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1.
Thomas Thomidis 《Phytoparasitica》2002,30(2):191-193
The virulence ofPhytophthora citrophthora isolated from various host-plants on three peach rootstocks (GF677, PR204, KID I) was examined. There was no significant
difference among the rootstocks with respect to their susceptibility to testedP. citrophthora isolates. The most virulent isolate originated from sycamore (Acer pseudoplatanus); isolates from pistachio trees (Pistacia vera) also showed high virulence but were significantly less virulent than the sycamore isolate. Isolates originating from plum
(Prunus domestica), almond (Prunus amygdalus) and lemon (Citrus limon) trees were moderately virulent on peach rootstocks; those from cyclamen (Cyclamen persicum) showed the lowest virulence of those tested. There was thus great variation in virulence among the testedP. citrophthora isolates. It is possible that the isolates ofP. citrophthora from sycamore, pistachio, plum, almond and lemon trees are a threat to peach trees, whereas the low virulence of the isolates
from cyclamen hosts suggests that these pathogens are not a serious threat to peach trees.
http://www.phytoparasitica.org posting Jan. 3, 2002. 相似文献
2.
The pathogenicity of Phytophthora cambivora to Mission almond seedlings was confirmed by twig inoculation in situ. An excised twig assay using four isolates of P. cambivora showed almond cvs Mission and Chellaston to be susceptible, whereas peach cv. Nemaguard, which is commonly used as a rootstock for almond, was resistant. P. cambivora isolates 179 and 108, the most and least aggressive, respectively, were selected for further studies. The excised twig assay was modified for screening micropropagated shoots in vitro for response to P. cambivora. Defoliated shoots were placed upright in agar medium colonized with the fungus, and development of necrosis was assessed over a period of 2-3 days. Shoots of Chellaston developed extensive necrosis and those of Nemaguard developed little necrosis, whereas shoots of hybrid selections from peach x almond crosses were generally intermediate in response. This method permits rapid and efficient screening of large amounts of material, and would be a useful adjunct to conventional almond breeding programmes. 相似文献
3.
Hebe Kouyeas 《EPPO Bulletin》1977,7(1):117-124
Stone fruit tree apoplexy in Greece is often caused by Phytophthora spp. Two types of Phytophthora apoplexy of stone fruit tree can be distinguished, one occurring during the hot summer period and usually caused by P. cactorum (Leb. et Cohn) Schröt. or P. citrophthora (R. et E. Smith) Leonian, and a second occurring in winter or early spring, and caused by P. syringae (Kleb.) Kleb. or sometimes P. megasperma Drechsler. Inoculation tests showed P. syringae to be highly pathogenic to apricot and almond, whereas certain clonal rootstock material showed resistance. Measures of control against Phytophthora attacks are given. 相似文献
4.
低量化学除草剂对菌株QZ-97a侵染波斯婆婆纳的影响 总被引：3，自引：0，他引：3
为探索提高真菌除草剂防效的途径,研究了胶孢炭疽菌菌株QZ-97a与低剂量化学除草剂混用的互作效果。结果表明,菌株QZ-97a孢子悬浮液与低剂量的化学除草剂氯氟吡氧乙酸(Fluroxypyr,氯氟吡氧乙酸)混用可显著提高对波斯婆婆纳的防效。1.0×10~8个孢子/ml的菌株QZ-97a孢子悬浮液与常规剂量1/10的氯氟吡氧乙酸混用可在波斯婆婆纳危害时的田间条件下经保湿24～72h后使子叶期波斯婆婆纳死亡。可见,该菌与常用的防除波斯婆婆纳的化学除草剂配合性好,具有被开发为防除波斯婆婆纳的真菌除草剂的潜力。 相似文献
5.
J. K. UYEMOTO 《EPPO Bulletin》1997,27(4):565-568
Almond scions growing on the plum rootstock Marianna 2624 (Prunus cerasifera×P. munsoniana) developed symptoms of deep pits in the xylem and necrotic bark tissues (almond brown line and decline – ABLD) or a mild etching (UME) in the woody cylinder at the union. Trees affected by ABLD decline rapidly while those affected with UME often recover and generally remain in remission thereafter. However, UME-affected trees produce significantly less trunk growth and nut yields. Symptoms of ABLD can be induced by peach yellow leafroll phytoplasma. The etiology of UME is unknown. 相似文献
6.
Phytophthora crown rot, caused primarily by Phytophthora cambivora, has caused considerable losses in almond orchards in the Willunga and northern plains areas approximately 50 km north and south of Adelaide (AU), respectively. Other Phytophthora species including P. citrophthora, P. cryptogea, P. megasperma and P. syringae have also been associated with diseased trees. Tree losses have been associated with P. cactorum isolated from trunk cankers on scaffold limbs on trees in the Riverland almond-growing area approximately 350 km north-east of Adelaide. The Al mating type of P. cambivora was the most pathogenic to almond seedlings. Cvs Mission and Chellaston, which are commonly used as rootstocks, were highly susceptible to crown rot whereas peach cv. Nemaguard was resistant. An excised twig assay has been developed to screen micropropagated shoots for resistance to P. cambivora. Metalaxyl applied at 5 g active substance per tree in spring, winter and autumn in a shallow trench close to the trunk prevented the development of trunk cankers. Foliar sprays of phosphonate (H3PO3) at 2 g active substance per litre in autumn and spring also inhibited canker development. 相似文献
7.
Ana García-Ibarra Federico Dicenta Pedro Martínez-Gómez Manuel Rubio 《European journal of plant pathology / European Foundation for Plant Pathology》2012,133(4):857-863
Apple chlorotic leaf spot virus (ACLSV) seems to be the causal agent of apricot viruela disease. This disease has become an important problem for apricot production in Spain, mainly affecting the ‘Búlida’ cultivar, although no information is available about the behaviour of other cultivars with regards to ACLSV. In this study, the behaviour of 29 apricot cultivars against ACLSV (Apr 62 isolate) was evaluated under controlled conditions in an insect-proof greenhouse. Three different rootstocks, ‘GF305’ peach, ‘Real Fino’ apricot and ‘Adesoto’ plum, were first inoculated by grafting ACLSV-infected bark and were later grafted with the apricot cultivar to be evaluated. Apricot cultivars were evaluated during three cycles of study. ACLSV was asymptomatic on the leaves of all cultivars and rootstocks, so level of susceptibility or resistance was determined by virus detection through RT-PCR. ‘GF305’ rootstock showed a greater susceptibility level than ‘Real Fino’ and ‘Adesoto’. Most of the cultivars were susceptible to ACLSV with different levels of susceptibility, and only ‘Bergeron’ and ‘Mauricio’ were resistant. 相似文献
8.
Veronica persica Poir. (Persian speedwell) is an invasive alien weed species in the upland soils throughout China. Its dominance in weed flora could be alleviated by Chorispora tenella (Pall.) (tender chorispora) in P‐poor soils and in an intense light environment. Here, three experiments in growth chambers were carried out in order to explore the effect of P and light intensity on the growth and competition of V. persica and C. tenella, the pH value in their rhizospheres, and the kinetic parameters (Km and Vmax) of the H2PO4‐ uptake by the two weed species. The ANOVA results showed that the light intensity and P level in the soil obviously influenced the growth of the two weed species. However, the effect of the P level in the soil was greater for V. persica and the effect of the light intensity was greater for C. tenella. The restriction of the growth of V. persica by a low P level in the soil was much more than that of C. tenella, but it was reversed in the two species in relation to a low light intensity. In addition, the pH was lower in the rhizosphere of C. tenella after the P‐deficient treatment and there was a lower Km in the uptake of H2PO4‐ than for V. persica, suggesting that C. tenella could adapt to a low‐P environment more easily. In conclusion, C. tenella growing together with V. persica had a competitive advantage under high‐light‐intensity and low‐P‐level conditions, but it lost its advantage with an increase in P fertilization and a decrease in light intensity. 相似文献
9.
Symptoms of shoot proliferation characteristic of phytoplasma diseases were observed on nectarine (Prunus persica var. nucipersica) and peach (P. persica) trees in the Sarada plain, south of Lebanon. The presence of phytoplasmas in the two orchards visited was confirmed by nested polymerase chain reaction using universal primers. The amplified DNA fragments were cloned and sequenced. Blast analysis of over 1000 nucleotides demonstrated the presence of ‘Candidatus Phytoplasma phoenicium’ which is considered to be the causal agent of Almond witches’ broom. This phytoplasma which belongs to the pigeon pea witches’ broom group (16SrIX) can be devastating since Almond witches’ broom has killed thousands of almond trees in Lebanon and Iran. Previous reports indicated that Almond witches’ broom may be transmitted by grafting to peach and nectarine under experimental conditions. This is the first report of a natural and epidemic spread of ‘Ca. Phytoplasma phoenicium’ in peach and nectarine. Farmers in the region were advised to eradicate the infected trees immediately. Further studies on the epidemiology of ‘Ca. Phytoplasma phoenicium’ and its vector(s) are recommended in order to develop successful eradication or disease management programmes. 相似文献
10.
Absorption of methazole by leaves of onion (Allium cepa), Stellaria media, Matricaria matricarioides and Veronica persica was rapid for the first 24 h after treatment and continued at a slower rate for up to 6 days to reach a maximum of between 35 and 60% of the amount applied. Differences in absorption between species were generally small. Absorption by the cotyledon of onion was greater than absorption into true leaves. Methazole on the leaf surface degraded to 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and small amounts of this degraded to 3-(3,4-dichlorophenyl) urea (DCPU). Methazole absorbed into leaves was relatively stable in M. matricarioides and DCPMU accumulated slowly. The rate of degradation was more rapid in the cotyledons than in the true leaves. Both in leaves and in cotyledons of onion and S. media, methazole degraded rapidly to DCPMU and this accumulated; in those of V. persica, DCPMU was degraded quickly to DCPU and unidentified products. The amount of DCPMU accumulated in the shoots was broadly correlated with the relative phytotoxicity of methazole to the different species, except for young seedlings of V. persica which contained no DCPMU but were susceptible to methazole. 相似文献
11.
The fungi causing cankers and withering of stems and branches of almond under Spanish Mediterranean conditions are: Phomopsis amygdali, Botryosphaeria berengeriana (in the form of its Dothiorella anamorph) and Valsa cincta (anamorph Cytospora cincta). P. amygdali is the most important because of its high specificity. Its development causes serious damage, particularly in orchards near the sea. B. berengeriana is a polyphagous fungus with high virulence but, because its growth depends on high temperature and adequate humidity, it is only present in orchards located in the south of the Iberian peninsula. V. cincta is widespread and causes withering of twigs. Control strategies for these three fungi with systemic fungicides have been investigated in the laboratory and glasshouse by artificial inoculations using both twig segments and seedlings of almond cv. Marcona. Benomyl, thiophanate-methyl and imazalil applied both as foliar spray and by soil drenching, have shown low fungitoxic activity in the apical part of the stems and twigs of tested plants. P. amygdali and B. berengeriana were the most affected by the three fungicides, while V. cincta was less affected. Benomyl proved to give the best control, followed at a distance by thiophanate-methyl. No control was obtained with imazalil. 相似文献
12.
为筛选高效用水核桃砧木,测定了干旱条件下7种核桃砧木幼苗的长期水分利用效率(WUEL)及其水分利用相关功能性状,分析WUEL与各功能性状的相关性,采用隶属函数法、主成分分析法和聚类分析法对7种核桃砧木幼苗的水分利用效率进行综合评价.结果表明:7种核桃砧木幼苗的WUEL存在显著的种间差异(P<0.001),其中鸡爪绵和香... 相似文献
13.
Contrasting canopy and fibrous root damage on Swingle citrumelo caused by ‘Candidatus Liberibacter asiaticus’ and Phytophthora nicotianae 
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下载免费PDF全文 Huanglongbing (HLB), associated with the phloem‐limited bacterium ‘Candidatus Liberibacter asiaticus’ (Las), is devastating trees in citrus orchards of Florida. Additionally, Phytophthora nicotianae, omnipresent in citrus soils, causes root rot that reduces water and nutrient uptake by fibrous roots. To investigate fibrous root damage and replacement and canopy size in relation to infection of fibrous roots by Las and P. nicotianae, rootstock seedlings of Swingle citrumelo (Citrus paradisi × Poncirus trifoliata) were inoculated with Las or P. nicotianae in two greenhouse pot trials. Phytophthora nicotianae caused root damage within 5 weeks post‐inoculation, which led to greater reduction of canopy size than for Las‐infected seedlings by the end of the experiment. Las increased accumulation of fibrous root biomass at 5 weeks post‐root trimming (wpt) in the 2014 trial and at 11 wpt in the 2015 trial. New root length was not consistently increased by Las. Reduced total leaf area of symptomless Las‐infected seedlings compared to noninoculated controls might be due to the combined effect of altered carbohydrate allocation between shoots and roots and altered leaf morphology. 相似文献
14.
More than 600 Prunus samples were examined by using a nonradioactive digoxigenin-labelled RNA probe specific for hop stunt viroid (HSVd). Prunus salicina and Prunus armeniaca appeared to be better hosts than Prunus persica . The weak viroid concentration in flowers and young leaves of peach trees growing in the field did not permit its detection in such samples. The diagnosis was more reliable (about 85%) with bark and leaves aged 4 months and more, from regrowths of GF 305 peach seedlings inoculated and kept in the greenhouse. Detection of HSVd in leaves and bark of apricot and Japanese plum plants aged 3 months or more also proved reliable (about 80% and 90%, respectively). HSVd could be transmitted in apricot, peach and plum nucleic acid preparations to GF 305 peach seedlings by repeated stem slashing, and to cherries ( Prunus avium and Prunus serrulata ) by approach grafting with an infected P. salicina source. The viroid was eliminated from 18% of the clones obtained after thermotherapy.
In the course of this study, 25 selected Prunus accessions suspected to be infected by unusual diseases were analysed by hybridization with a HSVd-specific probe and by indexing on GF 305 peach seedlings in the greenhouse. Fifteen of these accessions were found to be infected by HSVd, 19 induced reddish marbling, and four induced small blackish spots on the leaves aged about 4 months. Repeated assays showed that these foliar symptoms were not caused by the viroid. Peach red marbling (PRMa) has not been associated with any known virus and seems to be caused by an infectious agent not yet described. That could also be the case with the agent of peach sooty ringspot (PSRS). PRMa and PSRS symptoms were reproduced by grafting and indexing, and their causal agents eliminated by thermotherapy in a significant fraction of the treated plants. They behave like viral agents and can infect the different Prunus species studied. 相似文献
In the course of this study, 25 selected Prunus accessions suspected to be infected by unusual diseases were analysed by hybridization with a HSVd-specific probe and by indexing on GF 305 peach seedlings in the greenhouse. Fifteen of these accessions were found to be infected by HSVd, 19 induced reddish marbling, and four induced small blackish spots on the leaves aged about 4 months. Repeated assays showed that these foliar symptoms were not caused by the viroid. Peach red marbling (PRMa) has not been associated with any known virus and seems to be caused by an infectious agent not yet described. That could also be the case with the agent of peach sooty ringspot (PSRS). PRMa and PSRS symptoms were reproduced by grafting and indexing, and their causal agents eliminated by thermotherapy in a significant fraction of the treated plants. They behave like viral agents and can infect the different Prunus species studied. 相似文献
15.
Erich Seemüller Eckard Moll Bernd Schneider 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(2):109-119
In three trials carried out over a period of 24 years, open-pollinated seedlings of Malus sieboldii and M. sargentii and 22 apomictic rootstock selections with either M. sieboldii, M. sargentii or M. hupehensis in their parentage were examined for apple proliferation (AP) resistance in comparison to clonal M. x domestica-based rootstocks M 9, M 11, M 13, stocks of the B (Budagovski) and the Polish P series and M. robusta seedlings. Following experimental inoculation or natural infection the Golden Delicious-grafted trees on most of the M. sieboldii-derived progenies showed a high level of AP resistance expressed by low cumulative disease indices, a high percentage of
non or little affected trees, low incidence of the small fruit symptom and non or little effect on vigour. Trees on M 9 and
M 11, B 118 and M. robusta seedlings were moderately susceptible while trees on progenies with M. sargentii and M. hupehensis parentage, rootstocks of the P series, B 9, B 490 and M 13 proved highly susceptible. The screening also showed that rootstocks
with M. sieboldii and M. sargentii parentage are often highly susceptible to latent apple viruses. Trees on most of the M. sieboldii-based progenies were more vigorous than trees on standard stock M 9, whereas the vigour of some progenies from selections
with M. sargentii parentage was in the range of M 9 or even lower. Productivity was often correlated with the vigour. 相似文献
16.
E. K. Dann A. W. Cooke L. I. Forsberg K. G. Pegg Y.‐P. Tan R. G. Shivas 《Plant pathology》2012,61(5):896-902
Calonectria ilicicola, Gliocladiopsis sp. and Ilyonectria liriodendri were isolated from diseased roots of young avocado trees. Pathogenicity studies with seedlings of three avocado cultivars, Velvick, Hass and Reed, demonstrated that Calonectria ilicicola is a severe root rot pathogen, reducing the biomass of healthy roots, and reducing plant height over time. Calonectria ilicicola was re‐isolated from diseased roots. Ilyonectria liriodendri and Gliocladiopsis sp. were not pathogenic and plant height was increased after Gliocladiopsis sp. amendment compared to all other treatments in trials with cvs Velvick and Hass. 相似文献
17.
Viruses and viroids of stone fruits in Syria 总被引：1，自引：0，他引：1
F. Ismaeil A. Myrta N. Abou Ghanem-Sabanadzovic S. Al Chaabi V. Savino 《EPPO Bulletin》2002,32(3):485-488
Field surveys were carried out in the main stone fruit-growing areas of Syria to evaluate the sanitary status of mother blocks, varietal collections and commercial orchards. The presence of virus and virus-like diseases was checked by enzyme-linked immunosorbent assay (ELISA), sap transmission to herbaceous hosts, testing on the woody indicators Prunus persica cv. GF 305 and Prunus serrulata cv. Kwanzan and dot-blot hybridization tests. A total of 1337 samples was tested by ELISA (444 apricot, 283 peach, 246 cherry, 222 almond and 142 plum). The overall mean infection rate was 13%, and the percentage infection level of single species was: peach 24%, cherry 16%, almond 13.5%, apricot 6%, plum 5%. The following viruses and viroids were detected: PNRSV, PDV, ACLSV, PPV, ApMV, PLMVd and HSVd 1 . 相似文献
18.
Potato mop-top furovirus (PMTV) was isolated for the first time in Sweden in 1985. During 1986 and 1987, soil samples from potato fields, mainly in the south-west of Sweden, were tested for PMTV. The virus was detected in 49 out of 305 samples tested. PMTV was also found to be present in soil collected from potato riddles during potato grading in early spring. The soil samples were tested by using Nicotiana clevelandii and N. debneyi as bait plants in a glasshouse. Seven potato cultivars were grown in a PMTV-infested field. PMTV symptoms in the tubers, i.e. external and/or internal brown rings and arcs (spraing), were observed in cvs Evergood, Provita, Saturna and Ukama but not in cvs Bellona, Bintje or King Edward. Very few, or no, PMTV symptoms were found in tubers of susceptible cultivars when examined 2-3 weeks after lifting. In later examinations spraing appeared and increased. The increase was greater in tubers stored at 9°C than in those at 4°C, and in cut than in uncut tubers. 相似文献
19.
20.
After cultivation in early April of a sandy loam soil with 9500 apparently viable seeds/m2 in 0–10 cm, 295 seedlings/m2 emerged of which about half survived to maturity in July. Seeds were dispersed from mid-June to November and 136,460/m2 were returned to the soil, representing a 14-fold increase in the seed bank. Application of soil-acting herbicides reduced the numbers of weeds and the total seed output, but that of tolerant species was increased. Maximum numbers of seeds were 59,980/m2 for Chenopodium album, 39,430/m2 for Sleltaria media and 37,580/m2 for Veronica persica. 相似文献