scholarly journals Diagnostic Procedures to Detect Xylella fastidiosa in Nursery Stocks and Consignments of Plants for Planting

Agriculture ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 922
Author(s):  
Giuliana Loconsole ◽  
Stefania Zicca ◽  
Lorenzo Manco ◽  
Oumaima El Hatib ◽  
Giuseppe Altamura ◽  
...  
Keyword(s):  
Prunus Avium ◽  
Xylella Fastidiosa ◽  
Diagnostic Procedures ◽  
International Standards ◽  
Nerium Oleander ◽  
Test Plant ◽  
Plant Materials ◽  
Potted Plants ◽  
Molecular Tests ◽  
Lavandula Stoechas

Preventive measures for infectious diseases caused by the harmful plant pathogenic bacterium Xylella fastidiosa include inspections and diagnostic tests on imported consignments of plants and in nurseries. Currently, mandatory checks on plant propagating materials are enforced in Europe (EU regulation 2021/1201) for the most susceptible species found in the European outbreaks, and prior to move propagating materials of the “specified plants” from nurseries located in the so-called “demarcated areas”. These requirements imply sampling and laboratory manipulation of a large number of samples, nevertheless plants to be sampled are often small size potted plants. While statistically based methods for inspections and sampling are available, namely the International Standards for Phytosanitary Measures n. 31, validated laboratory procedures to test large volumes of plant materials are lacking. In this work, we optimized two distinct protocols to detect X. fastidiosa in pooled plant materials collected from lots of plants for planting. The first protocol was designed to test in pool few samples (up to 8), the second to process through a single diagnostic test plant material from a high number of samples (up to 225). Accuracy of the newly developed protocols was assessed by pooling at different ratio tissues collected from healthy and infected Polygala myrtifolia, Nerium oleander, Olea europaea, Lavandula stoechas and Prunus avium. Moreover, tests included pools of plantlets of Brassicaceae and Solanaceae artificially inoculated with stem portions of infected periwinkle. Using both protocols, high diagnostic sensitivity values were generated using serological and molecular tests, with qPCR consistently yielding the highest performance values, regardless the host species tested.

Evaluation of Lavandula stoechas L. subsp. stoechas L., Mentha spicata L. subsp. spicata L. essential oils and their main components against sinusitis pathogens

2018 ◽  
Vol 73 (9-10) ◽  
pp. 353-360 ◽  
Author(s):  
Nursenem Karaca ◽  
Betül Demirci ◽  
Fatih Demirci
Keyword(s):  
Gas Chromatography ◽  
Essential Oils ◽  
Folk Medicine ◽  
Gas Chromatography Mass Spectrometry ◽  
Mentha Spicata ◽  
Plant Materials ◽  
Lavandula Stoechas ◽  
Main Components

Abstract Lavandula stoechas subsp. stoechas and Mentha spicata subsp. spicata are used for the treatment of sinusitis in Turkish folk medicine. The components of essential oils obtained by hydrodistillation were determined by gas chromatography-flame ionization detector (GC-FID), gas chromatography/mass spectrometry (GC/MS), and thin layer chromatography (TLC). Major components of L. stoechas and M. spicata oils were determined as camphor (46.7%) and carvone (60.6%), respectively. The antibacterial activity of essential oils and their main components were tested against the common selected sinusitis pathogens Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, and Pseudomonas aeruginosa using in vitro agar diffusion, microdilution, and vapor diffusion methods. As a result, the tested plant materials, which are locally and natively used against sinusitis, were relatively mild antibacterial (in vitro MICs 310–1250 μg/mL) in action. To use essential oils and their components safely in sinusitis therapy, further detailed in vivo experiments are needed to support their efficacy.

scholarly journals First Report of Oleander Leaf Scorch Caused by Xylella fastidiosa in Florida

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 198-198 ◽  
Author(s):  
R. L. Wichman ◽  
D. L. Hopkins ◽  
T. A. Wichman
Keyword(s):  
Xylella Fastidiosa ◽  
Trisodium Citrate ◽  
Nerium Oleander ◽  
Sodium Ascorbate ◽  
Eastern United States ◽  
Pcr Assay ◽  
First Report ◽  
Leaf Scorch ◽  
Chlorotic Mottling ◽  
Specific Amplification

During the spring of 1998, mature oleanders (Nerium oleander L.), pruned to form a 2-m-high hedge along an interstate highway in Orlando, FL, were observed declining and dying. Numerous plants along a 200-m section of highway were in various stages of decline. Symptoms began as chlorotic mottling along the edges of leaves and as the disease progressed, mottling became more severe and leaf margins became necrotic. Scorched leaves died, and symptoms spread throughout the plants, resulting in defoliation. New growth from the base of affected plants was stunted and severely mottled. Petioles and leaf midribs were taken from leaves with mottling symptoms and assayed for the presence of Xylella fastidiosa by polymerase chain reaction (PCR) and culturing on periwinkle wilt agar medium. For PCR assay, infected tissue from three plants was extracted by grinding in SCP buffer (1.0 g of trisodium citrate and 1.0 g of disodium succinate per liter, in 0.015 M phosphate buffer, pH 7.0) containing 0.02 M sodium ascorbate and 5% acid-washed polyvinylpyrrolidone. Amplification was performed with primers RST31 and RST33, as previously described, for specific detection of X. fastidiosa strains (1). A X. fastidiosa-specific amplification product was produced from all three extracts. For culturing, petioles and leaf midribs were cut into 0.5-cm sections, and sap was extracted from the tissue by squeezing with a forceps. Sap was blotted directly onto the medium and incubated at 28°C. Colonies typical of X. fastidiosa were observed after 10 to 14 days of incubation, and single colonies were transferred to fresh periwinkle wilt agar. The colonies were confirmed as X. fastidiosa by PCR assay. Two of the oleander strains were used to inoculate three red and three white 18-month-old oleanders by needle-puncture of the stem through a cloudy drop of bacterium in SCP buffer (108 CFU/ml). For controls, three red and three white oleanders were inoculated with SCP buffer alone. After 9 weeks in a screenhouse, marginal leaf mottling was observed in both the red and white oleanders inoculated with X. fastidiosa, and the bacterium was reisolated from leaves as described above, completing Koch's postulates. Control plants remained symptomless. Oleander leaf scorch caused by X. fastidiosa has been described previously in California and Texas (2). This is the first report of oleander leaf scorch in Florida and the eastern United States. References: (1) G. V. Minsavage et al. Phytopathology 84:456, 1994. (2) A. H. Purcell et al. Phytopathology 89:53, 1999.

scholarly journals Causal Role of Xylella fastidiosa in Oleander Leaf Scorch Disease

1999 ◽  
Vol 89 (1) ◽  
pp. 53-58 ◽  
Author(s):  
A. H. Purcell ◽  
S. R. Saunders ◽  
M. Hendson ◽  
M. E. Grebus ◽  
M. J. Henry
Keyword(s):  
Prunus Persica ◽  
Xylella Fastidiosa ◽  
Xylem Sap ◽  
Nerium Oleander ◽  
Madagascar Periwinkle ◽  
Leaf Scorch ◽  
Valley Oak ◽  
Sap Feeding ◽  
Negative Controls

A lethal leaf scorch disease of oleander (Nerium oleander) appeared in southern California in 1993. A bacterium, Xylella fastidiosa, was detected by culturing, enzyme-linked immunoassay, and polymerase chain reaction in most symptomatic plants but not in symptomless plants or negative controls. Inoculating oleanders mechanically with X. fastidiosa cultures from diseased oleanders caused oleander leaf scorch (OLS) disease. The bacterium was reisolated from inoculated plants that became diseased. Three species of xylem sap-feeding leafhoppers transmitted the bacterium from oleander to oleander. The bacterium multiplied, moved systemically, and caused wilting in Madagascar periwinkle (Catharanthus rosea) and leaf scorch in periwinkle (Vinca major) in a greenhouse after inoculation with needle puncture. No bacterium was reisolated from grapevine (Vitis vinifera), peach (Prunus persica), olive (Olea europaea), California blackberry (Rubus ursinus), or valley oak (Quercus lobata) mechanically inoculated with OLS strains of X. fastidiosa. A 500-bp sequence of the 16S-23S ribosomal intergenic region of oleander strains showed 99.2% identity with Pierce's disease strains, 98.4% identity with oak leaf scorch strains, and 98.6% identity with phony peach, plum leaf scald, and almond leaf scorch strains.

scholarly journals Diagnostic and prognostic potential of the proteomic profiling of serum-derived extracellular vesicles in prostate cancer

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Michele Signore ◽  
Romina Alfonsi ◽  
Giulia Federici ◽  
Simona Nanni ◽  
Antonio Addario ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Extracellular Vesicles ◽  
Biological Fluids ◽  
Prognostic Significance ◽  
Diagnostic Procedures ◽  
Protein Microarrays ◽  
Specific Protein ◽  
Clinical Settings ◽  
Proteomic Profiling ◽  
Molecular Tests

AbstractExtracellular vesicles (EVs) and their cargo represent an intriguing source of cancer biomarkers for developing robust and sensitive molecular tests by liquid biopsy. Prostate cancer (PCa) is still one of the most frequent and deadly tumor in men and analysis of EVs from biological fluids of PCa patients has proven the feasibility and the unprecedented potential of such an approach. Here, we exploited an antibody-based proteomic technology, i.e. the Reverse-Phase Protein microArrays (RPPA), to measure key antigens and activated signaling in EVs isolated from sera of PCa patients. Notably, we found tumor-specific protein profiles associated with clinical settings as well as candidate markers for EV-based tumor diagnosis. Among others, PD-L1, ERG, Integrin-β5, Survivin, TGF-β, phosphorylated-TSC2 as well as partners of the MAP-kinase and mTOR pathways emerged as differentially expressed endpoints in tumor-derived EVs. In addition, the retrospective analysis of EVs from a 15-year follow-up cohort generated a protein signature with prognostic significance. Our results confirm that serum-derived EV cargo may be exploited to improve the current diagnostic procedures while providing potential prognostic and predictive information. The approach proposed here has been already applied to tumor entities other than PCa, thus proving its value in translational medicine and paving the way to innovative, clinically meaningful tools.

scholarly journals Evaluation of the bacteria formulation different inoculum densities on growth and development of Euphorbia pulcherrima

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Fazilet Parlakova Karagöz
Keyword(s):  
Enzyme Activity ◽  
Nitrate Reductase ◽  
Maximum Level ◽  
Stem Length ◽  
Euphorbia Pulcherrima ◽  
Plant Materials ◽  
Potted Plants ◽  
Crown Width ◽  
Flower Stem

AbstractThis research was carried out to examine the effects of different doses of bacterial formulation comprised of a mixture of Bacillus megaterium TV-91C, Pantoea agglomerans RK-92 and Kluyvera cryocrescens TV-113C strains on the plant development and bract quality of poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch), which are one of the most important potted plants grown for their fleshy bracts of the horticultural sector. The study was carried out in a climate-controlled research greenhouse from 8 August 2018 to 15 January 2019 in Erzurum (Turkey). Rooted cuttings of poinsettia [E. pulcherrima Willd. ex Klotzsch cv. Christmas Feelings (CvF)] were used as plant materials in the study. Each of the solutions containing bacterial suspensions 52.5 (T1), 105 (T2), 210 (T3), 420 (T4) and 840 (T5) mL · L−1 of water was diluted 5 times with water and 200 mL · pot−1 was applied to the plant rhizosphere. This study revealed that positive changes incurred in plant height, main flower stem length, plant crown width, bract diameter, green leaf and bract leaf area, leaf total nitrogen content and nitrate reductase enzyme activity parameters in poinsettia plants with increasing doses of the bacterial formulation. This effect has reached the maximum level in the number of bracts, main flower stem length, bract diameter, nitrate reductase enzyme activity, plant fresh weight and maximal root length parameters with the T5 application which has the highest bacterial formulation concentration. The most efficient application of glutamine synthetase enzyme activity was determined as T4.

scholarly journals First Report of Xylella fastidiosa Associated with Oleander Leaf Scorch in Louisiana

Plant Disease ◽  
2010 ◽  
Vol 94 (2) ◽  
pp. 274-274 ◽  
Author(s):  
R. Singh ◽  
D. M. Ferrin ◽  
Q. Huang
Keyword(s):  
Baton Rouge ◽  
Xylella Fastidiosa ◽  
Free Water ◽  
Nerium Oleander ◽  
Bacterial Disease ◽  
Sterile Water ◽  
Dna Encoding ◽  
First Report ◽  
Leaf Scorch ◽  
Pure Cultures

Oleander (Nerium oleander L.) is an evergreen shrub native to the Mediterranean Region and Southeast Asia. Despite being poisonous, it is a popular ornamental plant for use in landscapes, gardens, parks, roadsides, and highway medians. During the fall of 2008, several oleander plants with leaf scorch symptoms were observed at Arsenal Park in Baton Rouge, LA. Symptomatic oleander samples were also received from a commercial nursery in Baton Rouge, LA and a homeowner in Thibodeaux, LA. Symptoms resembled leaf scorch caused by Xylella fastidiosa Wells et al. and included chlorotic mottling of the leaves that started from the tips and margins and progressed toward the midribs. As disease developed, leaf tips and margins became necrotic. Severely infected plants defoliated and died. Leaf petioles from 13 samples (8 from Arsenal Park, 3 from the commercial nursery, and 2 from the homeowner) from symptomatic plants gave positive reactions for X. fastidiosa by ELISA (Agdia, Inc., Elkhart, IN). Leaf petioles from six healthy oleander plants gave a negative reaction for X. fastidiosa by ELISA. Isolation of X. fastidiosa was attempted from eight ELISA-positive and six ELISA-negative oleander samples. Leaf petioles weighing 0.05 g from each sample were used for isolation. The petioles were surface sterilized in 70% ethanol for 1.5 min and then in 2% sodium hypochlorite for 1.5 min, followed by three 1-min washes in sterile water. The petioles were chopped into small pieces under aseptic conditions and soaked in 500 μl sterile water for 30 min. One hundred microliters of the suspension were spread onto periwinkle wilt (PW) plates and incubated in the dark at 28°C. After incubation for 7 days, bacterial colonies typical of X. fastidiosa appeared on five of eight ELISA-positive sample plates. No colonies were observed on six ELISA-negative sample plates. Single colonies were transferred to fresh PW plates to obtain pure cultures. Bacterial colonies from five pure cultures were suspended in nuclease-free water and boiled for 10 min to obtain DNA. DNA from eight symptomatic and six healthy oleander plants was extracted with a DNeasy Plant Mini kit (Qiagen Inc., Valencia, CA) according to the manufacturer's guidelines. Primers (QHOLS-08 and QHOLS-05) (1) specific to the oleander strain of X. fastidiosa amplified a 274-bp portion of DNA from both symptomatic oleander tissues and pure culture of X. fastidiosa isolated from symptomatic tissue. No such amplification was observed in healthy tissue. These primers amplify a portion of DNA encoding a hypothetical protein of unknown function that has been shown to be unique to oleander strains of X. fastidiosa. The PCR product was sequenced and compared with the whole genome shotgun sequence of the oleander strain Ann-1 of X. fastidiosa (GenBank Accession No. AAAM03000099), which resulted in 100% identity with nucleotides 11343 to 11616 in contig 228. X. fastidiosa has been previously reported to cause oleander leaf scorch in California (3), Florida (4), and Texas (2). To our knowledge, this is the first report of X. fastidiosa associated with oleander leaf scorch in Louisiana, extending the geographic range of this important bacterial disease. References: (1) Q. Huang. Curr. Microbiol. 58:393, 2009. (2) Q. Huang et al. Plant Dis. 88:1049, 2004. (3) A. H. Purcell et al. Phytopathology 89:53, 1999. (4) R. L. Wichman et al. Plant Dis. 84:198, 2000.

scholarly journals Recent Advances in the Management of Pediatric Acute Myeloid Leukemia—Report of the Hungarian Pediatric Oncology-Hematology Group

Cancers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 5078
Author(s):  
Zsuzsanna Gaál ◽  
Zsuzsanna Jakab ◽  
Bettina Kárai ◽  
Anikó Ujfalusi ◽  
Miklós Petrás ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Pediatric Oncology ◽  
Myeloid Leukemia ◽  
International Study ◽  
Diagnostic Procedures ◽  
Study Groups ◽  
International Standards ◽  
Hematopoietic Stem ◽  
Pediatric Acute Myeloid Leukemia ◽  
Acute Myeloid

Outcome measures of pediatric acute myeloid leukemia (AML) improved considerably between 1990 and 2011 in Hungary. Since 2012, efforts of the Hungarian Pediatric Oncology-Hematology Group (HPOG) included the reduction in the number of treatment centers, contemporary diagnostic procedures, vigorous supportation, enhanced access to hematopoietic stem cell transplantation (HSCT), and to targeted therapies. The major aim of our study was to evaluate AML treatment results of HPOG between 2012 and 2019 with 92 new patients registered (52 males, 40 females, mean age 7.28 years). Two periods were distinguished: 2012–2015 and 2016–2019 (55 and 37 patients, respectively). During these periods, 2 y OS increased from 63.6% to 71.4% (p = 0.057), and the 2 y EFS increased significantly from 56.4% to 68.9% (p = 0.02). HSCT was performed in 37 patients (5 patients received a second HSCT). We demonstrate advances in the diagnosis and treatment of acute promyelocytic leukemia (APL) in two cases. Early diagnosis and follow-up were achieved by multidimensional flow cytometry and advanced molecular methods. Both patients were successfully treated with all-trans retinoic acid and arsenic-trioxide, in addition to chemotherapy. In order to meet international standards of pediatric AML management, HPOG will further centralize treatment centers and diagnostic facilities and join efforts with international study groups.

scholarly journals Phytophthora × pelgrandis Causes Root and Collar Rot of Lavandula stoechas in Italy

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1091-1096 ◽  
Author(s):  
Roberto Faedda ◽  
Santa Olga Cacciola ◽  
Antonella Pane ◽  
András Szigethy ◽  
József Bakonyi ◽  
...  
Keyword(s):  
Parental Species ◽  
Random Amplified Polymorphic Dna ◽  
Natural Hybrid ◽  
Chain Reaction ◽  
Collar Rot ◽  
Potted Plants ◽  
Lavandula Stoechas ◽  
Hygienic Measures ◽  
Pathogenicity Tests ◽  
Polymerase Chain

In 2007, Phytophthora isolates with atypical morphological and biological characteristics were found associated with root and collar rot of potted plants of Stoechas lavender (Lavandula stoechas) in an ornamental nursery in Italy. A polyphasic approach, including morphological and cultural observations, sequencing the ITS-rDNA region, the Pheca and the mitochondrial coxI genes, multiplex PCRs with primers specific for P. nicotianae or P. cactorum, as well as random amplified polymorphic DNA–polymerase chain reaction, was used to characterize these isolates. On the basis of morpho-cultural and molecular analyses, the isolates from Stoechas lavender were identified as Phytophthora × pelgrandis, a natural hybrid of P. nicotianae × P. cactorum previously reported in other European countries, the Americas, and Taiwan, as a pathogen of ornamentals and loquat plants. In pathogenicity tests using potted plants of Stoechas lavender, the P. × pelgrandis isolates, similarly to the parental species P. nicotianae, induced the symptoms observed on plants with natural infections and were reisolated only from artificially inoculated plants. Dispersal of P. × pelgrandis on this host could exacerbate the damage caused by Phytophthora root and collar rot, of which the main causal agent presently is P. nicotianae on lavender in Europe. Application of hygienic measures is important to reduce the proliferation and spread of the Phytophthora hybrids.

scholarly journals First Report of Xylella fastidiosa in Nerium oleander in Costa Rica

Plant Disease ◽  
2008 ◽  
Vol 92 (8) ◽  
pp. 1249-1249 ◽  
Author(s):  
M. Montero-Astúa ◽  
G. Saborío-R. ◽  
C. Chacón-Díaz ◽  
W. Villalobos ◽  
C. M. Rodríguez ◽  
...  
Keyword(s):  
Costa Rica ◽  
Nested Pcr ◽  
Pure Culture ◽  
Xylella Fastidiosa ◽  
Central Valley ◽  
The United States ◽  
Mean Value ◽  
Immunofluorescence Assay ◽  
Nerium Oleander ◽  
Branch Dieback

Oleander (Nerium oleander L.) shrubs presenting mottling, leaf tip and margin scorch, short internodes, defoliation, and branch dieback were observed at different localities in the Central Valley in Costa Rica. Severity of the symptoms ranged widely, and most plants showed both diseased and healthy branches. In severe cases, entire sections of the plant were defoliated. Symptoms resembled those described for oleander leaf scorch (OLS) caused by the bacterium Xylella fastidiosa in the United States (3). This bacterium has been reported in coffee and citrus plants in Costa Rica. Sixty plants from five different places were sampled and tested using ELISA (Agdia Inc., Elkhart, IN) against X. fastidiosa. Thirty-five plants showed absorbance mean value of duplicate wells greater than the mean of control wells plus three times the standard deviation, and therefore were considered positive. Thirty-three of the sixty samples were processed for an immunofluorescence assay modified from Carbajal et al. (1) with antibody to X. fastidiosa (Agdia Inc.). Thirteen samples showed fluorescent rod-shaped bacilli with morphology similar to those observed from a pure culture of X. fastidiosa obtained from coffee. Ten of these thirteen samples were positive by ELISA. DNA extracts (2) from three of the oleander plants with high ELISA absorbance values were tested by nested PCR with primer pair 272-1/272-2 followed by the pair 272-1 int/272-2 int (4). Two of the samples were positive for the bacterium and one of the PCR products was cloned and sequenced in both directions (GenBank Accession No. EU009615). The negative (PCR mix) and positive (pure culture of X. fastidiosa isolated from grapevine) controls for nested-PCR were indeed negative and positive, respectively. The BLAST program was used to compare the sequence to the nucleotide collection (nr/nt) and Microbe Assembled Genomes databases in GenBank. All matches corresponded to X. fastidiosa sequences. The sequence showed 97% similarity with strains Found-4 (coffee strain from Brazil) and Found-5 (citrus strain from Brazil) and 96% similarity with strain Ann-1 from oleander in California. On the basis of serological, microscopic, and molecular detection of X. fastidiosa from oleander exhibiting symptoms of OLS similar to those reported in the literature, this pathogen likely is causing the symptoms we observed in Costa Rica. References: (1) D. Carbajal et al. Curr. Microbiol. 49:372, 2004. (2) M. J. Green et al. Plant Dis. 83:482, 1999. (3) Q. Huang et al. Plant Dis. 88:1049, 2004. (4) M. R. Pooler and J. S. Hartung. Curr. Microbiol. 31:377, 1995.

scholarly journals Transmission of Xylella fastidiosa to Oleander by the Glassywinged Sharpshooter, Homalodisca coagulata

HortScience ◽  
2000 ◽  
Vol 35 (7) ◽  
pp. 1265-1267 ◽  
Author(s):  
H.S. Costa ◽  
M.S. Blua ◽  
J.A. Bethke ◽  
R.A. Redak
Keyword(s):  
Plant Pathogen ◽  
Xylella Fastidiosa ◽  
Mortality Rates ◽  
Nerium Oleander ◽  
Plant Mortality ◽  
Higher Plant ◽  
Principal Vector ◽  
Homalodisca Coagulata ◽  
One Year ◽  
Bacterial Plant Pathogen

Studies were conducted to investigate the transmission of the oleander leaf scorch (OLS) pathogen to oleander (Nerium oleander L.) plants by sharpshooters. OLS is incited by a strain of the bacterial plant pathogen Xylella fastidiosa Well. The glassywinged sharpshooter, Homalodisca coagulata (Say), is a principal vector of this pathogen in California. In these studies, three cultivars of oleander were exposed to sharpshooters that had previously fed upon OLS-infected oleander plants. Sharpshooters were subsequently caged on healthy oleander plants individually or in groups of three. Plants were observed for symptoms of disease, and ELISA was used to test for the presence of X. fastidiosa. The probability of infection did not differ significantly when plants were inoculated with one insect (83%) or with three (94%). However, higher plant mortality rates were observed on plants inoculated with three insects, indicating that a greater number of infection sites may hasten plant death. Although all oleander cultivars were equally susceptible to inoculation by sharpshooters, `Ruby Lace' plants were less symptomatic and had a higher level of survival after one year than `Hardy Pink' and `Hardy Red'. When given a choice of the three cultivars to feed on, the number of insects feeding did not differ among cultivars at 24 or 48 hours after exposure.

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