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1.
Enzyme-amplified ELISA (enzyme-linked immunosorbent assay) increased the sensitivity of detection of citrus tristeza virus and papaya ringspot virus in plant sap by 25- and 125-fold, respectively, compared with direct double antibody sandwich ELISA. The advantages of the new substrate system for the detection of low concentrations of viruses in plants are discussed.  相似文献   

2.
Data are presented on the occurrence of Braconidae (Hymenoptera parasitica) parasitizing insects associated with forest and ornamental trees and shrubs in Israel. Fifty-five genera of plants are listed, the richest in braconid fauna being tamarisk (9 species); acacia, pistachio and poplar (8 species each); carob and oak (7 species each). Of the 95 species of insect hosts mentioned, 53 are Lepidoptera, mostly Gelechiidae (7 species), Pyralidae (6 species), Noctuidae (5 species), Gracillariidae, Tortricidae, Geometridae, Lymantriidae and Lycaenidae (3 species each); 44 are Coleoptera, mostly Cerambycidae (13 species), Scolytidae (12 species), and Bostrichidae (9 species); three are Diptera. Of the 92 species of braconids listed, of which only 65 have been fully named, 56 develop in Lepidoptera, mostly Noctuidae (15 species), Gelechiidae (11 species) and Pyralidae (9 species); 33 species develop in Coleoptera, mostly Cerambycidae (12 species, Bostrichidae (10 species) and Scolytidae (5 species); and three species develop in Diptera. Thirty-eight species are new to the fauna of Israel; at least three of them are new to science,viz., Gnaptodon, Gildoria andDendrosotinus titubatus Papp.  相似文献   

3.
With the enzyme-linked immunosorbent assay (ELISA) potato virus A (PVA) could be detected reliably in potato sprouts, especially when these were young and sappy. The detection of this virus in leaves of glasshouse-grown potato plants was less reliable. The tobacco veinal necrosis strain of potato virus Y (PVYN) was readily demonstrated in foliage of glass-house-grown potato plants using an antiserum to this strain. Plants infected with the common strain (PVYO) did not react in ELISA with this antiserum. In young sappy sprouts, using the PVYN antiserum, PVYN could be detected reliably when samples with PVYO were excluded, as the reaction of samples infected with the latter virus was intermediate between PVYN-diseased and PVY-free samples. PVY was also detected in plants inadvertently infected during the experiments.  相似文献   

4.
S. Marco 《Phytoparasitica》1985,13(3-4):201-207
The detection of potato leafroll virus (PLRV) and beet western yellows virus (BWYV) and their serological relatedness were investigated by the double sandwich ELISA (DS). In both pure preparations and crude plant extracts, an unequivocal detection of each of these viruses was obtained by DS, provided the homologous antisera were used. No detection was achieved when the heterologous antisera were used, although purified virus could be detected when using the heterologous antisera for coating, providing the homologous antisera were used as conjugates. Therefore, for routine screening of BWYV or PLRV infection in plants, the DS method with homologous antisera can be used. However, it does not seem that BWYV infection in potato could be detected by the routine DS aimed for PLRV screening. In immunosorbent electron microscopy, PLRV and BWYV could be easily detected by coating grids with either homologous or heterologous antiserum. This and the possibility of trapping each virus in ELISA plates with the heterologous antiserum indicate serological cross-reactivity between PLRV and BWYV.  相似文献   

5.
Cucurbit potyviruses were collected in the field in Israel and subcultured in indicator plants in a greenhouse. Partial characterization of the Israeli cucurbit potyviruses was done on the basis of host reaction using cucurbits, peas andChenopodium spp. as hosts. Further classification of potyviruses was done by enzyme-linked immunosorbent assay (ELISA) and serological specific electron microscopy (SSEM). By these methods it was possible to identify three of the four isolates as strains of the zucchini yellow mosaic virus, while the fourth was identified as watermelon mosaic virus-2. Two of the ZYMV isolates were nonaphid-transmissible following prolonged mechanical transmission in a greenhouse. Both of these isolates were found to produce helper components capable of assisting the transmission of virions from a transmissible isolate but not those of their own.  相似文献   

6.
This contribution focuses on recent interceptions and introductions of alien scale insects and their current distribution in European and Mediterranean countries. Data and collections were gathered in markets, nurseries, and botanical gardens, mostly in Italy, either indoors or outdoors. New or recent records of the following alien species are presented: Exallomochlus hispidus (Morrison); Ferrisia virgata (Cockerell) (Pseudococcidae); Coccus viridis (Green); Milviscutulus mangiferae (Green) (Coccidae); Aonidiella orientalis (Newstead); Aspidiotus destructor Signoret; Aulacaspis tubercularis Newstead; Fiorinia fioriniae Targioni Tozzetti; Lepidosaphes pinnaeformis (Bouché); Pseudaulacaspis brimblecombei Williams (Diaspididae). New data and pest status of Phoenicococcus marlatti Cockerell (Phoenicococcidae) and Trabutina mannipara (Hemprich & Ehrenberg) (Pseudococcidae) are also reported. The possible repeated introductions of the latter from North Africa to south Italy by trans-Mediterranean winds, is hypothesized.  相似文献   

7.
Six fungicides were evaluated under laboratory and field conditions for control of Phytophthora leaf blight of taro,Coloeasia esculenta, incited byPhytophthora colocasiae. Inin vitro tests Deraosan 65W was the most effective in inhibiting the mycelial growth of the test pathogen followed by Difolatan 80W, Fytolan (copper oxychloride), Apron 35F, Topsin-M 50W and Dithane Z-78 75W. Excellent control was obtained with Demosan 65W and Difolatan 80W, good control with Apron 35F, fair control with Fytolan, and poor control with Topsin-M 50W and Dithane Z-78 75W. Results ofin vivo tests were correlated with those of thein vitro tests. Roguing of infected leaves did not eradicate the pathogen but can only delay epiphytotics.  相似文献   

8.
The reliability of biochemical diagnostic methods for avocado sunblotch viroid (ASBV) was evaluated for the Israeli avocado propagation program. Polyacry-lamide gel electrophoresis (PAGE) was compared with hybridization toin vitro 32P-labeled cDNA and ASBV-RNA probes. Although hybridization to a cDNA probe was the most sensitive method, not all known infected plants were detected. In the light of these results, the problem of diagnosing ASBV in the Israeli propagation program is discussed.  相似文献   

9.
D. Gerling 《Phytoparasitica》1984,12(2):109-118
Wild and cultivated plants in the vicinity of Kibbutz Nahshon and a few additional locations in Israel were sampled for the presence ofBemisia tabaci Genna-dius (Homoptera: Aleyrodidae). The whiteflies, together with their parasites,Eretmocerus mundus andEncarsia lutea, were found to develop on numerous host species throughout the winter. Especially high levels were reached onLan-tana camara, Abutilon grandifolium andIpomoea batatas. During late winter and spring the population on these hosts declined. From April onwards the populations increased on potatoes and sunflowers.  相似文献   

10.
Antisera were prepared against extracts of two tyrosinase-positiveStreptomyces spp., one of which caused a “deep” and the other a “russet” scab. Tyrosinase-positiveStreptomyces isolates not reacting with either of these antisera proved to be nonpathogenic to potato tubers, with few exceptions only. Not all isolates reacting with one or both antisera, however, were pathogenic and so all the serological positive ones had to be tested for pathogenicity to potato tubers. To obtain this relative specificity the antisera had to be absorbed with an extract of a non-pathogenic tyrosinase-positive isolate.  相似文献   

11.
Uredospore production per day and per sporulation period was measured under near-optimal conditions. Pustule density influenced time and rate of pustule opening, size of pustules, time of maximum sporulation, length of the sporulation period and the time and rate of tissue necrotisation. Within limits total dry weight of spores per leaf per sporulation period was independent of pustule density; it roughly equalled the dry weight of the spore producing leaf. The longest sporulation period observed was 65 days; at low pustule densities secondary pustules replaced exhausted primary pustules. Infectivity of the spores was normal up to 46 days after inoculation. The long sporulation period was epidemiologicaly interpreted as a survival mechanism.  相似文献   

12.
Lists are given of arthropod pests of avocado and pecan trees in Israel. These include ten new pests of avocado and three of pecan. The pests of economic importance on avocado includeBoarmia (Ascotis) selenaria (Schiff.) (Geometridae, Lepidoptera) andHeliothrips haemorrhoidalis (Bouché) (Thrypidae, Thysanoptera). The pests of importance on pecans includeEmpoasca decedens (Paoli) (Jassidae, Homoptera),Zeuzera pyrina L. (Cossidae, Lepidoptera), andMonellia costalis (Fitch) (Aphididae, Homoptera).  相似文献   

13.
A total of 80 single–lesion isolates of Phytophthora infestans were collected from tomatoes and potatoes in several locations in Chiang Mai and Tak provinces in 2000–2002. These isolates were analyzed for mating type, metalaxyl sensitivity, mitochondrial DNA (mtDNA) haplotype RFLP pattern as determined by probe RG57, and for microsatellite markers. All isolates were A1 mating type. Isolates from tomato were usually sensitive to metalaxyl, but isolates from potato were usually resistant to metalaxyl. With one exception, all tomato isolates were related to the US-1 clonal lineage. With two exceptions, all potato isolates were related to two European lineages. In these two provinces, the populations of P. infestans on tomatoes are clearly different from those on potatoes.  相似文献   

14.
A field survey and testing of leaf samples have given an impression of the distribution of passionfruit ringspot virus in twoAdenia and twoPassiflora spp. in Ivory Coast. The data suggest thatAdenia spp. are the original host plants of the virus. Introduction to Ivory Coast of the virus withP. edulis seems unlikely. Since theAdenia spp. prefer forest and shrub vegetations and aphid flights are shorter in the dryer savannah areas of the North, the cultivatedP. edulis has chances to remain healthy over a prolonged period of growth, which is excluded in the South of the country.  相似文献   

15.
Ethyl [2-(4-phenoxyphenoxy)ethyl] carbamate (RO 13-5223) at a dietary concentration of 100 mg kg-1 synergized the toxicity of thetrans- andcis-isomers of permethrin and cypermethrin in inhibiting the growth (measured as gain in larval weight) ofTribolium castaneum andMusca domestica vicina. With both species the synergism factor forcis-cypermethrin with 100 mg kg-1 synergist was 1.5- to twofold for RO 13-5223 and about fourfold for piperonyl butoxide. Synergism was more pronounced with first instar than with fourth instarT. castaneum larvae. Methoprene was not a pyrethroid synergist withT. castaneum larvae, so the synergistic effect of RO 13-5223 appears to depend on its structural features and not its insect-growth-regulator activity. Joint application of RO 13-5223 and pyrethroids resulted in a dual effect on bothT. castaneum andM. domestica: increased inhibition of larval growth due to pyrethroid synergism, and progeny suppression — expressed by larval and pupal mortality — due to RO 13-5223 juvenilizing activity.  相似文献   

16.
Sweet cherry is a major commercial crop in Turkey, the most important producer of the fruit worldwide. Sweet cherry decline was observed in an orchard in Ankara province of Turkey. Affected young trees exhibited reduced tree vigor, yellowing and wilting of leaves, and dieback symptoms resulted in tree death. A Phytophthora sp. was consistently isolated from necroses that appeared on taproots and crowns. The pathogen was identified as Phytophthora cryptogea based on several morphological features and DNA sequence of the internal transcribed spacer (ITS) region. P. cryptogea was pathogenic on excised shoots and 1-year-old cherry rootstocks. This is the first report of P. cryptogea causing disease of sweet cherry in Turkey.  相似文献   

17.
Almond (Prunus dulcis) is one of the well known stone fruit species grown for its unripe fruits and delicious seeds in Turkey. In the Trakya region, however, some prevailing virus infections have reduced almond yields and quality. In ten districts of Trakya, 260 leaf samples were collected from affected almond trees in June 2010. DAS–ELISA assays and RT-PCR tests were employed for the identification of viruses. As a result of these detection studies, five of the 260 leaf samples gathered from symptomatic almond trees had Plum pox virus (PPV), 81 of them had Prunus necrotic ringspot virus (PNRSV), and 11 samples contained Prune dwarf virus (PDV). Only four out of 260 samples had a mixture of these viruses. Partial nucleotide sequences of five almond isolates of PPV were determined and compared with 17 other PPV isolates in databases. Computer analysis of obtained and published nucleotide sequences showed identity ranged from 75.72% to 96.87%. Of the five PPV almond isolates obtained, however, there was a close nucleotide identity of 95.82–96.61% to Turkish isolates. Phylogenetic analysis of nucleotides and amino acids showed that five PPV isolates of almond from the Trakya Region of Turkey were clustered in the same subgroup with PPV-T Turkish isolates in GenBank. Therefore we can consider almond isolates of PPV as PPV-T strain, like the two other isolates from apricot trees in Turkey.  相似文献   

18.
Various immature stages of male and female California red scale,Aonidiella aurantii (Maskell) (Homoptera: Diaspididae), were treated with avermectin B1 (MK-936) at concentrations ranging from 10 to 100 ppm. Treatments at 10 ppm completely arrested crawler development and 20 and 100 ppm caused 100% mortality of 48-h and 7-day-old male and female 1st instar nymphs, respectively. The development of the 2nd instar was slightly affected by MK-936 at up to 40 ppm. Sublethal doses of the chemical applied to immature stages caused no dramatic reduction in the fecundity of the subsequent, mature females. MK-936 applied to male prepupal and pupal stages and mated females did not prevent male emergence, nor did it affect the ability of males to copulate and inseminate female scales, or the female fecundity. The development and adult emergence of treatedAphytis holoxanthus DeBach (Hymenoptera: Aphelinidae) larvae and pupae parasitizingChrysomphalus aonidum L. scales were not influenced by a 9 ppm MK-936 treatment; leaves sprayed with this concentration had residual toxicity onA. holoxanthus adults for only 24 h post-treatment. Feeding byChilocorus bipustulatus L. (Coleoptera: Coc-cinellidae) on 0.9 ppm MK-936-treated Florida red scales resulted in 100% mortality of 2nd instars and induced sterility in the females.  相似文献   

19.
Tagitinin A and C and hispidulin isolated fromTithonia diversifolia (Hemsl.) Gray, were potent feeding deterrents, when evaluated against 4th instar caterpillars of the Eri-silkworm(Philosamia ricini Hutt.) (Lepidoptera: Saturniidae); tagitinin F was not.  相似文献   

20.
The effect of azadirachtin and salannin, two triterpenoids isolated from seeds of neem (Azadirachta indica A. Juss), on the feeding response ofSpodoptera littoralis (Boisd.) andEarias insulana (Boisd.) larvae, was investigated. Styropor (foamed polystyrene) lamellae were painted on both sides with a mixture of 5% sucrose with different concentrations of either azadirachtin or salannin dissoled in methanol-water (3∶7). Azadirachtin strongly suppressed feeding inS. littoralis larvae even at 0.001%, whereas salannin showed some antifeedant activity at 0.005% and above. Larvae ofE. insulana were deterred from feeding on azadirachtin-treated lamellae even at 0.005%, whereas salannin was effective only at 0.01% and above. Azadirachtin applied on cotton leaves deterred larvae ofS. littoralis from feeding at all concentrations ranging between 0.001 and 0.02%.  相似文献   

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