by dried biomass of<Emphasis Type="Italic">Penicillium chrysogenum</Emphasis> and its water extract

Dry mycelium (DM) of killedPenicillium chrysogenum and its water extract (DME) were used to induce resistance in cotton plants againstFusarium oxysporum f.sp.vasinfectum (Fov). Results showed that the efficacy of either DM or DME in controlling the disease depends on both the concentration and the mode of application. DM amended to the soil at 0.25–2% (w/w) provided 32–75% protection againstFov. Soil drench with 2–5% DME (w/v) and pre-sowing seed soakage with 5–10% DME provided 51–77% and 28–35% protection against the wilt disease, respectively, whereas no protection was obtained with foliar sprays of 1–10% DME. DM and its water extract had no direct antifungal activity on growth ofFov in vitro, suggesting that disease control with DM or DME resulted from the induction of natural defense mechanisms in the cotton plants. Soil drench with 5% DME was as effective as 2% DM powder in inducing resistance againstFov, implying that the resistance-inducing substances were mostly water-soluble. Four cotton cultivars with various genetic resistance levels againstFov were tested at the seedling stage: two resistant ‘Pima’ cultivars and two susceptible ‘Acala’ cultivars. The level of protection achieved in the two susceptible cultivars with DME was equal to, or higher than, that of the two resistant cultivars treated with water. Innate and induced peroxidase activity in cotyledons or hypocotyls and roots coincided with the level of genetic resistance and DME-induced resistance, respectively. Based on our results, an integrated control strategy ofFov with both genetic resistance and induced resistance is suggested.     

Effect of botanical extracts on the biological activity of granulosis virus against <Emphasis Type="Italic">Pieris brassicae</Emphasis>

A granulosis virus strain infecting Pieris brassicae (PbGV) was isolated from the dry temperate region of northwestern Himalayas as a potential microbial agent for its management. The effect of different botanicals (having insecticidal action against P. brassicae) on the bioefficacy of PbGV was evaluated under laboratory conditions using leaf disc bioassays on cabbage for improving the insecticidal performance of the PbGV. The synergistic action of different botanical extracts was evident in terms of reduction in LC₅₀ values against different botanical extracts. Among different extracts, petroleum-ether extract of neem seed kernel (NSK) when combined with PbGV resulted in maximum reduction of LC₅₀ value (4.39 × 10² occlusion bodies [OBs] ml⁻¹) followed by methanolic extract (7.38 × 10² OBs ml⁻¹) and aqueous extract (9.36 × 10³ OBs ml⁻¹) as compared with PbGV alone (1.85 × 10⁴ OBs ml⁻¹) for 2nd instar larvae of the test insect. These trends were found analogous in cases of 3rd and 4th instars of P. brassicae with different solvent extracts of NSK. The other botanicals evaluated, viz., Eupatorium and Artemesia, also resulted in reduction of LC₅₀ values for 2nd, 3rd and 4th instars as compared with PbGV alone when different extracts were combined with virus for bioassays. The studies suggest that the PbGV in combination with botanical pesticides could be more useful as a bio-pesticide against cabbage butterfly (P. brassicae) in IPM programs.     

Effects of clarified neem oil on growth and aflatoxin B1 formation in submerged and plate cultures of aflatoxigenicAspergillus spp.

An increase of 11–31% of dry mycelial mass was observed along with a slight decrease (5–10%) in aflatoxin Bi production in 5-day-old aflatoxigenicAspergillus spp. submerged cultures containing either 0.5 ml or 1.0 ml clarified neem oil (CNO) in 0.1 % Triton solution. Fungal growth and aflatoxin B₁ production were also determined in potato-dextrose-agar petri plate cultures inoculated with aflatoxigenicAspergillus spp. containing an atmosphere of volatiles emitted from 0.25 ml, 0.5 ml, and 1.0 ml CNO added to the plates. After 5 days’ incubation, fungal radial growth was reduced by 7–29% and aflatoxin B₁ production by 0–67%. GC/MS analysis of the head space volatiles of the CNO indicated that the reduction of fungal growth and aflatoxin B₁ was probably due to low molecular weight hydrocarbons, aldehydes, alcohols, and sulfur compounds emitted at 30°C in the dry culture. These results suggest that volatiles emitted from CNO at 30° C in plate cultures were more fungistatic and consequently inhibited aflatoxin production more than neem oil added in liquid cultures.     

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。     

Control of the mushroom phorid fly, Megaselia halterata (Wood), with plant extracts

BACKGROUND: The most serious insect pest problems affecting the cultivation of mushroom [Agaricus bisporus (Lange) Imbach] in Turkey are mushroom flies (sciarids, cecids and phorids). Mushroom phorid fly, Megaselia halterata (Wood), is the most common insect pest species during April‐October. The aim of this study was to evaluate the potential for eight botanical materials (two commercial neem‐based products and six hot‐water plant extracts) to control M. halterata populations in three successive growing periods. RESULTS: Treatment efficacy was evaluated by assessing adult emergence and sporophore damage rates compared with that of a standard insecticide, chlorpyrifos‐ethyl (positive control). All plant extracts caused significant reductions in the mean number of emerging adults and sporophore damage rates compared with the water‐treated control (negative control). Reduction in adult emergence in both neem treatments, Neemazal and Greeneem oil, was greater than that in the positive control. While Neemazal and Origanum onites L. extract had significantly lower sporophore damage rates than the positive control, there were no significant differences between the chlorpyrifos‐ethyl, Greeneem oil and Pimpinella anisum L. extract treatments. CONCLUSION: The results suggest that both neem products and hot‐water extracts of O. onites and P. anisum may be potential alternatives to conventional pesticides for the control of mushroom phorid fly. Copyright © 2008 Society of Chemical Industry     

Antifeedant activity of solvent extracts of neem seed kernel against Spodoptera litura F. and their persistency against sunlight through encapsulation

Abstract

Different solvent extracts of neem seed kernels were evaluated against Spodoptera litura F. on cauliflower, Brassica oleracea var. botrytis leaves. Based on this evaluation, aqueous extract was dissolved in ethanol, and methanol extract in ethanol, and dissolved parts were designated as fraction I and fraction II, respectively. The extracts having more antifeedant activity were encapsulated to achieve stability against the sunlight. Among the solvent extracts tested at 1.0% concentration, methanol extract provided maximum protection (100%) of the leaves followed by ethanol (98.39%) and aqueous (93.01%) extracts. Fraction I and fraction 11 were equally effective at 0.1 % concentration against S. litura larvae and checked more than 70% of leaf damage. However, such extracts were found to be unstable when exposed to sunlight. The pre‐gelatinized starch‐encapsulated products, viz. ρre‐gel I and pre‐gel II were quite stable and afforded more than 68.0% protection to the cauliflower leaves even after 6 days of exposure to sunlight.     

Effects of a formulation of neem extract on six species of cockroaches (Orthoptera: Blaberidae,Blattidae and Blattellidae)

Margosine-0®, a commercial preparation of neem seed extract, was tested for its effects as a toxicant, growth inhibitor, or repellent against six species of cockroaches —Blatta orientalis L.,Blattella germanica (L.),Byrsotria fumigata Guérin-Méneville,Gromphadorhina portentosa (Schaum),Periplaneta americana (L.), andSupella longipalpa (F.) (Orthoptera: Blaberidae, Blattidae, and Blattel-lidae). Last-instar nymphs of these species fed Lab-Chow® pellets impregnated with neem extract at a rate of 0.5 ml/pellet showed increased mortality and retarded development. All lst-instar nymphs ofB, orientalis, B. germanica andS. longipalpa died after consuming treated Lab-Chow pellets. Topical application of 2 μl of Margosine-0 to the abdomens of last-instarB. orientalis nymphs, as well as injection of 0.5 μl, resulted in reduction of growth and increased mortality. Placing lst-instarB. orientalis nymphs on a surface treated with the neem extract had no notable effect. In a choice test,P. americana adults immediately preferred the pellets treated with 0.5 ml of neem extract, but pint cardboard cartons treated with 1.5 ml extract repelled them.     

Nimbolide is the Principal Cytotoxic Component of Neem-Seed Insecticide Preparations

Several neem-seed extracts, some used for preparing commercial azadirachtin-containing insecticides, are cytotoxic to N1E-115 murine neuroblastoma cells with IC₅₀ values of 20–200 μg extract ml⁻¹ culture medium. Bioassay-directed fractionation by reversed-phase HPLC shows that the toxicity to N1E-115 cells is associated primarily with a single minor component identified by isolation and NMR and MS as nimbolide with an IC₅₀ of 1·5 μg ml⁻¹ (3·2 μM ). The difference in quantity of nimbolide in seven neem extract sources generally correlates with their overall cytotoxicity. Three other limonoids (epoxyazadiradione, salannin and possibly deacetylsalannin) but not azadirachtin, nimbin and deacetylnimbin contribute in small part to the cytotoxicity. Reconstituted neem extract with only nimbolide removed is less cytotoxic than the original extract. It therefore appears that nimbolide is the principal cytotoxic component of the neem extracts examined and that such minor constituents may warrant consideration in safety evaluations.     

Efficacy of crude seed extracts of Annona squamosa against diamondback moth,Plutella xylostella L. in the greenhouse

Experiments were conducted to assess the efficacy of crude seed extracts of Annona squamosa collected from Ambon (Maluku, Indonesia) against larvae of the diamondback moth, Plutella xylostella L., feeding on cabbage. Three greenhouse trials were carried out using aqueous seed extracts and an aqueous emulsion of ethanolic seed extracts. At a concentration of 0.5% (w/v), an aqueous emulsion of an ethanolic seed extract was 2.5 fold more effective than 1% rotenone, a commercial botanical insecticide. Crude aqueous seed extracts showed efficacy comparable to pyrethrum, the most widely used botanical insecticide. Seed extract of A. squamosa is a promising candidate for development as a simple botanical insecticide for local use in rural Indonesia.     

辽细辛提取物对灰葡萄孢菌的抑制效果

采用生长速率法和孢子萌发法测定了辽细辛根的不同溶剂(石油醚、氯仿、乙酸乙酯、乙醇)粗提取物和精油对引起黄瓜灰霉病的灰葡萄孢菌菌丝生长和孢子萌发的作用。结果表明,细辛不同溶剂提取物和精油对灰葡萄孢菌的菌丝生长和孢子萌发均有一定的抑制作用,且对孢子萌发的抑制效果好于对其菌丝生长的抑制效果;石油醚提取物和精油的抑菌效果较好,对菌丝生长的EC₅₀分别为177.44 mg/L和159.98 mg/L,对孢子萌发的EC₅₀分别为173.23 mg/L和125.29 mg/L;试验还显示细辛所含的主要抑菌活性成分易被极性小的有机溶剂所提取。     

Potential allelopathic effects of Mikania micrantha on the seed germination and seedling growth of Coix lacryma‐jobi

The allelopathic potential of Mikania micrantha H.B.K. to affect the seed germination and seedling growth of Coix lacryma‐jobi L. was investigated. Water‐soluble allelopathic substances were found in the water extracts of M. micrantha. The effect of the water extracts on the seed germination and seedling growth of C. lacryma‐jobi was concentration‐dependent. The water extracts from the different plant parts (leaf, stem, and root) of M. micrantha differed in their effect on the germination and seedling growth of C. lacryma‐jobi, with the effect of the leaf extract being the least inhibitory. The malondialdehyde (MDA) content in the C. lacryma‐jobi seedlings increased by 64%, 45%, and 52% of the control with increasing concentrations of the extracts of the root, stem, and leaf (80, 400, and 400 g L^?1, respectively). The extract from the M. micrantha roots significantly increased the catalase (CAT) activity of the C. lacryma‐jobi seedlings (48% and 54% of the control at the concentrations of 20 g L^?1 and 80 g L^?1, respectively). The extracts from the leaves and stems at low concentrations increased the CAT activity, but at high concentrations, the extracts decreased the CAT activity. The extracts from the roots, stems, and leaves at concentrations of 80, 400, and 400 g L^?1 also significantly decreased the peroxidase (POD) activity of the C. lacryma‐jobi seedlings to 27%, 52%, and 34% of the control, respectively. These results indicate that the water extracts of M. micrantha could inhibit the seed germination and seedling growth of C. lacryma‐jobi through the regulation of anti‐oxidase activity, such as POD and CAT in the cells. The growth inhibition of the C. lacryma‐jobi seedlings is probably related to injury after oxidization of the cell membranes with the increase of MDA content.     

Development of real-time PCR systems based on SYBR? Green I and TaqMan? technologies for specific quantitative detection of Phoma tracheiphila in infected Citrus

Real-time PCR assays based on SYBR? Green I and TaqMan? technologies were developed for in planta detection and quantification of Phoma tracheiphila, the mitosporic fungus causing ‘mal secco’ disease on citrus. Primers and a hybridization probe were designed on the basis of the internal transcribed spacer (ITS) region of the nuclear rRNA genes. The real-time PCR assays were compared with a classic isolation method in two separate experiments carried out on 6 and 24 month-old sour orange seedlings, artificially inoculated with a conidial suspension of the pathogen. Both technologies made it possible to follow the progression of infection by P. tracheiphila, enabling detection and quantification of the target fungus prior to the development of symptoms. The detection limit was 10 copies of the cloned target sequence and 15 pg of genomic DNA extracted from fungal spores. The values of the cycle threshold (Ct) were linearly correlated with the concentration of the target DNA, indicating that the method is suitable as a qualitative and quantitative assay. The presence of non-target fungal DNA had no effect on the specificity of the assay, but resulted in a 10-fold reduction of sensitivity. Total inhibition of the reaction occurred when conidia of the target pathogen were mixed with an organic soil substrate before extracting DNA using the standard protocol, while an alternative purification kit resulted in a significant decrease in sensitivity. Compared to classic methods, real-time PCR proved faster and easier to perform and showed a higher sensitivity. These results suggest that real-time PCR, based on both chemistries, has a great potential for early diagnosis of ‘mal secco’ disease and for quantitative estimation of fungal growth within host tissue.