首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 406 毫秒
1.
During a survey carried out in August 2013 along all coastal areas of north-eastern Tunisia (governorships of Bizerte, Ariana, Tunis, Ben Arous, Nabeul, Sousse), eucalyptus trees were found to be highly infested by the invasive pest Glycaspis brimblecombei Moore, 1964, also known as red gum lerp psyllid. This insect, native to the Australian region and secondarily dispersed also in the Americas, Mauritius, Madagascar and South Africa, very recently started to invade the Mediterranean region and in almost 5 years has spread to the Iberian Peninsula, Italy, Greece and Morocco. Its presence in Tunisia (which is recorded here for the first time) most probably dates back to summer 2012, since typical necrotic spots caused by the lerp of the psyllid had already been noted on leaves during spring 2013. No presence of its main parasitoid – Psyllaephagus bliteus Riek – nor of any other natural enemy, was noted up to now during our survey in Tunisia.  相似文献   

2.
Fifty-four insect and four mite species are included in a list of the entomofauna of plane trees in Israel. Only two species are monophagous:Phyllonorycter platani (Stgr.) (Lepidoptera: Gracillariidae) andEdwardsiana iranicola Zachv. (Heteroptera: Cicadellidae). Four species are noxious:P. platani, the main insect pest of the plane trees in Israel;Zeuzera pyrina L. (Lepidoptera: Cossidae);Kalotermes flavicollis F. (Isoptera: Kalotermitidae); andE. iranicola. Of much lesser importance areTargionia vitis Sign. (Homoptera: Diaspididae),Heliothrips haemorrhoidalis Bché. andRetithrips syriacus May. (Thysanoptera: Thripidae). About half of the listed species are natural enemies and many are parasites ofP. platani. Details are given on the noxious species, together with recommendations for prevention and control.  相似文献   

3.
Stemphylium lycopersici (Enjoji) W. Yamam was initially described from tomato and has been reported to infect different hosts worldwide. Sequence analyses of the internal transcribed spacer (ITS) regions 1 and 2, including 5.8S rDNA (ITS-5.8S rDNA) and glyceraldehyde-3-phosphate dehydrogenase (gpd) gene, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), as well as virulence studies were conducted to analyze 46?S. lycopersici isolates. Stemphylium lycopersici isolates used in this study were obtained from diseased tomato (Solanum lycopersicum L.), eggplant (Solanum melongena L.), pepper (Capsicum annuum L.) and lettuce (Lactuca sativa L.) from major vegetable growing regions of Malaysia, including the three states of Pahang, Johor and Selangor between 2011 and 2012. Phylogenetic analysis of a combined dataset of the ITS-5.8S rDNA and gpd regions indicated that all isolates were clustered in the sub-cluster that comprised S. lycopersici, and were distinguished from other Stemphylium species. Cluster analyses using the UPGMA method for both RAPD and ISSR markers grouped S. lycopersici isolates into three main clusters with similarity index values of 67 and 68 %. The genetic diversity data confirmed that isolates of S. lycopersici are in concordance to host plants, and not geographical origin of the isolates. All S. lycopersici isolates were pathogenic on their original host plants and showed leaf spot symptoms; however, virulence variability was observed among the isolates. In cross-inoculation assays, the representative isolates were able to cause leaf spot symptoms on eggplant, pepper, lettuce and tomato, but not on cabbage.  相似文献   

4.
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   

5.
Anthracnose, caused by Colletotrichum capsici, is a major disease of chilli (Capsicum annuum L.) affecting both fruit and seed quality. The pathogen is both internally and externally seedborne. However, a rapid and sensitive method for detection of this pathogen in seeds is currently limited. In this study, a polymerase chain reaction (PCR) method based on sequence characterized amplified region (SCAR) marker was developed for specific and sensitive detection of C. capsici in chilli seeds and fruits. The developed SCAR primers were highly specific to C. capsici and resulted in the amplification of an expected 250-bp fragment from genomic DNA of all seven of the C. capsici isolates tested. No amplification occurred when the SCAR primers were tested with genomic DNA from three other fungal isolates and four other Colletotrichum species. The SCAR primers successfully amplified similar sized fragments from DNA derived from C. capsici-infected chilli fruits. The molecular detection sensitivity of C. capsici was 1 pg of purified C. capsici DNA template and 25 ng of DNA from C. capsici-infected chilli fruits. A real-time PCR assay was also developed using SYBR Green chemistry for detection of C. capsici in chilli fruits and seeds. The standard curve obtained showed a linear correlation between copy number of the cloned target DNA sequence of C. capsici and cycle threshold (Ct) values, with R2 of 0.98. These PCR-based assays may be highly useful in detection of this important pathogen in chilli seeds and fruits in plant quarantine laboratories.  相似文献   

6.
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   

7.
The protection of plants against bacterial disease is one of the important issues that need to be studied in agricultural applications. The application of a transgene, such as a gene that encodes plant ferredoxin-like protein (PFLP), to generate resistant plants is one possible strategy. Our previous reports have demonstrated that transgenic plants that express extracellular PFLP (ESF plants) are more resistant to bacterial pathogens. This protein intensifies the hypersensitive response (HR) in plants when they are infiltrated by a pathogen-associated molecular pattern (PAMP), harpin (HrpZ), from Pseudomonas syringae. In addition, this intensified HR is associated with the expression of membrane-bound NADPH oxidase. Thus, we attempted to determine the involvement of PFLP in intensifying PAMP-triggered immunity (PTI) to enhance disease resistance. First, we showed that transgenic Arabidopsis plants with the pflp gene were resistant to bacterial soft rot caused by Pectobacterium carotovorum subsp. carotovorum (Pcc). Then, the fliC gene which encoded flagellin from Pcc was cloned and expressed. The FliC protein was used in the functional study with PFLP in Arabidopsis Col-0 plants. The reactive oxygen species (ROS) generation and HR ratio were induced by the treatment with both PFLP and FliC together, but they were not induced by treatment with PFLP or FliC alone. Similar results were confirmed in ESF plants, where FliC elicited rapid ROS accumulation and callose deposition. Moreover, we demonstrated that the PFLP-intensified ROS generation and HR were related to Ca2+ influx and activation of NADPH oxidase. We concluded that the PFLP-intensified disease resistance is associated with the intensification of PAMP-triggered immunity.  相似文献   

8.
The occurrence and geographic distribution of longidorid nematode species inhabiting the rhizosphere of cultivated and wild olive and grapevine in Crete Island were investigated. Morphological and morphometrical studies identified five Longidorus and six Xiphinema species, with frequencies of prevalence (for wild and cultivated olives and grapevines, respectively) as follows: Longidorus closelongatus (2.0–13.3 %), L. cretensis (1.0–6.7 %), L. moesicus (13.3 % only in grapevines), L. orientalis (3.3 % only in grapevines), L. pseudoelongatus (7.0 % only in olives), Xiphinema cretense n. sp. (3.0 % only in olives), X. index (3.0–23.3 %), X. israeliae (6.3 % only in olives), X. italiae (3.3–10.0 %), X. pachtaicum (26.7–42 %) and X. simile (3.3 % only in grapevines). Xiphinema cretense n. sp. is characterized by a body size 3,872–6,135 μm long, lip region anteriorly rounded, separated from the rest of the body by a depression, odontostyle and odontophore 140.6 and 80.3 μm long respectively, vulva position at 46.0–50.5 %, female tail 31.0–38.0 μm long, nearly hemispherical with curvature essentially dorsal and with a tip completely rounded or presenting a very short bulge, c ratio (119.1–186.9), c’ ratio (0.7–0.8). Molecular characterisation using D2-D3 expansion regions of 28S rRNA, 18S rRNA and ITS1-rRNA was carried out and maximum likelihood and Bayesian inference analysis were used to reconstruct phylogenetic relationships among these species and with other longidorids.  相似文献   

9.
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   

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.
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   

12.
Tomato yellow leaf curl virus (TYLCV) causes huge losses to tomato production worldwide. In July 2011 and July–August 2012, we screened for potential TYLCV hosts in a tomato-growing area in Shandong Province, the core vegetable-producing region in China. PCR detection showed that 5 species of plants, Zinnia elegans, Acalypha australis, Gossypium hirsutum, Abutilon theophrasti, and Nicotiana tabacum, were infected. Full genomic sequences of the new TYLCV isolates were obtained and submitted for sequence analysis. Sequence alignment and similarity analysis showed that they all belonged to the TYLCV-IL strain.  相似文献   

13.
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   

14.
  相似文献   

15.
The F2 population derived from a cross between isolates pRx (Avr1c-Avr1c) and ps1 (avr1c-avr1c) of Phytophthora sojae, fungal agent of soybean stem and root rot, was used to determine the genetic basis of avirulence towards Rps1c gene in soybean. The results indicated that this avirulence is dominant and controlled by a single locus, as expected for a simple gene-for-gene model. Segregation of Avr1c in the F2 progeny of this cross fits a 3:1 ratio. Four of 80 AFLP primers effectively distinguished the avirulent pRx from the virulent ps1. Among the 5 specific markers, band C was amplified from the avirulent pRx by primer set EGC/MAT, then recovered and cloned. This AFLP marker was successfully transfered to a SCAR marker through sequencing, primer design and specific amplication of the DNA of the avirulent pRx. Results of validity and specificity experiments with 50 individuals of the F2 progeny and 50 field isolates demonstrated that this SCAR marker (a 616-bp fragment) can be successfully and specifically amplified from the P. sojae isolates that have Avr1c gene.  相似文献   

16.
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   

17.
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   

18.
This study aimed to develop a polyprobe for the simultaneous detection of four viroids that infect grapevine: Hop stunt viroid (HSVd), Australian grapevine viroid (AGVd), Grapevine yellow speckle viroid-1 and 2 (GYSVd-1, 2), using a non-isotopic dot blot hybridization technique. A polyprobe was constructed by cloning tandem full-length sequences of HSVd, AGVd and GYSVd-1 into a single vector. The cRNA polyprobe detected all four viroids with similar sensitivity to that obtained using individual probes. In addition, samples of 78 varieties from Beijing and Xinjiang were analyzed using the polyprobe to survey the incidence of grapevine viroids in China. The result demonstrated that grapevine viroids were detected in 56 (71.8%) varieties. In this study, a rapid, reliable and cost-effective approach to the simultaneous detection of four grapevine viroids has been developed which has the potential for routine use in quarantine and certification programs.  相似文献   

19.
Research work was carried out to identify and ascertain the species status of the mango biotype of Colletotrichum gloeosporioides infecting mangoes in Ghana. Forty five isolates of Colletotrichum species were collected from 12 districts in Ghana while five each were obtained from mango fruits from Florida, Mexico and Puerto Rico. The entire internal transcribed spacer region, partial beta-tubulin gene and partial glyceraldehyde-3-phosphate dehydrogenase gene of isolates were sequenced and used in phylogenetic studies. The results of the sequence analysis of the first ribosomal transcribed spacer (ITS 1) region showed that 35 % of the isolates from Ghana and all the five isolates from Mexico were the mango biotype of C. gloeosporioides, while the others were not. Phylogenetic studies showed that the mango biotype of the pathogen was Colletotrichum asianum but not C. gloeosporioides as previously thought. However, the other isolates that were not the mango biotype were identified as Colletotrichum siamense and Colletotrichum species which had probably cross-infected mango from other fruit crops in the field.  相似文献   

20.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号