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1.
Populations of intracellular symbiotes declined significantly in brachypterous females of the brown planthopper,Nilaparvata lugens (Stål), which were stressed during nymphal development by caging them on IR20 rice plants treated with 3% neem oil, 5% neem seed kernel aqueous extract, or 10% neem cake aqueous extract. In addition, nymphs grew poorly and symbiote populations in prospective females declined, when reared on rice plants grown in soil treated with neem cake; this indicates systemic action of bioac-tive neem constituents. Addition of custard-apple oil to neem oil did not enhance the inhibitory effects. The effects of neem derivatives on the symbiotes may be either host-mediated — possibly through disturbed neuroendocrine homeostasis, or direct — leading to perturbations of host-symbiote equilibrium.  相似文献   

2.
A study on the compatibility of the entomopathogenic fungus Beauveria bassiana with neem was conducted against sweetpotato whitefly, Bemisia tabaci, on eggplant. Initially, three concentrations of neem (0.25%, 0.5% and 1.0%) were used to investigate the physiological responses of B. bassiana. Thereafter, above three concentrations of neem along with three concentrations of B. bassiana (106, 107 and 108 conidia/ml) were used to investigate combined deterrence index, DI under two application methods (foliar and soil) of B. tabaci. Significant differences were observed among neem concentrations on all variables- germination percentage, vegetative growth, number of conidia, amount of biomass and proteolytic activity of B. bassiana. The reduction percentage of germination, vegetative growth, sporulation, biomass production and proteolytic activity of B. bassiana were as high as 12%, 13%, 35%, 38%, and 34%, respectively, to neem. Significant differences were also observed on deterrence index, DI (adult and oviposition) of B. tabaci. The current study investigated that the highest adult DI (80.15) and oviposition DI (88.25) occurred when 1.0% neem was combined with 108 conidia/ml of B. bassiana. As the results show, neem is compatible with B. bassiana; and soil application of neem along with foliar application of B. bassiana might be useful for the control of B. tabaci.  相似文献   

3.
The pyrethroid permethrin was shown to be active against Blattella germanica, Periplaneta americana and Blatta orientalis. In laboratory tests on plywood panels the best formulation was a 25% wettable powder which showed an initial LC50 of 10 mg m?2 against B. germanica and lost activity at the weekly rate of 1.9 mg m?2. An initial deposit of 108 mg m?2 gave 50% kill after one year. The synergist piperonyl butoxide diminished residual performance. In one field trial, good control was maintained for more than four months with an initial deposit of 50 mg m?2, the smallest dose used. From this and other trials, the recommended rate of application for general use in long-term control is 100 mg m?2. A distinctive slow expellent action against B. germanica was seen in field trials.  相似文献   

4.
To investigate the effect of botanicals on the foraging behavior of the mealybug predatorCryptolaemus montrouzieri Mulsant, predator larvae and adults were exposed to leaves and the mealybugPlanococcus citri (Risso) treated with one of the following: a crude neem seed extract; a formulation of azadirachtin (Azatin EC®); a pyrethrum extract; and one of two naphthoquinones isolated fromCalceolaria andina Benth. (BTG 504 and BTG 505). All the botanicals influenced the foraging behavior ofC. montrouzieri, at one or more concentrations. Larval and adult foraging behavior was influenced most by BTG 504 and neem also affected larval behavior; the predators contacted fewer treated leaves and spent less time on treated than on untreated leaves. Larvae also consumed fewer mealybugs treated with BTG 504 and BTG 505 compared with untreated mealybugs.  相似文献   

5.
American cockroaches, Periplaneta americana (L.), and German cockroaches, Blattella germanica (L.), ingested large quantities of powder (silica aerogel and boric acid) in the process of preening their appendages. Their crops were greatly distended by the powder, but the denticles of the armarium of the proventriculus permitted the movement of only very small quantities of silica aerogel into the remainder of the alimentary tract. Boric acid likewise passed the armarium in very small quantities and apparently only in solution.There was no significant difference in the rate of mortality of both species of cockroaches confined with deposits of silica aerogel SG-68, whether their mouthparts were sealed with paraffin wax or left unsealed. Ingested powder did not increase the rate of water loss. Cockroaches with unsealed mouthparts died more rapidly on deposits of boric acid than those with sealed mouthparts, as might be expected of a toxic compound. However, cockroaches with sealed mouthparts were strikingly affected by boric acid, indicating cuticular penetration by that compound. Penetration within the integument, in the gross body contents, in the alimentary tract, and in the feces was confirmed by a boric acid flame test.  相似文献   

6.
M. Schmid  U. Guyer 《Gesunde Pflanzen》2004,56(7-8):218-221
We tested a combined application of neem and two predatory mite species, Amblyeius cucumeris and Hypoaspis miles, against a spontaneous infestation of a Western Flower thrips population (Frankliniella occidentalis) under greenhouse conditions. We treated the infested plants and the soil twice at an interval of 8 days with neem solutions of 0.3% and 0.5%, respectively. Four days after the second treatment, we released the two predatory mite species. We monitored the thrips population with blue insect traps and counted the insects caught regularly. From the 21st week (monitored till the 52nd week) after the beginning of the treatment with neem, we registered no further thrips on the insect traps.  相似文献   

7.
Immature stages of two diaspids,Chrysomphalus aonidum (L.) andAonidiella aurantii (Maskell), and two coccids,Saissetia oleae (Olivier) andCeroplastes floridensis Comstock, were sprayed with the insect growth regulator (IGR) RO 13-5223 [ethyl 2(p-phenoxyphenoxy) ethyl carbamate]. Development of first and newly transformed second nymphs of both male and femaleC. aonidum was inhibited at a concentration of 0.0125%; mature 2nd female nymphs were not susceptible to treatment at 0.025%. The chemical did not arrest the development of treated mature 2nd female nymphs ofA. aurantii. When nymphs ofA. aurantii were sprayed with the IGR as 1st and newly transformed 2nd stages, emergence of males was inhibited, while females were markedly less affected. The development ofS. oleae immature stages as well as of 1st and 2nd nymphs ofC. floridensis was completely arrested by RO 13-5223 treatment at a concentration of 0.006%.  相似文献   

8.
Laboratory assays were done to evaluate the effect of neem seed kernel extract (Azadirachta indica A. Juss),Vitex negundo L. (Lamiales: Verbenaceae) leaf extract, andBacillus thuringiensis (Berliner), applied separately or together, on nutritional indices of the rice leaffolderCnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). All three biopesticides suppressed feeding and larval growth and low concentrations affected the larval performance. The combined effect of the three biopesticides resulted in a considerable decrease in nutritional indices, indicating strong deterrence. Dose response relationships were established with respect to frass production and larval growth. The efficiency of conversion of ingested and digested food was considerably reduced.  相似文献   

9.
Two extracts from neem (Azadirachta indica A. Juss. (Meliaceae)) seeds, azadirachtin and oil, and a mixture of neem oil and abamectin, were tested on second-instar nymphs of the rice bugLeptocorisa chinensis (Dallas) (Hemiptera: Alydidae). To clarify the effect of spraying coverage on bioefficacy of test materials, experiments were conducted under choice and no-choice conditions in field cages. In a choice test, treatment with the mixture of neem oil and abamectin was most effective in reducing the survival ofL. chinensis, followed by azadirachtin at 60 ppm, 30 ppm and 3% neem oil, whereas all treatments except neem oil caused 100% mortality within 3 weeks in a no-choice test. When second-instar nymphs had choices of treated and untreated plants within a treatment, no differences in yield and sum of dead and stained grains were found between those two choices, indicating that nymphs neither caused significant reduction in yield nor reduced the quality of untreated plants. Regardless of treatment, the difference in overall yield between treated and untreated plants under choice conditions was not statistically significant (P>0.05). Our results indicate that neem-based formulations, used alone or in combination with abamectin, have the potential to be integrated into the existing programs to control the rice bug. http://www.phytoparasitica.org posting Aug. 28, 2005.  相似文献   

10.
In this study, the effects of two different commercial neem insecticides (NeemAzal T/S and Neem Oil) were determined on different stages of Nezara viridula (L.) (Heteroptera: Pentatomidae) under laboratory conditions. Neem Azal and Neem Oil were applied at concentrations of 0.5 % and 2 %, respectively. Mortality was recorded after 3, 7 and 14 days for nymphs and adults; 7 and 14 days for old (4-day-old) eggs; and 14 days for newly laid (one-day-old) eggs. Both products have no significant effect on adults and newly laid eggs. However Neem Oil was found to be more effective than NeemAzal T/S on nymphs and on old laid eggs after 7 and 14 days. It can be concluded that both neem products have potential for insecticidal efficacy (approximately 60 %) against nymphs of N. viridula. at concentrations recommended by manufacturers for registered pests.  相似文献   

11.
In this study, the effects of two different commercial neem insecticides (NeemAzal T/S and Neem Oil) were determined on different stages of Nezara viridula (L.) (Heteroptera: Pentatomidae) under laboratory conditions. Neem Azal and Neem Oil were applied at concentrations of 0.5 % and 2 %, respectively. Mortality was recorded after 3, 7 and 14 days for nymphs and adults; 7 and 14 days for old (4-day-old) eggs; and 14 days for newly laid (one-day-old) eggs. Both products have no significant effect on adults and newly laid eggs. However Neem Oil was found to be more effective than NeemAzal T/S on nymphs and on old laid eggs after 7 and 14 days. It can be concluded that both neem products have potential for insecticidal efficacy (approximately 60 %) against nymphs of N. viridula. at concentrations recommended by manufacturers for registered pests.  相似文献   

12.
The compatibility and protectant potential of Calneem® oil derived from the neem tree Azadirachta indica and two parasitoids, Habrobracon hebetor and Venturia canescens, for the control of the rice moth Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) and the tropical warehouse moth Cadra cautella Walker (Lepidoptera: Pyralidae) in stored rice and wheat, were evaluated in the laboratory. Calneem® oil (= neem oil) is a biopesticide produced, registered and marketed in Ghana by AQUA AGRIC Community Projects (AACP/Caldor Ghana Ltd., Tema). It contains 0.3% azadirachtin as its major active ingredient. The oil was emulsified with water using 0.07% soap. Fourth instar moth larvae were held in grain treated with neem oil only, grain treated with one of the parasitoids only, grain treated with a combination of neem and one of the parasitoids, and a control with untreated grain. Neem oil was applied at concentrations from 5,000 to 30,000 ppm. All samples were kept in growth cabinets maintained at 25°C and 65–70% r.h. Adult emergence was recorded after 4 weeks. Parasitoid or neem treatments alone reduced the emergence of C. cephalonica and C. cautella. In general, parasitoid releases were as effective as a combination of neem oil and parasitoids. At the lowest dose, 5,000 ppm, the combination of neem and parasitoid was more effective than the neem alone. The number of adults of H. hebetor and V. canescens that emerged in rice containing either parasitoids alone or in combination with neem oil was similar. This indicates minimal or no adverse effect of neem oil on the two parasitoids. It is thus possible to incorporate neem oil in a well-designed pest management program with parasitoids.  相似文献   

13.
Abstract

Aleuroclava jasmini (Hemiptera: Aleyrodidae) is a major insect pest of paper mulberry (Broussonetia papyrifera) in Iran, negatively affecting its production. Considering the importance of oils in the integrated management programs of such pests, the present study examined the possibility of whitefly control on paper mulberry plant to assess mortality rate (MR), synergistic rate (SR), resistance rate (RR), and lethal concentration for 50% of the population (LC50) of oils and common insecticide in populations from four areas of Tehran, Iran (one susceptible and three non-susceptible). The best chemical treatments against A. jasmini adults and nymphs in paper mulberry plants were neem oil (1?ml L?1) mixed with deltamethrin (0.5?ml L?1) or with buprofezin (1?ml L?1). The neem, akylarylpolyglyglycol ether and volk oils mixed with deltamethrin or buprofezin also had synergistic effects on adults and nymphs of A. jasmini, respectively, in Azadi, Shahrake Gharb, and Vanak areas (non-susceptible populations), but with higher concentrations (> LC50) and lower SR than in Garm Dareh area (susceptible population). We observed that A. jasmini adults showed the greatest resistance to deltamethrin in Vanak area and nymphs of this pest to buprofezin in Shahrake Gharb area.  相似文献   

14.
The efficacy and species specifity of two commercial sticky traps (Ekolex-V and Trappit-Lo Line) were compared in field tests in a multistorey restaurant complex in CZ. Traps were tested under high population density ofblatta orientalis L. (BO) andBlattella germanica (L.) (BG). We found species specific differences in trapping efficiency between the two traps. There was a high correlation between visually estimated counts and actual catches of BG and BO in Trappit. The correlation in Ekolex catches was lower (BG: r=0.86, BO: r=0.58). Nymph/adult ratio increased with increasing population density in both Trappit and Ekolex traps. Although both types of traps reflected differences in population density, we found Trappit more efficient than Ekolex especially forBlatta orientalis. Estimated Trappit/Ekolex ratio of BG catches decreased with increasing population density showing Trappit more sensitive. Trapping sensitivity at low cockroach density was proposed as a standard criterion for evaluation of cockroach trap efficiency.  相似文献   

15.
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.  相似文献   

16.
Experiments were conducted to establish if the formation of 2.4-dichlorophenol (DCP) from 2.4-dichlorophenoxyacetic acid (2,4-D) in plants proceeds via 3-(2,4-dichtorophenoxy) propionic acid (2,4-DP) as an intermediate. Soybean (Glycine max (L.) Merr.), kidney bean (Phaseolus vtitgaris L.), pea (Pisum. sativum L.), smooth bromegrass (Bromus inermis Leyss.), wild oat (Avena fatua L.), yellow foxtail (Setaria glauca(L.) Beauv.), barley (Hordeum vulgare L.), timothy (Phleum pratense L.). and orchardgrass (Dactylis glomerata L.) were treated with equal weights of 2,4-D and 2,4-DP. After 3 days, all plants contained DCP; however, amounts were larger in plants treated with 2.4-DP than in those treated with 2,4-D. The 2.4-DP was absorbed from the leaf surface more efficiently than 2,4-D. No evidence was found for formation of 2,4-DP from 2,4-D in any of the plant species studied. L'absence de l'acide3-(2,4 dichlorophénoxy) propionique dans les plantes traitées avec I'acide 2,4-dichlorophénoxyacétique Des experiences ont été effectuées pour rechercher si la formation de 2,4-dichlorophénoI (DCP) dans les plantes, à partir de l'acide 2.4-dichlorophénoxy acétique (2,4-D) se produit par l'intermêdiaire de l'acide 3-(2,4-dichlorophenoxy) propionique. Le soja (Glycine max(L.) Merr.). le haricot (Phaseolus vuigaris L.), Ic pois (Pisum sativum L.), le brome (Bromus inermis Leyss.), la folle avoine (Avena fatua L.), la sétaire (Setaria glauca(L.) Beauv.). I'orge (Hordeum vulgare L.), la fléole (Phleum pratense L.) et le dactyle (Dactylis ghmerata L.) ont été traités par des poids égaux de 2.4-D et de 2,4-DP. Trois jours aprés, les plantes contenaient du DCP; toutefois, les quantités trouviés furent plus importantes dans les plantes traitées avec le 2,4-DP que dans celles traitées avec le 2,4-D. Le 2,4-DP a été absorbéà partir de la surface foliaire plus efficacement que le 2,4-D. La formation du 2,4-DP à partir du 2,4-D n'a pu être prouvée dans aucune des plantes étudiécs. Die Abwesenheit von 3-(2,4′Dichlorphenaxy)-propionsäure irt mil 2,4-Dichlorphenoxytesäure behandelten Pflanzen Es wurden Versuche durchgeführt um herauszufinden. ob die Bildung von 2,4-Dichlorphenol (DCP) aus 2.4-Dichlor-phenoxyessigsäure (2,4-D) in Pflanzen über 3-(2,4-Dichlor-phenoxy)-propionsaure (2,4-DP) als Zwischcnprodukt ver-läufl. Sojabohnen (Glycine max(L.) Merr.), Gartenbohnen (Phaseolus vutgaris L.), Erbsen (Pisum sativum L.), Wehrlose Trcspe (Bromus inermis Leyss.), Flughafer (Avena fama L.), Gelbe Borsienhirse (Setaria glauca(L.) Beauv.), Gerste (Hordetim vidgarc L.), Wiesenlieschgras (Phleum pratense L.) und Knaulgras (Dactylis ghmerata L.) wurden mit gleichen Mengen an 2,4-D und 2,4-DP behandelt. Nach drei Tagen enthielten alle PHanzen DCP; aber die Menge an DCP war in den mit 2,4-DP behandelten Pflanzen grosser als in den mit 2,4-D behandelten. 2,4-DP wurde von der Blatt-oberflache besser absorbiert als 2.4-D. In keiner der untersuchten Pflanzenarten konnte ein Hinweis für die Bildung von 2,4-DP aus 2,4-D gefunden werden.  相似文献   

17.
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’.  相似文献   

18.
The residual effect of a dried methanolic extract of neem (Azadirachta indica A. Juss) seed kernels was investigated with larvae of the Egyptian cotton leafworm,Spodoptera littoralis (Boisd.), in field trials. Fodder beet was sprayed with 1% emulsions of the extract. The treated leaves were collected from the field 1, 3, 5 and 9 days after spraying and offered to the larvae for 48 h. Survival and mean weight of the larvae were recorded 2, 4, 6, 9 and 11 days from the start of exposure to the residues, and rate of pupation was calculated. The extract had a strong antifeedant effect and an intense insect growth-regulating (IGR) effect in field-treated leaves, especially with the 1- and 3-day-old residues. A positive correlation was found between the age of the residues and the mean percent of live larvae, larval weight and pupation rate of the larvae.  相似文献   

19.
Abstract

Adults and immatures of the filbert aphid, Myzocallis coryli (Goetze), a major pest of hazelnuts worldwide, were exposed to foliage treated with different concentrations of a botanical insecticide, Margosan-O, derived from extract of neem seeds. Both mature and immature stages were highly sensitive to this compound. Acute toxicity causing immediate mortality of young nymphs, particularly at higher rates (50 ppm or more), and chronic effects resulting in reduced offspring production, lengthening of nymphal development time and reduced survival of subsequent generation were recorded. The offspring production of adult aphids fed on treated leaves was reduced in a dosage-dependent manner, nearly 50% at 2.5 ppm to over 80% at 62.5 ppm. However, no nymphal survival was recorded at 25 ppm or higher doses. A repellency effect was also recorded, butthe feeding deterrence response was weak at best. Field trials also showed a marked reduction of aphid numbers on treated foliage, suggesting the effectiveness of neem against this major pest of hazelnuts.  相似文献   

20.
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.  相似文献   

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