scholarly journals First Report of Phytoplasmas Infecting Watercress in Hawaii

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 331-331 ◽  
Author(s):  
W. B. Borth ◽  
R. T. Hamasaki ◽  
D. Ogata ◽  
S. K. Fukuda ◽  
J. S. Hu
Keyword(s):  
Leaf Size ◽  
Nutritional Deficiencies ◽  
Aster Yellows ◽  
Pcr Products ◽  
Mite Feeding ◽  
Efficient Vector ◽  
Phytoplasma Infection ◽  
Macrosteles Quadrilineatus ◽  
Aster Leafhopper ◽  
Aster Yellows Phytoplasma

Symptoms of leaf yellowing, reduced leaf size, and witches'-brooms have recently been observed affecting watercress (Nasturtium microphyllum Boen. × Rcbh.) in Hawaii. These symptoms are followed by the collapse of affected plants. This condition has led to 80 to 90% losses for one of the largest watercress farms on Oahu and is now affecting other watercress farms in the area. Nutritional deficiencies or toxicities, water salinity, and insect or mite feeding damage were investigated but could not be implicated in the etiology of this syndrome. Eighteen watercress plants with early yellowing or advanced symptoms and nine symptomless plants were analyzed for phytoplasma infection using polymerase chain reaction (PCR) assays with primer pairs P1/Tint or P1/P7 (4). Amplicons of the expected sizes were produced from all symptomatic plants, whereas no products were amplified from symptomless plants. Sequence analysis of the cloned PCR products confirmed their phytoplasma origin and indicated that the watercress was infected with a phytoplasma most similar to SAY (2), a severe strain of western aster yellows phytoplasma previously classified as a 16SrI-B group member (3). Leafhoppers collected from an affected watercress planting have been identified as the aster leafhopper (Macrosteles quadrilineatus Fbs.) This species is the most efficient vector of the aster yellows phytoplasma and had not been previously recorded in Hawaii. The only other phytoplasma disease known in Hawaii prior to this report is Dodonaea yellows (1), which affects one of the most common native plants (Dodonaea viscosa (L.) Jacq.) in dry upland forests on all the islands. Dodonaea yellows, however, has been attributed to an X-disease (16SrIII) group phytoplasma. The occurrence of an aster yellows group phytoplasma in watercress, a previously unrecorded host, and the presence of a very efficient vector, M. quadrilineatus, poses a serious threat to the production of other vegetable and floral crops in Hawaii. References: (1) W. Borth et al. Plant Dis. 79:1094, 1995. (2) C. Kuske and B. Kirkpatrick. Int. J. Syst. Bacteriol. 42:226, 1992. (3) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (4) C. Smart et al. Appl. Environ. Microbiol. 62:2988, 1996.

scholarly journals Identifying Leafhopper Targets for Controlling Aster Yellows in Carrots and Celery

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 411
Author(s):  
Patrick T. Stillson ◽  
Zsofia Szendrei
Keyword(s):  
Abundant Species ◽  
Additional Species ◽  
Aster Yellows ◽  
Crop Fields ◽  
Vegetable Farmers ◽  
Phytoplasma Infection ◽  
Macrosteles Quadrilineatus ◽  
Aster Leafhopper ◽  
Aster Yellows Phytoplasma ◽  
Species Being

Aster yellows phytoplasma (Candidatus Phytoplasma asteris) is a multi-host plant pathogen and is transmitted by at least 24 leafhopper species. Pathogen management is complex and requires a thorough understanding of vector dynamics. In the American Midwest, aster yellows is of great concern for vegetable farmers who focus on controlling one vector, Macrosteles quadrilineatus—the aster leafhopper. However, vegetable-associated leafhopper communities can be diverse. To investigate whether additional species are important aster yellows vectors, we surveyed leafhopper communities at commercial celery and carrot farms in Michigan from 2018 to 2019 and conducted real-time PCR to determine infection status. Leafhoppers were collected within crop fields and field edges and identified with DNA barcoding. Overall, we collected 5049 leafhoppers, with the most abundant species being M. quadrilineatus (57%) and Empoasca fabae—the potato leafhopper (23%). Our results revealed the most abundant aster yellows vector in Michigan in both crops is M. quadrilineatus, but we also found that E. fabae may be a potential vector for this pathogen. While several taxa reside in and near these crops, we did not find strong evidence that they contribute to phytoplasma infection. These findings indicate that M. quadrilineatus should be the primary target for controlling this pathogen.

scholarly journals Genetic Variation Among Geographically Disparate Isolates of Aster Yellows Phytoplasma in the Contiguous United States

2020 ◽  
Vol 113 (2) ◽  
pp. 604-611 ◽  
Author(s):  
Justin Clements ◽  
Marjorie Garcia ◽  
Benjamin Bradford ◽  
Linda Crubaugh ◽  
Shannon Piper ◽  
...  
Keyword(s):  
United States ◽  
Aster Yellows ◽  
Effector Genes ◽  
Northern Latitudes ◽  
Similarities And Differences ◽  
Northern United States ◽  
Macrosteles Quadrilineatus ◽  
Aster Leafhopper ◽  
Aster Yellows Phytoplasma ◽  
Insight Into

Abstract Aster Yellows phytoplasma (AYp; Candidatus Phytoplasma asteris) is associated with diseases of herbaceous plants, including ornamentals and important commercial vegetable and grain crops. The aster leafhopper (ALH; Macrosteles quadrilineatus Forbes) is the predominant vector of these bacteria, though other leafhopper species can acquire and transmit AYp. Potentially inoculative leafhoppers are reported to overwinter in the southern United States and migrate to northern latitudes in the spring. Examining the genetic similarities and differences in AYp associated with southern and northern populations of ALH may provide insight into the role that migrating ALH play in AYp disease development. To investigate similarities among geographically distinct populations of ALH and characterize the variation in AYp associated within these populations, we identified genetic variations in subgroup designation and the relative proportions of secreted AY-WB proteins from field-collected populations of AYp isolated from ALH from select locations in the southern (Arkansas, Kansas, Oklahoma, and Texas) and the northern United States (Wisconsin) in 2016, 2017, and 2018. Isolated phytoplasma were tested for variation of AYp genotypes, numbers of potentially inoculative (AYp-positive) ALH, and presence of specific AYp virulence (effector) genes. Geographically distinct populations of ALH collected in northern and southern regions were similar in CO1 genotype but carried different proportions of AYp genotypes. While similar AYp strains were detected in geographically distinct locations, the proportion of each genotype varied over time.

scholarly journals Seasonal Patterns of Aster Leafhopper (Hemiptera: Cicadellidae) Abundance and Aster Yellows Phytoplasma Infectivity in Wisconsin Carrot Fields

2013 ◽  
Vol 42 (3) ◽  
pp. 491-502 ◽  
Author(s):  
K. E. Frost ◽  
P. D. Esker ◽  
R. Van Haren ◽  
L. Kotolski ◽  
R. L. Groves
Keyword(s):  
Seasonal Patterns ◽  
Aster Yellows ◽  
Aster Leafhopper ◽  
Aster Yellows Phytoplasma

scholarly journals First Report of an Aster Yellows Phytoplasma Associated with Cabbage in Southern Texas

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 447-447 ◽  
Author(s):  
I.-M. Lee ◽  
R. A. Dane ◽  
M. C. Black ◽  
Noel Troxclair
Keyword(s):  
16S Rdna ◽  
Nested Pcr ◽  
Restriction Enzymes ◽  
Diagnostic Procedures ◽  
Acid Extraction ◽  
Insect Vector ◽  
Aster Yellows ◽  
First Report ◽  
Pcr Products ◽  
Aster Yellows Phytoplasma

In early spring 2000 carrot crops in southwestern Texas were severely infected by an outbreak of phyllody associated with aster yellows phytoplasma. Cabbage crops that had been planted adjacent to these carrot fields began to display previously unobserved symptoms characteristic of phytoplasma infection. Symptoms included purple discoloration in leaf veins and at the outer edges of leaves on cabbage heads. Proliferation of sprouts also occurred at the base of the stem and between leaf layers of some plants, and sprouts sometimes continued to proliferate on extended stems. About 5% of cabbage plants in the field exhibited these symptoms. Two symptomless and four symptomatic cabbage heads were collected in early April from one cabbage field. Veinal tissues were stripped from each sample and used for total nucleic acid extraction. To obtain specific and sufficient amount of PCR products for analysis, nested PCR was performed by using primer pairs (first with P1/P7 followed by R16F2n/R16R2) (1,2) universal for phytoplasma detection. A specific 16S rDNA fragment (about 1.2 kb) was strongly amplified from the four symptomatic but not from the two asymptomatic samples. The nested PCR products obtained from the four symptomatic samples were then analyzed by restriction fragment length polymorphism (RFLP) using the restriction enzymes MseI, HhaI, and HpaII, and the RFLP patterns were compared to the published patterns of known phytoplasmas (1). The resulting RFLP patterns were identical to those of a phytoplasma belonging to subgroup B of the aster yellows phytoplasma group (16SrI). These RFLP patterns were also evident in putative restriction sites observed in a 1.5 kbp nucleotide sequence of the 16S rDNA. This is the first report of aster yellows phytoplasma associated disease symptoms in cabbage in Texas. The occurrence of cabbage proliferation coincided with the presence of high populations of the insect vector, aster leafhopper. References: (1) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998. (2) B. Schneider et al. 1995. Molecular and Diagnostic Procedures in Mycoplasmology, Vol. I. Academic Press, San Diego, CA.

scholarly journals Factors Influencing Aster Leafhopper (Hemiptera: Cicadellidae) Abundance and Aster Yellows Phytoplasma Infectivity in Wisconsin Carrot Fields

2013 ◽  
Vol 42 (3) ◽  
pp. 477-490 ◽  
Author(s):  
K. E. Frost ◽  
P. D. Esker ◽  
R. Van Haren ◽  
L. Kotolski ◽  
R. L. Groves
Keyword(s):  
Aster Yellows ◽  
Factors Influencing ◽  
Aster Leafhopper ◽  
Aster Yellows Phytoplasma

scholarly journals First report of aster yellows phytoplasma infection of marigold plants in Hungary

2018 ◽  
Vol 100 (2) ◽  
pp. 327-327 ◽  
Author(s):  
Orsolya Viczián ◽  
Emese Kiss ◽  
Mária Szabó ◽  
Emese Mergenthaler
Keyword(s):  
Aster Yellows ◽  
First Report ◽  
Phytoplasma Infection ◽  
Aster Yellows Phytoplasma

scholarly journals Candidatus (Ca.) phytoplasma asteris subgroups display distinct disease progression dynamics during the carrot growing season

2020 ◽  
Author(s):  
Justin Clements ◽  
Benjamin Z. Bradford ◽  
Marjorie Garcia ◽  
Shannon Piper ◽  
Weijie Huang ◽  
...  
Keyword(s):  
Disease Progression ◽  
Temporal Dynamics ◽  
Insect Pest ◽  
Management Strategies ◽  
Bacterial Pathogen ◽  
Growing Season ◽  
Aster Yellows ◽  
Crop Density ◽  
Aster Leafhopper ◽  
Aster Yellows Phytoplasma

AbstractAster Yellows phytoplasma (AYp; Candidatus (Ca.) Phytoplasma asteris) is an obligate bacterial pathogen that is the causative agent of multiple diseases in herbaceous plants. While this phytoplasma has been examined in depth for its disease characteristics, knowledge about the spatial and temporal dynamics of pathogen spread is lacking. The phytoplasma is found in plant’s phloem and is vectored by leafhoppers (Cicadellidae: Hemiptera), including the aster leafhopper, Macrosteles quadrilineatus Forbes. The aster leafhopper is a migratory insect pest that overwinters in the southern United States, and historical data suggest these insects migrate from southern overwintering locations to northern latitudes annually, transmitting and driving phytoplasma infection rates as they migrate. A more in-depth understanding of the spatial, temporal and genetic determinants of Aster Yellows disease progress will lead to better integrated pest management strategies for Aster Yellows disease control. Carrot, Daucus carota L., plots were established at two planting densities in central Wisconsin and monitored during the 2018 growing season for Aster Yellows disease progression. Symptomatic carrots were sampled and assayed for the presence of the Aster Yellows phytoplasma. Aster Yellows disease progression was determined to be significantly associated with calendar date, crop density, location within the field, and phytoplasma subgroup.

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