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1.
The effect of rapid and gradual exposure of entomopathogenic nematodes to osmotic stresses on the induction of a dormant state
was determined with the nematodeSteinernema feltiae IS-6 infective juveniles (IJs). Rapid exposure of nematodes to glycerol at concentrations of 24% and 28% (w/w) caused the
nematodes to enter a dormant state which was characterized by shrinking and impeded motility of all nematodes within 8 h.
However, pre-exposure to gradually increasing glycerol concentrations of 5%, 10% and 18% at 4-h intervals resulted in dormancy
after 4 h exposure to 24% glycerol. The total time of exposure to glycerol solution was 16 h in gradual osmotic stress. For
nematodes exposed to 24% glycerol solution either rapidly or gradually, recovery occurred after 40 min in distilled water.
Infectivity of osmotically stressedS. feltiae IJs was evaluated by two criteria, insect mortality and invasion rate. The assays indicated that infectivity of nematodes
desiccated by rapid and gradual osmotic stresses was similar to that of fresh nematodes. Rapid exposure ofS. carpocapsae ‘All’,S. riobravis ‘Texas’,S. glaseri ‘NI’ andHeterorhabditis bacteriophora HP88 IJs to the 24% glycerol solution resulted in dormancy within 8 h. These treatments caused mortality of 48.4% and 11.7%
amongS. glaseri Nl andH. bacteriophora HP88 IJs, respectively. Similar effects were observed when these nematode species were exposed to increasing osmotic stress
of 5%, 10% and 18% at 6-h intervals. Under these same conditions, mortality ofH. bacteriophora HP88 andS. glaseri Nl IJs was 27.5% and 61.8%, respectively.
http://www.phytoparasitica.org posting Sept. 29, 2004. 相似文献
2.
Eleven soybean cultivars with different levels of susceptibility to virulent isolate SG915 ofCalonectria ilicicola were examined for reaction to metabolites produced by the isolate. When the culture filtrate from isolate SG915 was applied
to trifoliates from 11 cultivars, cvs. ‘Cajun’ and ‘Asgrow 7986’ exhibited reduced wilting severity. However, there was no
correlation between sensitivity to culture filtrate and susceptibility to the fungal isolate. Wilting severity on cv. ‘Riverside
699’ was greatest when trifoliates were treated with culture filtrates from isolates SG915 (highly virulent) and C31 (less
virulent). The dilution end-point for culture filtrates of virulent isolate SG915 was determined to be 1:8. Nonautoclaved
culture filtrates caused complete wilt of soybean trifoliates after 36 h, but autoclaved culture filtrates demonstrated a
reduced ability to wilt leaves. Electrolyte leakage from treated leaf tissues increased over time regardless of the concentrations
of culture filtrate tested. The greatest electrolyte losses were observed during the initial 30 min incubation of leaf tissues.
The highest concentration of culture filtrate (50%, v/v) induced more electrolyte loss than the low concentration (10%, v/v)
or control. These results suggest that toxic metabolites ofC. ilicicola may be involved in disease development with leaf symptom expression. 相似文献
3.
Two distinct races ofDitylenchus dipsaci in Israel were identified: one, which infects and damages onion and garlic, reproduces on pea, but does not infect phalaris
grass; and a second, which infects and damages phalaris—and, probably, also ‘Saia’ oats—but fails to infect onion and garlic.
A new ‘garlic’ race of the nematode does not appear to have been introduced into Israel together with the ‘Lavinia’ garlic
cultivar, as previously speculated, but rather the introduced Lavinia clone is highly susceptible to the existing ‘onion and
garlic’ race ofD. dipsaci. 相似文献
4.
Thirty-four isolates ofFusarium oxysporum f.sp.melonis (F.o.m.) obtained from 205 fields in melon-producing areas in the southeastern Anatolia Region of Turkey were identified on the basis
of colony morphology and pathogenicity by the root dip method. In this region the mean prevalence of wilt disease was 88.1%
and the mean incidence of disease was 47.5%. Physiologic races 0, 1, 2, and 1,2 of the pathogen were determined by their reactions
on differential melon cultivars ‘Charentais T,’ ‘Isoblon’, ‘Isovac’ and ‘Margot’ in the greenhouse. Race 1,2, representating
58.8% (20/34) of all isolates, was widely distributed. Of the other pathogenic isolates, eight were identified as race 0,
five as race 1, and one as race 2. This is the first report of physiologic races ofF.o.m. in Turkey. Of 44 melon cultivars tested in the greenhouse for resistance toF.o.m. races, 36 were found to be moderately resistant to race 0, 17 were susceptible to race 1,2, 34.1% were highly resistant to
race 1, and 52.2% had moderate resistance to race 2.
http://www.phytoparasitica.org posting July 16, 2002. 相似文献
5.
Nihal Özder 《Phytoparasitica》2002,30(4):434-436
Nymphal development time and fecundity ofSitobion avenae (F.) (Homoptera: Aphididae) were determined on nine widespread wheat varieties cultivated in Tekirdağ Region in Turkey. Tests
were carried out in controlled environment chambers (25±1°C, 65±5% r.h.; 16:8, L:D). Development time (±S.E.) ranged from
5.75±0.25 to 7.20±0.20 days. Fecundity per female ofS. avenae was found to be the highest (12.87±1.50) on wheat cv. ‘Sana’. In this investigation cvs. ‘MV-17’, ‘Miryana’, ‘Pehlivan’ and
‘Saraybosna’ were particularly resistant againstS. avenae.
http://www.phytoparasitica.org posting July 8, 2002. 相似文献
6.
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. 相似文献
7.
Feeding sites induced by the root-knot nematodeMeloidogyne artiellia in turnip (Brassica rapa), cabbage (Brassica oleracea) and barley (Hordeum vulgare) were examined by light and electron transmission microscopy, and compared with those formed byM. javanica andM. hapla. The feeding cells ofM. artiellia in turnip and cabbage showed hypertrophy, hyperplasia and vacuolization, and became multinucleate giant cells. In contrast
to the typical simple-shaped giant cells ofM. javanica andM. hapla, those ofM. artiellia had an amoeboid structure containing ‘protuberances’, which are distinct from previously reported ‘projects’ of giant cells
induced byM. incognita in other plants. Protuberances expanding between vascular cells were observed in young and developed giant cells. Since no
cell-wall fragments were found at the bases of the protuberances, either by light or electron microscopy, it is strongly indicated
that these structures were caused by local expansion of the giant cells rather than by fusion with adjacent cells. The giant
cells ofM. artiellia in barley had regular shapes of giant cells without protuberances, and resembled those induced byM. javanica orM. hapla in turnip and cabbage.
http://www.phytoparasitica.org posting Sept. 17, 2006. 相似文献
8.
The pathogenicity of steinernematid and heterorhabditid nematodes to caterpillars of the giant looper,Boarmia selenaria (Schiffermüller) (Lepidoptera: Geometridae), was determined under laboratory conditions. High mortality (over 80%) was achieved, in a petri dish bioassay, with a minimum of 20,000 infective juveniles (IJ) ofSteinernema carpocapsae (Filipjev) (=Neoaplectana carpocapsae Weiser), strain ‘All’. The LD50 was 4250 IJ per caterpillar. Similar results were obtained withS. carpocapsae, strain ‘Mexican’,Steinernema sp., strain ‘CR’;Heterorhabditis bacteriophora, strain ‘HP88’; andHeterorhabditis sp., strain ‘IS’. The first and second instars were the most susceptible stages to nematode infection. A laboratory model assay indicated that 80–90% of the caterpillars were killed when they migrated to the soil to pupate; this occurred when IJ were applied to sandy and heavy soils at a concentration of 400 IJ/cm3 soil. A greenhouse test reconfirmed the effectiveness of utilizing the entomopathogenic nematodes in an “ambush” system against caterpillars migrating to the soil. 相似文献
9.
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. 相似文献
10.
In a study of date fruit damage caused byOligonychus spp., we investigated whether the cultivar affects phenology, and on what hosts the mites over-winter. Samples were taken
from ‘Deglet Noor’, ‘Barhi’ and ‘Medjool’ trees from mid-April through mid-September during the years 1999–2002. In the ground-cover
mites were monitored by collecting Bermuda grass (Cynodon dactylon) under each sampling tree. Over 99% of the mites collected on Deglet Noor and Barhi fruit were identified asO. afrasiaticus. Mean population levels ofO. afrasiaticus reached ten mites or more (initiation of infestation) on Medjool in the second half of May, whereas on Deglet Noor this did
not occur before the first week of July. On Barhi the initiation of infestation varied between plots and years, ranging from
the second half of May to the beginning of July, but always occurred earlier than Deglet Noor. Mite populations on the pinnae
remained low from June through October, not exceeding seven mites per pinna, whereas on fruit strands they reached peak populations
of approximately 4000 mites per strand. The sex ratio (proportion of females) ofO. afrasiaticus on fruit of all three cultivars was highly female-biased, usually above 0.85. During winter,O. afrasiaticus was found on Bermuda grass in the orchard ground-cover as well as on fronds of all three cultivars.
http://www.phytoparasitica.org posting Jan. 30, 2003. 相似文献
11.
T. Musabyimana R. C. Saxena E. W. Kairu C. K. P. O. Ogol Z. R. Khan 《Phytoparasitica》2000,28(4):321-330
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. 相似文献
12.
The development time and parasitization rate ofDiaeretiella rapae (M’Intosh) onBrevicoryne brassicae (L.) feeding on differentBrassica cultivars was studied in the laboratory at 20°C. The shortest development time from egg to adult parasitoid was 11.6 days
on cabbage cv. ‘Yalova 1’ and the longest was 12.1 days on turnip cv. ‘Antep’ and rapeseed cv. local variety. Females lived
significantly longer than males on the host plants used in the study. Females and males had the shortest longevity on rapeseed
at 11.1 and 5.1 days, respectively. The highest percent parasitism ofB. brassicae byD. rapae was found on cabbage (40.20%), and the lowest was recorded on turnip (32.64%). Our results demonstrate that parasitism rate
could be influenced by the plant quality, probably due to the nutritional status of the aphids or to toxic compounds ingested
through the plant. Cabbage, cauliflower and broccoli were found to be suitable plants for the parasitoid, considering the
development time of pre-adults, and the parasitization rate ofD. rapae onB. brassicae.
http://www.phytoparasitica.org posting Jan. 23, 2007. 相似文献
13.
K. Rajappan C. Ushamalini N. Subramanian V. Narasimhan A. Abdul Kareem 《Phytoparasitica》2000,28(2):109-113
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. 相似文献
14.
Pratylenchus thornei densities were monitored in field plots of two winter wheat cultivars in a dry farming area of southern Spain. Samples were
taken fortnightly during the wheat-growing season and from the following dry fallow. Under bread wheat cv. ‘Yecora’, densities
ofP. thornei increased for 5 to 6 months and then were maintained or slightly decreased thereafter, surviving the summer dry fallow in
an anhydrobiotic state (78.2% and 85.3% survival in soil and roots, respectively). Under durum wheat cv. ‘Donpedro’, nematode
densities decreased over the growing season, although densities within the roots increased during the first 2 months of the
wheat-growing period, indicating that nematodes could penetrate the roots of this cultivar but were unable to reproduce. These
observations suggest resistance of wheat cv. Donpedro toP. thornei. 相似文献
15.
Nimet Sema Gencer Nabi Alper Kumral H. Ozkan Sivritepe Melis Seidi Hilal Susurluk Bulent Senturk 《Phytoparasitica》2009,37(3):217-224
The spider mites Tetranychus urticae Koch and Panonychus ulmi (Koch) (Tetranychidae) cause severe economic losses to vegetable farms and deciduous fruit orchards in Turkey. One of their
predators, the ladybird beetle Stethorus gilvifrons (Muls.) (Col., Coccinellidae), aggregates on mite-infested patches of plants. The present study assessed whether there is
a role for herbivore-induced plant volatiles (HIPVs) and/or odors emitted directly from these two mite species in the aggregative
response of ladybird beetles. The olfactory responses of the predator females to volatiles from T. urticae- and/or P. ulmi-infested sweet pepper (four cultivars, viz. ‘Demre’, ‘Yalova Carliston’, ‘Kandil Dolma’ and ‘Yag Biberi’), kidney bean (cv.
‘Barbunya’) and apple (M9 rootstock) were investigated using a two-choice olfactometer. Our results showed that HIPVs emitted
from both T. urticae- and P. ulmi-infested plants significantly attracted S. gilvifrons adults for all plants except the sweet pepper cv. Yag Biberi. In addition, it was found that volatiles from apple plants
infested by T. urticae and, especially, P. ulmi are more attractive for S. gilvifrons females than those emitted by other infested plants. The results also suggest that the odors of T. urticae adults and their products might influence the attraction of S. gilvifrons females. 相似文献
16.
Single-ascospore-derived isolates ofMycosphaerella fijiensis Morelet from false horn ‘Agbagba’ plantain leaves obtained from five different villages in southern Nigeria were stimulated
to mate under artificial conditions. Pairs of isolates were incubated under blacklight on potato dextrose agar (PDA) with
surface-sterilized plantain leaves or on PDA with autoclaved plantain leaves. Some isolates were observed to be sexually compatible
by their ability to produce spherical to bulb-shaped fruiting body structures (FBS) and ascospores on pairing. FBS were observed
to measure between 39–65 μm (smallest diameter) and 39–104 μm (largest diameter; mean 55.3×71.1 μm) in diameter, whereas ascospore
lengths measured between 13.0 and 14.9 μm. Length of incubation time required for FBS production was dependent on the pair
of isolates involved, the average being 40.1 days. With some pairs, ascospores were observed after 35 days of incubation.
http://www.phytoparasitica.org posting Dec. 16, 2002. 相似文献
17.
Development duration and reproduction rate of the twospotted spider miteTetranychus urticae Koch (Acarina: Tetranychidae) were studied on five different apple cultivars (‘Amasya’ (local cultivar), ‘Golden Delicious’,
‘Granny Smith’, ‘Starking Delicious’ and ‘Starkrimson Delicious’) at 25°C, 65±10% r.h. and 16:8 L:D. In addition, the same
parameters were determined on Golden Delicious leaves at three constant temperatures (20°, 30° and 35°C, 65±10% r.h. and 16:8
L:D) in the laboratory.T. urticae performed better on Granny Smith than on the other cultivars, due mainly to high daily egg production (4.6 eggs/♀/day) and
the intrinsic rate of natural increase (r
m
, which was 0.243 ♀/♀/day). The lowestr
m was observed on Amasya variety (0.231 ♀/♀/day). Development periods of immature stages ofT. urticae varied from 6.5 to 15.5 days at 35° and 20°C, respectively, for females, and from 5.9 to 14.5 days at 35° and 20°C, respectively,
for males. The development thresholds of the eggs and pre-adult stages, respectively, were 10.78° and 8.43°C, and total effective
temperatures were 57.80 and 172.41 degree-days. Mean generation time (T
o
) of the population ranged from 9.94 days at 35°C to 25.99 days at 20°C. The net reproduction rate increased from 66.99 ♀/♀
at 20°C to 92.19 ♀/♀ at 25°C, and decreased to 84.34 ♀/♀ at 30°C and to 12.04 ♀/♀ at 35°C. The highest r
m
occurred at 30°C (0.302 ♀/♀/day) and the lowest at 20°C (0.161 ♀/♀/day).
http://www.phytoparasitica.org posting Dec. 19, 2003. 相似文献
18.
R. E. Niks G. M. Butler 《European journal of plant pathology / European Foundation for Plant Pathology》1993,99(Z3):139-149
Fifteen isolates of rust fungi were collected in the United Kingdom and in the Netherlands from severalAllium species. The samples represented three putative rust species. The morphology of the telia, teliospores and urediniospores
was investigated. From urediniospores infection structures were induced on leek, and their morphology was described. Telia
and teliospores were not available on every sample. Morphology of the infection structures clearly differentiated between
‘leek’ type and ‘chive’ type isolates. The morphology of infection structures ofPuccinia mixta is very similar to that ofUromyces ambiguus, but clearly distinct fromPuccinia allii sensu Jennings from leek. Quantitative differences in urediniospore characters differentiated between the putative species,
but there was overlap between the taxa. We conclude that morphology of infection structures of urediniosporelings is a useful
trait for identification of rust isolates fromAllium. This is especially true where more than one rust species may occur on the same host species, as withAllium fistulosum. 相似文献
19.
The Hatay population of the predatory mitePhytoseiulus persimilis Athias-Henriot was released into a commercial field of cv. ‘Chandler’ strawberries for the control ofTetranychus cinnabarinus Boisduval (Acari: Phytoseiidae: Tetranychidae) in 2000 and 2001 in Silifke county of Icel on the East Mediterranean coast
of Turkey. In 2000, populations ofT. cinnabarinus were recorded in the field from the beginning of March in most plots, and increased gradually until mid-May.T. cinnabarinus populations declined to very low levels in all predator release plots approximately 2 weeks after reaching a peak. In general,
predator populations rose linearly as the population densities of spider mites increased until mid-May.P. persimilis numbers peaked during the period 16–23 May. A similar scenario developed in 2001, but because of the relatively high number
ofT. cinnabarinus in all plots at the beginning of the experiment, bothT. cinnabarinus andP. persimilis peaked almost one month earlier than in 2000. In both years, the Hatay population ofP. persimilis demonstrated good potential for the control ofT. cinnabarinus in field-grown strawberry in the Silifke region of Icel.
http://www.phytoparasitica.org posting Sept. 19, 2002. 相似文献
20.
H. A. Van Hoof H. Huttinga A. Knaap H. P. Maas Geesteranus W. H. M. Mosch D. G. J. De Raay-Wieringa 《European journal of plant pathology / European Foundation for Plant Pathology》1979,85(3):87-98
In 1975 many tumours were observed in plants ofBegonia Schwabenland grown in Aalsmeer. Submersion of the roots ofNicotiana megalosiphon seedlings in a homogenate of tumorous tissue, induced tumours after two weeks. Short periods of submergence yielded results similar to those obtained after longer periods. Tumour homogenates lost their infectivity after ten min at 50°C. Aphids transmitted the infectious agent.Treatment with propylene oxide did not inhibit infectivity completely. Filtration through a 450 nm filter removed the infectious agent.Tobacco tumor virus or a viroid could not be isolated. Cultures ofCorynebacterium fascians, isolated from tumours ofN. megalosiphon were highly infectious and induced tumours in healthyN. megalosiphon andBegonia. Tumorous tissue homogenates ofPelargonium zonale, Dahlia sp.,Gladiolus sp., andLilium sp. also caused tumours inN. megalosiphon, from whichC. fascians was isolated. It was not possible to produce tumours inN. megalosiphon with homogenates from roses with symptoms of bud proliferation.Samenvatting In 1975 werden vele tumoren waargenomen inBegonia Schwabenland op Aalsmeerse bedrijven (Fig. 1). De infectiositeit van tumorweefsel kon goed en snel worden vastgesteld door de wortels van zaailingen vanNicotiana megalosiphon in een homogenaat van tumorweefsel te dompelen. Tumoren ontstonden na twee weken, de eindbeoordeling geschiedde na een maand (Fig. 2). Ook verschillende andereNicotiana spp.,Melilotus officinalis (Fig. 3) enPisum odoratum (Fig. 4) werden aangetast.Bij de infectiositeitstoets gaven zeer korte dompeltijden even goede resultaten als langere (Tabel 1). Infectieus sap verloor zijn infectievermogen na 10 min verhitting bij 50°C. Bladluizen brachten de smetstof over. Propyleenoxide verminderde de infectiositeit wel, doch onderdrukte deze niet totaal. Bij filtratie door een 450 nm filter bleef het infectieuse agens op het filter achter. Het tumor-inducerende agens was ook aanwezig in die delen van planten met tumoren welke gezond leken en het ging voor een gering deel over met zaad (Tabel 2).Uit tumoren konden wij geen tabakstumorvirus of een viroïde isoleren. Culturen vanCorynebacterium fascians, geïsoleerd uit tumoren vanN. megalosiphon bleken zeer infectieus en veroorzaakten tumoren inN. megalosiphon enBegonia. Homogenaten van tumorweefsel vanPelargonium zonale, dahlia (Fig. 5), gladiool (Fig. 6) enLilium Mid Century Hybrid Enchantment (Fig. 7) veroorzaakten ook tumoren opN. megalosiphon, waaruitC. fascians werd geïsoleerd. Met sap van kroeskopzieke rozen konden wijN. megalosiphon niet besmetten. 相似文献