Ericka E. Helmick

Ms. Ericka E. Helmick

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2018 in Plant Disease
Verified
Journal Article
Open access
Brian BahderBrian Bahder
Brian Bahder
EHEricka E. Helmick
Ericka E. Helmick
DMDe-Fen Mou
De-Fen Mou
NHNigel A. Harrison
Nigel A. Harrison
RDRobert Davis
Robert Davis
Phytoplasmas are an economically important group of plant pathogens that negatively impact a wide variety of plants in agricultural and natural ecosystems. In Florida, palm trees are essential elements in the nursery and landscaping industries that suffer from diseases caused by phytoplasmas that are related to each other but are classified in two different subgroups, 16SrIV-A and 16SrIV-D. In this study, a TaqMan assay was developed for digital polymerase chain reaction (dPCR) to detect both palm-infecting phytoplasmas found in Florida. When compared with real-time PCR assays and nested PCR assays, dPCR was capable of detecting the phytoplasmas at much lower concentrations than was possible by using real-time PCR and nested PCR. Additionally, the assay was capable of detecting 16SrIV-B phytoplasma as well as isolates representing the 16SrI and 16SrIII phytoplasma groups. Due to sequence identity of primer annealing regions across diverse phytoplasmas, the assay is likely to be successful for detection of a wide variety of phytoplasmas. The increased sensitivity of this dPCR assay over real-time PCR will allow for earlier detection of phytoplasma infection in palm trees, as well as for screening of salivary glands of candidate insect vector species. These advantages should aid timely management decisions to reduce disease spread and rapid determination of phytoplasma transmission by vectors.

1 October 2019 in Plant Disease
Verified
Journal Article
Closed access
Brian BahderBrian Bahder
Brian Bahder
NSNoemi Soto
Noemi Soto
EHEricka E. Helmick
Ericka E. Helmick
KDKishore Dey
Kishore Dey
LKLidia Komondy
Lidia Komondy
EGErica M. Goss
Erica M. Goss
The 16SrIV-D phytoplasma was first identified in Florida in 2006. Since its discovery, it has spread throughout most of the state. It is most prevalent in the central part of Florida, from Hillsborough County on the west coast to St. Lucie County on the east coast. The 16SrIV-D phytoplasma is the causal agent of lethal bronzing disease (LBD), which is also known as Texas Phoenix palm decline (TPPD). It affects a variety of common and economically important ornamental palm species as well as the native and ecologically important species, Sabal palmetto. It has spread into the southern portions of Florida, where the palm species diversity is higher. The aims of this survey were to document the spread of disease in terms of geographic and host range one decade after its introduction into Florida, and to assess the risk that LBD poses to the nursery and landscaping industries. The survey included samples received from stakeholders throughout the state, covering 18 counties, as well as a systematic sampling of palms at the Fort Lauderdale Research and Education Center (FLREC), where the disease is spreading actively. The findings of this survey resulted in the detection of LBD in eight new counties, including Collier, Hernando, Jefferson, Martin, Miami-Dade, Monroe, Seminole, and St. Johns, and the expansion of LBD into four new host species, Cocos nucifera, Livistona chinensis, Butia capitata, and Carpentaria acuminata. These findings are crucial for stakeholders because they highlight new hosts of 16SrIV-D phytoplasma and the geographic expansion of the disease, indicating that vigilance is needed when surveying declining palms.

26 November 2019 in Zootaxa
Verified
Journal Article
Open access
PDF file
Brian BahderBrian Bahder
Brian Bahder
CBCharles R. Bartlett
Charles R. Bartlett
EBEdwin A. Barrantes Barrantes
Edwin A. Barrantes Barrantes
MEMarco A. Zumbado Echavarria
Marco A. Zumbado Echavarria
AHAlessandra R. Humphries
Alessandra R. Humphries
MAMarina Ascunce
Marina Ascunce
Myxia belinda gen. et sp. nov. is established for a new taxon of Cixiidae in the tribe Oecleini collected from palms in Costa Rica. The new taxon was discovered while surveying palms for potential phytoplasma vectors. Placement in a new genus is supported by a 1,383 bp sequence of 18S that differs by 2.77% from Haplaxius, 5.20% from Myndus taffini, and 2.80% from Nymphomyndus caribbea. Intrageneric variation for 18S was found to be approximately 0.5% to 0.6% within Haplaxius. Generic level differences within the Oecleini for COI ranged from 15% to 17% with the novel taxon differing by about 16% from other genera. The new genus is most similar in appearance to Haplaxius but possesses striking sexual dimorphism, and the aedeagus is only partially surrounded by the phallobase (versus entirely enveloped in Haplaxius). The discovery of a novel taxon of cixiid on palms that is similar to Haplaxius is important because of the role that Haplaxius crudus plays in phytoplasma transmission in palm agro- and natural ecosystems.

18 December 2019 in Zootaxa
Verified
Journal Article
Open access
PDF file
WMWayne Myrie
Wayne Myrie
EHEricka E. Helmick
Ericka E. Helmick
CBCharles R. Bartlett
Charles R. Bartlett
Assunta BertacciniAssunta Bertaccini
Assunta Bertaccini
Brian BahderBrian Bahder
Brian Bahder
A new species of cixiid planthopper (Hemiptera: Fulgoroidea) in the genus Oecleus Stål, Oecleus mackaspringi sp. n., is described from Spring Garden, Jamaica. This new taxon is associated with coconut palm (Cocos nucifera L.) and was found while surveying palm plots with active cases of lethal yellowing (LY). This is the first report of the genus Oecleus from Jamaica. Sequence data for the COI gene and 18S gene are also provided.

1 September 2020 in Florida Entomologist
Verified
Journal Article
Open access
PDF file
DMDe-Fen Mou
De-Fen Mou
AHAlessandra R. Humphries
Alessandra R. Humphries
NSNoemi Soto
Noemi Soto
EHEricka E. Helmick
Ericka E. Helmick
MAMarina Ascunce
Marina Ascunce
BBBrian W. Bahder
Brian W. Bahder
Lethal bronzing disease is caused by the 16SrIV-D phytoplasma and is fatal to many palm species. This disease has caused significant economic losses to nursery and landscaping industries in Florida. As is the phloem-limited nature of phytoplasmas, the lethal bronzing disease phytoplasma is transmitted only by phloem-feeding insect vectors. However, the vector remains unconfirmed and this impedes the development of Integrated Pest Management programs that target vector populations. The primary objective of this study was to identify potential vectors of the 16SrIV-D phytoplasma in Florida by surveying auchenorrhynchans using sticky traps at the area where the disease is actively spreading, and screening the specimens for the presence of the phytoplasma. Cixiidae, Cicadellidae, Derbidae, and Membracidae insects were collected consistently during the 1-yr survey. The total number of a cixiid planthopper, Haplaxius crudus (Van Duzee) (Hemiptera: Cixiidae), was significantly higher than other insects that were collected on the traps. Of 3,734 specimens tested by nested polymerase chain reaction, approximately 0.672% of the H. crudus specimens and 1 unidentified leafhopper (Cicadellidae sp.) tested positive for the16SrIV-D phytoplasma. The 16S sequences amplified from the positive specimens were confirmed by sequencing and phylogenetic analysis. Based on the population survey and the polymerase chain reaction assay results, we suggest that H. crudus is the potential vector of the 16SrIV-D phytoplasma. However, the vector competency of H. crudus needs to be further investigated due to the possibility of feeding residue being detected. The study has important implication for current lethal bronzing disease management by monitoring and controlling vector candidates in disease areas.

20 November 2024 in Ecology and Evolution
Verified
Journal Article
Open access
MMMelissa A. Miller
Melissa A. Miller
MBMelody Bloch
Melody Bloch
SBSergio A. Balaguera‐Reina
Sergio A. Balaguera‐Reina
KOKevin A. Olejniczak
Kevin A. Olejniczak
CPCynthia A. Fussell Persaud
Cynthia A. Fussell Persaud
Brian BahderBrian Bahder
Brian Bahder
Florida, USA is a hotspot of biological invasions with over 500 non‐native species reported. Reptiles encompass most of the non‐native wildlife with over 50 species established, many of which are sympatric and are identified as invasive due to their impacts to the environment, economy, and human health and safety. Reports of new non‐native reptiles occur, and many established non‐native reptiles continue to expand their ranges in Florida, increasing the need for multitaxa detection and monitoring capabilities. Invasive constrictor snakes are a primary focus of management efforts due to life history traits that favor successful establishment and dispersal in Florida as well as their impacts to native wildlife and Everglades restoration efforts. While traditional survey methods that rely on visual detections fail to reliably detect invasive constrictors, environmental DNA (eDNA) has proven to be a promising method for detection of cryptic and rare species across the landscape. To address emerging needs for multispecies detection and monitoring in Florida, we developed the first tetraplex dPCR assay designed for detection of four species of invasive constrictor snakes, including Burmese pythons ( Python bivittatus ), northern African pythons ( P. sebae ), boa constrictors ( Boa constrictor ), and rainbow boas ( Epicrates cenchria ). In this tetraplex assay, no cross‐amplification across species was documented. This assay serves as a valuable tool for faster and more accurate monitoring efforts of these invasive species in South Florida. Additionally, eDNA samples comprised of soil and water both tested positive for Burmese python DNA under controlled and semicontrolled conditions with DNA being detectable up to 2‐weeks post removal in soil samples. Water samples yielded positive detection as quickly as 5 min after exposure to the organism. These data highlight the utility and sensitivity of this protocol for eDNA monitoring.