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1.
Ageratum conyzoides L. is an annual herb in the tropics and subtropics whose extracts are known to possess pharmacological and biocidal activity.
We report on the bioactivity of a secondary metabolite (a chromene) isolated from the shoots ofA. conyzoides against some plant pathogenic fungi. Organic solvent extracts from the shoots were tested for antifungal activity against
the plant pathogenic fungiRhizoctonia solani, Sclerotium rolfsii, Botryodiplodia theobromae, Phomopsis theae andFusarium species growingin vitro on potato dextrose agar medium. The cruden-hexane extract completely inhibited the growth ofR. solani andS. rolfsii. Then-hexane extract was chromatographed over a column of silica gel followed by activity-guided fractionation to give an antifungal
principle. Structure elucidation by detailed analysis of1H,13C NMR and mass spectroscopy identified the active compound as precocene II. The growth ofR. solani andS. rolfsii was completely inhibited by precocene II at a concentration of 80–100 ppm. The sclerotia ofR. solani andS. rolfsii were also completely suppressed by 150 ppm of precocene II. Sub-culture of these inhibited fungi onto precocene II-free medium
restored growth of the fungus, indicating that precocene II is fungistatic. Crude or refined extracts fromA. conyzoides offer the possibility of biocontrol of plant pathogenic fungi.
http://www.phytoparasitica.org posting Feb. 11, 2004. 相似文献
2.
The study deals with the tachinid parasitoids ofAncyrosoma leucogrammes (Gmelin) (Heteroptera: Pentatomidae):Clytiomya dupuisi Kugler,Clytiomya sola (Rondani) andGymnosoma clavatum (Rohdendorf) (Diptera: Tachinidae). All species are recorded for the first time as parasitoids ofA. leucogrammes, andC. dupuisi was reared for the first time from a host. The parasitization rates ofC. dupuisi on adults ofA. leucogrammes varied from 7% to 9% between 1994 and 1999.C. sola andG. clavatum were reared in only small numbers.
http://www.phytoparasitica.org posting July 10, 2003. 相似文献
3.
Laboratory experiments were conducted to evaluate the prey stage preference and the daily consumption of each stage of the
coccinellid predatorStethorus punctillum Weise (Coleoptera: Coccinellidae) feeding on the two-spotted spider miteTetranychus urticae (Koch) (Acari: Tetranychidae). Groups of different life stages of the prey were offered (eggs, larvae, nymphs and adults).
The prey preference varied with the stage ofS. punctillum. First larval instars had no significant preference among theT. urticae stages offered. Second larval instars consumed significantly more spider mite larvae in comparison with nymphs. In contrast,
third larval instars indicated a strong preference for mite eggs. Significantly fewerT. urticae larvae were consumed by the fourth larval instars ofS. punctillum, in comparison with the three other mite stages. Finally, adult predators consumed significantly more mite eggs than the
other stages offered. This preferential trend was similar for all adults tested, whether during the pre-oviposition or the
oviposition period.
http://www.phytoparasitica.org posting Feb. 17, 2004. 相似文献
4.
Tachinid parasitoids ofTraumatocampa ispartaensis Doğanlar & Avcı (Lepidoptera, Thaumetopoeidae), which was found to be a new species, were collected from the cedar forests
around Isparta-Kapıdağ. The species found wereBlondelia nigripes (Fall.),Compsilura concinnata (Meig.),Pales processioneae (Ratz.),Phryxe caudata (Rond.),Exorista segregata (Rond.) andCarcelia iliaca (Ratz.). Within the six species of Tachinidae,B. nigripes was the most common one, parasitizing up to 4.6% ofT. ispartaensis pupae.
http://www.phytoparasitica.org 相似文献
5.
Adult Mediterranean fruit flies (Ceratitis capitata), collected in the field, were infected with entomophthoralean fungi. The fungi sporulated poorly on the cadavers, and resting
spores, rhizoids and cystidia were not observed. Measurements of conidia and nuclei and counts of nuclei per conidium from
different specimens suggest that the causative agents wereEntomophthora muscae sensu stricto andEntomophthora schizophorae, species recently separated from theEntomophthora muscae species complex. This is the first report ofC. capitata as a host for entomopathogenic fungi.
http://www.phytoparasitica.org posting Jan. 29, 2003. 相似文献
6.
Orobanche amethystea Thuill.,O. loricata Reichenb. andO. pubescens D’Urv. were found to parasitize the roots of cultivated plants in Israel.Orobanche pubescens is known from the local flora, and was now found to cause damage in parsley fields and toTropaeolum majus L. (nasturtium) in ornamental gardens.Orobanche amethystea andO. loricata are known as occasional weeds in Europe and were recently found for the first time in Israel.Orobanche amethystea densely populated vetch fields in Israel, andO. loricata was found in ornamental gardens. A key for the identification ofOrobanche species in cultivated areas in Israel is given, based on morphological features.
http://www.phytoparasitica.org posting Jan. 13, 2002. 相似文献
7.
Studies were carried out on the egg material ofTraumatocampa ispartaensis Doganlar & Avcı (Lep.: Notodontidae) collected onCedrus libani A. Rich. A total of 95 egg-batches were sampled over two annual generations ofTr. ispartaensis. The number of eggs in each egg-batch varied between 39 and 245 and the length of the batches varied between 7 and 36 mm.
The mean number of eggs per batch was found to be 119 and 122 in 1999 and 2000, respectively. Based on field data the oviposition
period continued from mid August to mid September. The mean hatching rate of the host was found to be 85.8% and 88.9%, whereas
the impact of egg parasitoids accounted for 11.3% and 7.4%, respectively in the 2 years.Ooencyrtus pityocampae (Mercet) was observed as the most abundant egg parasitoid, followed byOoencyrtus sp. nearmasii (Mercet) andTrichogramma brassicae Bezdenko. Based on the emergence dynamics of the egg parasitoids in the laboratory, it seems thatO. pityocampae emerged mainly in June whereasO. sp. nearmasii andT. brassicae emerged mainly in May.
http://www.phytoparasitica.org posting Feb. 3, 2003. 相似文献
8.
This work was undertaken to determine the effects ofTrichoderma spp. combined with label and sublabel rates of metam sodium on survival ofRhizoctonia solani in soil. Soils were infested with wheat bran preparations ofTrichoderma hamatum Tri-4,T. harzianum Th-58,T. virens Gl-3, andT. viride Ts-1-R3. Soil was also infested with sterile beet seeds that were colonized withR. solani. Beet seeds were later recovered, plated onto water agar plus antibiotics, and the growth ofR. solani was recorded. Preliminary experiments showed thatT. hamatum andT. virens reduced survival and saprophytic activity ofR. solani when the biocontrol fungi were incorporated into soil at 1.5% (w:w) or greater. Based on these data, biocontrol fungi in
subsequent experiments were incorporated into soil at 2%. Metam sodium at label rate killed all biocontrol fungi andR. solani. At 1:2 and 1:5 dilutions, metam sodium reduced survival ofR. solani and allTrichoderma spp. When biocontrol fungi plus the label rate of metam sodium and 1:5, 1:10, 1:50 or 1:100 dilutions of the label rate were
tested together, there were no interactions between any biocontrol agent and the fumigant with respect to colony diameter,
reflecting that allTrichoderma isolates tested reacted similarly to increasing concentrations of metam sodium. At the label rate of metam sodium, allTrichoderma spp. significantly reduced colony diameter, but not growth rate, ofR. solani from beet seed. For the levels of metam sodium tested in combination withTrichoderma, it does not appear feasible to use a reduced rate of metam sodium to controlR. solani. However, the combination ofTrichoderma with metam sodium does reduce growth ofR. solani in comparison with that provided by metam sodium at the label rate.
http://www.phytoparasitica.org posting Feb. 11, 2004. 相似文献
9.
Field studies were conducted to assess the population and the spatial dynamics of the predatory bugMacrolophus costalis Fieber (Hemiptera: Miridae) and of its prey, the aphidMyzus persicae (Sulzer) (Hemiptera: Aphidoidea), on tobacco. From an untreated tobacco field in Tithorea (central Greece), tobacco leaves
were collected from the upper and the lower half of the plants from June until September, in 1999 and 2000. The numbers ofM. costalis andM. persicae individuals per leaf were counted. Most aphids were observed during July and August (early and mid season), with densities
dropping markedly in September. In contrast,M. costalis population densities increased late in the season (September). Significantly higher numbers of aphids were found on the upper
half of the plants than on the lower half. In contrast, significantly moreM. costalis individuals were observed on the lower half. Iwao’s Regression Analysis was used in order to characterize the spatial pattern
of the two species. According to this model, in both sampling seasons, aphids andM. costalis nymphs displayed an aggregated spatial pattern, whileM. costalis adults were found to be randomly distributed among sampling units. Although moreM. costalis individuals were recorded on leaves with relatively high aphid densities, this species did not react numerically to changes
in prey density. In addition, a significant number of bugs were found on leaves with low aphid densities or no aphids at all.
http://www.phytoparasitica.org posting Dec. 18, 2002. 相似文献
10.
Pectinases extract (PE) from the fermentation product ofPenicillium oxalicum BZH-2002 was tested for its ability to induce protection against scab caused byCladosporium cucumerinum on cucumber (Cucumis sativus L.) plants. Seedlings with one true leaf were sprayed with various concentrations of PE (10–200 units ml−1) 3 days before inoculation withC. cucumerinum. Results showed that the induced local protection against the pathogen was dose-dependent when the concentrations of PE were
between 20 and 120 units ml−1; systemically induced resistance against the pathogen was not observed. Boiled PE had a slight effect on disease reduction.
Commercial pectinases prepared fromAspergillus niger showed lower protection against scab compared with PE when they were used at the same concentration of enzyme activity. No
inhibitory activity was observed on conidial germination or germ-tube growth ofC. cucumerinum. PE was further evaluated for its enhancement of defense-related enzymes. Peroxidase (PO), polyphenol oxidase (PPO) and phenylalanine
ammonia lyase (PAL) increased in cucumber seedlings after treatment with PE. PO and PPO remained at a higher level in PE-pretreated
seedlings throughout the experiment period whether pathogen-inoculated or non-inoculated, whereas PAL activity began to decrease
2 days after PE treatment.
http://www.phytoparasitica.org posting July 14, 2004. 相似文献
11.
Lian Wu Xie Shu Mei Jiang Hong Hui Zhu Wei Sun Yong Chang Ouyang Shi Kun Dai Xiang Li 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(4):571-578
Sclerotinia sclerotiorum is a worldwide ascomycete fungal plant pathogen, which causes enormous yield losses on major economic crops such as crucifers,
grain legumes and several other plant families. The objective of this research was to isolate and characterise some bioactive
products from cultures of fungi associated with the marine sponge Axinella sp. In total, nine fungal isolates were obtained from the marine sponge Axinella sp. collected from the South China Sea. A group of test strains, including two G+ strains (Bacillus subtilis and Staphylococcus aureus), two G− strains (Escherichia coli and Pseudomonas aeruginosa) and three fungi including two plant pathogenic fungi Sclerotinia sclerotiorum and Magnaporthe grisea and Saccharomyces cerevisiae, were employed as the indicator organisms for bioactivity screening. Using antagonistic tests and bioactive screening of
the ethyl acetate (EtOAc) extracts of the corresponding cultures, fungal isolate JS9 showed the stronger efficacy against
the test indicator strains, especially the indicator fungal pathogens. Isolate JS9 was further identified as Myrothecium sp. by a combination of morphological features and 18S rDNA BLAST on GenBank. Two macrocyclic trichothecenes, roridin A (compound
1) and roridin D (compound 2) were purified by tracking the activity of the EtOAc extract fractions and characterised with
spectral analyses including MS, 1H-NMR, 13C-NMR and disortionless enhancement by polarization transfer (DEPT). In vitro antifungal tests showed that the two macrocyclic trichothecenes were bioactive against S. cerevisiae, M. grisea and S. sclerotiorum with minimal inhibitory concentrations of 31.25, 125 and 31.25 μg ml−1 for roridin A, and 62.5, 250 and 31.25 μg ml−1 for roridin D, respectively. The present investigation demonstrated that two antifungal trichothecenes including roridin
A and roridin D produced by the fungus Myrothecium sp. isolated from the marine sponge Axinella sp. could be potential inhibitors against the plant pathogen S. sclerotiorum.
Lian Wu Xie and Shu Mei Jiang contributed equally to this work. 相似文献
12.
The biology ofLixus bardanae (F.) (Coleoptera: Curculionidae) on curly dock (Rumex crispus L.) in northeastern Anatolia (Bayburt, Erzurum and Kars Provinces), Turkey, was studied during the years 2000 and 2001.L. bardanae completes one generation in a year, overwintering as an adult. It feeds on leaves of the host plant. Females lay eggs individually
into stems and the young larvae create galleries in stems while feeding. Pupation occurs inside stems in cells fashioned from
frass. In late September, adults move into soil and overwinter in an upright position around the roots of the host plant.
Infestation levels were found to range between 34% and 84%. Two parasitoids,Exeristes roborator F. andEndromopoda phragmitidis Perve (Hymenoptera: Ichneumonidae), were reared fromL. bardanae.
http://www.phytoparasitica.org posting Dec. 21, 2003. 相似文献
13.
The present study was conducted to determine if there is specificity in the host-pathogen relationship between the isolates
of Xanthomonas oryzae pv. oryzae, the causal bacterium for rice blight and Leersia grasses, the alternative weed hosts of the disease. Plants of three species of Leersia, namely, L. sayanuka, L. oryzoides and L. japonica, were collected from various parts of Japan and were inoculated with the X. oryzae pv. oryzae isolates obtained from various locations in Japan and from 11 Asian countries. Four L. sayanuka plants were found susceptible to all Race II isolates and some Race I isolates, but were resistant to all Race III isolates.
Race III is known to have a wider range pathogenicity to rice cultivar groups compared with Race I and II. Although the reactions
of two L. oryzoides plants to Race I and II isolates were similar to that of L. sayanuka, the L. oryzoides plant collected from Niigata Prefecture showed a susceptible reaction to some Race III isolates. On the other hand, L. japonica plants gave reactions different those of L. sayanuka and L. oryzoides, with two plants of L. japonica found to be resistant to all test isolates collected from Japan. The Asian isolates exhibited a wide host range against the
international differential rice cultivars, but almost all of them were avirulent to Leersia plants. These results indicate that the relationship between the pathogenicity of the causal bacterium and the resistance
of host plants is very complex, and suggest that pathogenic diversity of X. oryzae pv. oryzae might be related to the resistance of Leersia spp. 相似文献
14.
Essential oils extracted fromEucalyptus blakelyi (1,8-cineole, 77.5%),Melaleuca fulgens (1,8-cineole, 56.9%) and 1,8-cineole were shown to have fumigant toxicity against different development stages ofSitophilus oryzae. The eggs ofS. oryzae were the most tolerant, followed by pupae, larvae and adults in that order.M. fulgens oil,E. blakelyi oil and 1,8-cineole at 100 μl per liter of air gave, respectively, LT50 values of 16.2, 17.4 and 9.1 h for adults, 31.1, 19.3 and 17.5 h for larvae, 55.6, 75.2 and 39.7 h for pupae, and required
>7 days for eggs. Only 1,8-cineole (200 μl
−1 air) gave a significant egg kill by 7 days and the LT95 was 134.5 h. 1,8-Cineole could be a useful new fumigant.
http://www.phytoparasitica.org posting Oct. 3, 2004. 相似文献
15.
Twenty-nine plant extracts of local species were evaluated for their potential as a source of bioactive ingredients with significant
acaricidal activity that could lead to the development of new and safe bio-acaricides. The crude extracts (70% ethanol) of
these plants were tested for their acaricidal activity against the carmine spider miteTetranychus cinnabarinus in a bioassay under controlled conditions. Mortality, repellency, and the number of eggs laid were measured. Extracts fromEucalyptus camaldulensis andInula viscosa caused more than 25% mortality. Sixteen plant extracts showed significant repellency compared with the control. The six best
extracts, resulting in more than 75% repellency, were fromAllium sativum, Capparis spinosa, Cupressus sempervirens, Lupinus pilosus, Rhus coriaria andTamarix aphylla. Extracts from 16 plants were found to cause a significant reduction in the number of eggs laid compared with the control.
The greatest reduction was achieved by extracts fromC. spinosa, Cyperus rotundus, E. camaldulensis, L. pilosus, Punica granatum, R. coriaria andT. aphylla. A relatively negative fit was found between the mean number of repelled mites and the number of eggs laid (r=−0.65), which
might indicate that most repelled mites were unable to lay eggs before leaving the leaf discs of the bioassay. Our results
show that several plant extracts have good potential for acaricidal activity and are worth further investigation.
http://www.phytoparasitica.org posting Dec. 16, 2003. 相似文献
16.
Biological effects of a commercial formulation of azadirachtin, AlignTM, were assessed onStreblote panda Hübner [1820] (Lasiocampidae) first instars by means of choice and nochoice bioassays. Survival, development, and food consumption
were recorded. The product tested did not show clear antifeedant effects, but produced dose-dependent larval mortality. All
treatments resulted in significant inhibition of growth, presumably through endocrine regulatory effects. At higher doses
assayed the product appears to have direct toxic effects. Our results suggest that AlignTM may be used in IPM programs forS. panda and should be evaluated for efficacy under field conditions.
http://www.phytoparasitica.org posting July 10, 2003. 相似文献
17.
Fourteen species in two families of the order Hymenoptera: Ichneumonidae (1 sp.) and Eulophidae (13 spp.), were recorded during
the study ofCameraria ohridella parasitoids at eight localities in Serbia. Among the observed parasitoids, the most significant species wereMinotetrastichus frontalis, Pediobius saulius, Pnigalio agraules andClosterocerus trifasciatus. In addition, at some localities the speciesMinotetrastichus platanellus andCirrospilus talitzkii were also significant. The parasitoids do not have a significant effect on the abundance ofC. ohridella because in the majority of study samples parasitism levels did not exceed 20%.
http://www.phytoparasitica.org posting Feb. 23, 2004. 相似文献
18.
Four-hundred-sixty-eightFusarium andFusarium-like isolates were obtained from crowns and subcrown internodes of winter wheat grown in Erzurum, Turkey. Of these isolates,
34.8% wereFusarium acuminatum, 32.3% wereF. equiseti, 16.9% wereF. oxysporum, 15.0% wereMicrodochium nivale (formerlyFusarium nivale), 0.6% wereF. tabacinum and 0.4% wereF. solani. In pathogenicity tests on wheat, the highest disease severity was caused by isolates ofM. nivale, whereas isolates ofF. acuminatum, F. equiseti, F. oxysporum andF. solani were slightly virulent; isolates ofF. tabacinum were nonpathogenic. This is the first report ofM. nivale andF. tabacinum from wheat in Turkey.
http://www.phytoparasitica.org posting Jan. 29, 2003. 相似文献
19.
The feeding behavior of the melon aphidAphis gossypii Glover (Homoptera: Aphididae) was monitored using the electrical penetration graph (EPG) technique on different melon (Cucumis melo L.) genotypes showing resistance to the aphid. The aphid-resistant genotypes used were PI-161375 and PI-414723, sources of
theVat andAgr genes, respectively. TGR-1551, a newC. melo accession from Zimbabwe, was also tested. Our goal was to localize the tissues where the resistance factors are expressed
and to determine if the resistance mechanisms operating in the three aphid-resistant accessions were the same. Our results
indicated that the three selected lines have resistant factors located at the epidermis, mesophyll and vascular tissues. However,
the behavior ofA. gossypii on TGR-1551 was different from the two other resistant accessions, as indicated by a longer phloem salivation phase (E1 phase).
Many of the E1 phases observed for aphids feeding on TGR-1551 were not followed by phloem ingestion (E2 phase). These results
suggest that TGR-1551 has a resistance mechanism that preventsA. gossypii from initiating ingestion from the phloem. Preference tests under free choice conditions also showed that aphids rejected
accessions TGR-1551 or PI-414723 faster than PI-161375. Our results support the hypothesis thatAgr andVat are coding for different kinds of resistance strategies. Comparisons of aphid life history parameters also indicated that
TGR-1551 is a very promising new source to breed for resistance againstA. gossypii.
http://www.phytoparasitica.org posting Jan. 16, 2002. 相似文献
20.
Populations of pear psylla,Cacopsylla pyri (L.) (Rhynchota: Psyllidae), and its natural enemies were sampled on pears in Antalya province during the years 2000–2002.
Thirty-two species of predators and three species of parasitoids were detected to be associated withC. pyri in Antalya province. The heteropterans (especially anthocorid species) were the most abundant predator group. Among the anthocorids,Anthocoris nemoralis (Fabricius) (Heteroptera: Anthocoridae), whose population was closely related to the dynamics of the pear psylla population,
was generally the principal antagonist ofC. pyri. Other species recorded during the study were the miridDeraeocoris spp., the chrysopidChrysoperla carnea L., and many coccinellid species. Although these predators are polyphagous, as are theOrius species, their populations were related to the psylla fluctuations. Among the parasitoid complex belonging to the order Hymenoptera,
the encyrtidTrechnites psyllae (Ruschka) was the only primary parasitoid. Two hyperparasites,viz., Syrphophagus mamitus (Walker) andPachyneuron aphidis (Bouché) (Encyrtidae and Pteromalidae, respectively), were detected in the surveys. Also, this study revealed new information
concerning the pear psylla parasitoid complex in Turkey. WhileT. psyllae andS. mamitus are new records to Turkish parasitoid fauna,C. pyri is a new host record forP. aphidis. The population development and abundance of pear psylla and its natural enemies, as well as the parasitization rates in
treated and untreated pear orchards, are presented here.
http://www.phytoparasitica.org posting May 6, 2004. 相似文献