Mike Irey - Academia.edu (original) (raw)

Papers by Mike Irey

Journal of citrus pathology, 2014

International Organization of Citrus Virologists Conference proceedings, 2000

Acta horticulturae, Jul 1, 2011

Clover yellow vein virus (ClYVV), Bidens mottle virus (BiMoV) and Apium virus Y (ApVY) were ident... more Clover yellow vein virus (ClYVV), Bidens mottle virus (BiMoV) and Apium virus Y (ApVY) were identified in Ammi majus in south Florida cut flower production areas in 2005 and/or 2007. To the best of our knowledge, these results are the first report of ClYVV and BiMoV infection of A. majus in North America and the first report of ApVY in North America. Common weeds in Florida are known reservoir hosts for ClYVV including white clover (Trifolium repens) and for BiMoV including Spanish needles (Bidens pilosa) and tropical soda apple (Solanum viarum). Detection of ClYVV and BiMoV in other ornamental crops in Florida suggests that these viruses pose a broader risk to ornamental production.

International Organization of Citrus Virologists Conference proceedings, 2002

Reverse transcription polymerase chain reaction (RT-PCR) has been incorporated as an adjunct to F... more Reverse transcription polymerase chain reaction (RT-PCR) has been incorporated as an adjunct to Florida's biological indexing program for viroids, especially to test for Citrus viroid II (CVd-II) and all viroids where rapid results are needed. The sensitivity of RT-PCR for testing of composite samples was evaluated using 5, 10, 25, 50, 100 and 200 tree composites. Single positive trees were detected consistently in the 5-and 10-tree composite samples; these 5 and 10 tree composites are routinely used to test for CVd-II using Etrog citron indicators. When a composite sample is found to be positive, the individual trees comprising the composite are retested. Viroid infected source trees, identified by biological indexing, were tested by RT-PCR for CVd-II, Citrus viroid III (CVd-III) and Citrus exocortis viroid (CEVd) using tissue collected from both the citron indicators and the corresponding field trees to evaluate the validity of RT-PCR testing. Reliable detection of CVd-II, III and CEVd from field samples by RT-PCR is important for shortening testing time and reducing costs. RT-PCR also allows rapid diagnosis of field samples and testing of trees near a citrus canker quarantine zone without exposing our biological test facilities to potential sources of citrus canker inoculum. Agarose gel electrophoresis was adequate for visualization of CVd-II RT-PCR products, but the sensitivity of CEVd and CVd-III detection has been increased by visualization of RT-PCR products by using either polyacrylamide gels with GelStar stain or Metaphor agarose gels. Improved primers have increased our confidence in CEVd detection by RT-PCR. Screening PCR products from 32 Florida viroid isolates causing a mild citron reaction with oligonucleotide probes specific for CVd-IIIa or CVd-IIIb revealed that CVd-IIIa and IIIb occur both separately and as mixed infections.

Proceedings of the Florida State Horticultural Society, Dec 1, 2012

Mention of a trademark or proprietary product is for identification only and does not imply a gua... more Mention of a trademark or proprietary product is for identification only and does not imply a guarantee or warranty of the product by the U.S. Department of Agriculture. The U.S. Department of Agriculture prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. *Corresponding author; phone: (772) 462-5979; email: Liz.Baldwin@ars.usda.gov Handling & Processing Section

Phytopathology, Jun 1, 2010

International Organization of Citrus Virologists Conference proceedings, 2002

A practical approach to the detection of the three common citrus viroids in Florida citrus from f... more A practical approach to the detection of the three common citrus viroids in Florida citrus from field-collected tissue by RT-PCR was developed and tested. Reverse transcriptions were done with total nucleic acid extracts prepared by a SDS-potassium acetate extraction of small amounts of tissue pulverized in Tris buffer. PCR amplifications were done using previously described primer pairs specific for Citrus exocortis viroid (CEVd), Citrus viroid II (CVd-II) (Hop stunt viroid) and Citrus viroid III (CVd-III), and the products were analyzed by agarose gel electrophoresis. Effects of cultivar, tissue location and sampling time were investigated. CEVd, CVd-II, and CVd-III were all consistently detected in tissue from experimentally infected orange, lemon, and lime cultivars, but detection from grapefruit and mandarins was less consistent, especially for CEVd. CEVd and CVd-II were not detected in Meiwa kumquat and detection of CVd-III was rare. Bark tissue from woody, budwood-sized twigs was the best tissue source, and samples collected in warm weather yielded better results than those collected in winter. Field surveys of several hundred trees in commercial groves and test plots with varying viroid profiles were conducted. The correlation between results from RT-PCR and biological indexing exceeded 90%. RT-PCR was especially effective for detection of CVd-II, the citrus viroid most difficult to detect biologically or by sequential PAGE. Several isolates that caused moderate symptoms in Etrog citron were not amplified by our CEVd, CVd-II and CVd-III primers. One was identified as Citrus viroid IV , and this is the first report of this viroid in Florida. The others were identified as sequence variants of CVd-III. The methods developed have been used successfully by personnel in three different laboratories.

Epidemics, Jun 1, 2012

A key challenge for plant pathologists is to develop efficient methods to describe spatial patter... more A key challenge for plant pathologists is to develop efficient methods to describe spatial patterns of disease spread accurately from a limited number of samples. Knowledge of disease spread is essential for informing and justifying plant disease management measures. A mechanistic modelling approach is adopted for disease mapping which is based on disease dispersal gradients and consideration of host pattern. The method is extended to provide measures of uncertainty for the estimates of disease at each host location. In addition, improvements have been made to increase computational efficiency by better initialising the disease status of unsampled hosts and speeding up the optimisation process of the model parameters. These improvements facilitate the practical use of the method by providing information on: (a) mechanisms of pathogen dispersal, (b) distance and pattern of disease spread, and (c) prediction of infection probabilities for unsampled hosts. Two data sets of disease observations, Huanglongbing (HLB) of citrus and strawberry powdery mildew, were used to evaluate the performance of the new method for disease mapping. The result showed that our method gave better estimates of precision for unsampled hosts, compared to both the original method and spatial interpolation. This enables decision makers to understand the spatial aspects of disease processes, and thus formulate regulatory actions accordingly to enhance disease control.

Agrosystems, Geosciences & Environment

Industrial hemp (Cannabis sativa L.) commercialization in Florida is mainly challenged by the lac... more Industrial hemp (Cannabis sativa L.) commercialization in Florida is mainly challenged by the lack of suitable essential oil hemp cultivars with Δ‐9‐tetrahydrocannabinol (THC) concentration below the legal threshold. However, previous studies have only evaluated cannabidiol (CBD)‐dominant industrial hemp cultivars but not the cultivars primarily grown for cannabigerol (CBG) production. Hence, field trials were conducted using two CBG dominant cultivars adapted in Kentucky (CBG Gold) and Colorado (Panacea) at three experimental farms located at Okeechobee (Lykes) and Clewiston (Townsite and Ritta) in southern Florida with three planting dates from late April to late June under two different soil types (sandy soil at Lykes and Townsite, and organic soil at Ritta). CBG, CBD, and THC concentrations were analyzed in developing flowers harvested at weekly intervals beginning 2 weeks after flowering until crop maturity. Location and planting date had some effect on cannabinoids profile, bu...

Agrosystems, Geosciences & Environment

Agronomy

Hemp production has been permitted as a new agricultural commodity in Florida and may serve as a ... more Hemp production has been permitted as a new agricultural commodity in Florida and may serve as a potential rotational crop. Field trials were conducted in the Everglades Agricultural Region with multiple varieties planted at different dates. Data were collected on plant growth parameters, final biomass at harvest, and temporal cannabidiol (CBD) and Δ-9-tetrahydrocannabinol (THC) content in developing flowers. Results showed that at the United States Sugar Corporation (USSC) location, the BaOX variety had higher biomass compared to other varieties and at Everglades Research and Education Center (EREC), varieties ACDC and Cherry wine recorded the highest biomass compared to other varieties. Moreover, plant growth parameters such as plant height, canopy cover and SPAD were significantly affected by variety and planting date. Total CBD and THC content in plants increased over time for most varieties except for Early bird and Cherry abacus under second planting. There was a significantly...

Frontiers in Plant Science

Florida orange trees have been affected by huanglongbing (HLB) for more than a decade. To allevia... more Florida orange trees have been affected by huanglongbing (HLB) for more than a decade. To alleviate disease-caused tree decline, maintain fruit productivity, and reduce disease transmission, enhanced foliar spray programs combining vector control and nutritional supplementation have been applied to healthy and diseased trees. The aim of this research was to discover if the various foliar sprays affect fruit peel oil chemical components. In this study, “Valencia” orange trees, with or without HLB (HLB±), were treated with the grower standard program (control, C) or one of four proprietary enhanced foliar spray programs (N1, N2, N3, and N4) over 16 months. Compared with HLB−, HLB+ samples had lower concentrations of typical peel oil components, including valencene, octanal, and decanal, and were abundant in oxidative/dehydrogenated terpenes, such as carvone and limonene oxide. However, limonene, the dominant component, was not affected by any treatment. Control and three out of four e...

Proceedings of the 13th Conference of the International Organization of Citrus Virologists, Riverside, USA: International Organization of Citrus Virologists, University of California, Riverside, USA, 1996

and California were used to develop models for increase and spread of citrus tristeza virus (CW).... more and California were used to develop models for increase and spread of citrus tristeza virus (CW). In locations where the melon aphid, Aphis gossypii Glover, was the predominant vector, C W progressed from low (-5%) to high (-95%) levels in 8-15 yr. In contrast, where the brown citrus aphid, Toxoptera citricida (Kirkaldy), was predominant, this same increase often occurred in only 2-4 yr. Where the melon aphid was the predominant vector, new infections were diffuse and not closely associated with existing infected trees but rather with trees several tree spaces distant. Where both species coexisted, the brown citrus aphid was the dominant species. In this situation, spread to trees immediately adjacent to existing infections was common which resulted in aggregates of CTV-infected trees along with longer distance spread in some instances. C W infections were generally diffuse or quite aggregated where the melon aphid or the brown citrus aphid was the predominant species, respectively. Thus, aphid species greatly influenced the rate and patterns of CTV epidemics, and their presencetabsence was important to predict how CTV will increase in time and space.

Journal of Citrus Pathology, 2014

Journal of Theoretical Biology, 2020

The Citrus tristeza virus (CTV) is one of the most economically devastating citrus diseases world... more The Citrus tristeza virus (CTV) is one of the most economically devastating citrus diseases worldwide. The spread of CTV in eastern Spain was studied by Gottwald et al. with the goal of determining the spatio-temporal mechanisms of spread. Since the subjects in this study are individual trees, it is natural to think of infections as Bernoulli trials. This approach is difficult however, due to the spatial and temporal dependence of the observations. Consequently, a system of ordinary differential equations (ODE) was used to model the probabilities of infection as well as the spatial and temporal dependence. Given the parameters in the ODE, the probabilities of infection are treated as conditionally independent. Using the conditional independence we then specify the joint likelihood function as a Poisson binomial distribution. For the purpose of model selection and hypothesis testing we, employed accumulated prediction error (APE) which has connections to both Bayesian and frequentist frameworks. We demonstrated the robustness of our method in accounting for spatio-temporal dependencies in the data by accurately predicting the spatial distribution of the disease through Join Counts.

LWT - Food Science and Technology, 2015

Plant Disease, 2006

Ammi majus L., a member of the Apiaceae and also known as large bullwort, false Queen Anne's ... more Ammi majus L., a member of the Apiaceae and also known as large bullwort, false Queen Anne's lace, or bishop's-weed, is frequently used in the floral trade to add a lacey look to floral bouquets. A. majus is native to the Mediterranean Region but it is cultivated in major growing areas including Holland, Israel, the United Kingdom, and the United States. During March 2005, virus-like symptoms including mosaic, generalized chlorosis, vein clearing, interveinal chlorosis, and leaf rugosity were observed in nearly all field-grown A. majus plants at two locations in Martin County, Florida. Inclusion body morphology suggested the presence of one or more potyviruses in the symptomatic plants. Potyvirus infection was confirmed in 11 symptomatic plants using a commercially available enzyme-linked immunosorbent assay (ELISA) kit (Agdia, Elkhart, IN). Nucleotide and deduced amino acid sequences of a 1,625-bp region of one of the reverse transcription-polymerase chain reaction products...

European Journal of Plant Pathology, 2014

Journal of citrus pathology, 2014

International Organization of Citrus Virologists Conference proceedings, 2000

Acta horticulturae, Jul 1, 2011

Clover yellow vein virus (ClYVV), Bidens mottle virus (BiMoV) and Apium virus Y (ApVY) were ident... more Clover yellow vein virus (ClYVV), Bidens mottle virus (BiMoV) and Apium virus Y (ApVY) were identified in Ammi majus in south Florida cut flower production areas in 2005 and/or 2007. To the best of our knowledge, these results are the first report of ClYVV and BiMoV infection of A. majus in North America and the first report of ApVY in North America. Common weeds in Florida are known reservoir hosts for ClYVV including white clover (Trifolium repens) and for BiMoV including Spanish needles (Bidens pilosa) and tropical soda apple (Solanum viarum). Detection of ClYVV and BiMoV in other ornamental crops in Florida suggests that these viruses pose a broader risk to ornamental production.

International Organization of Citrus Virologists Conference proceedings, 2002

Reverse transcription polymerase chain reaction (RT-PCR) has been incorporated as an adjunct to F... more Reverse transcription polymerase chain reaction (RT-PCR) has been incorporated as an adjunct to Florida's biological indexing program for viroids, especially to test for Citrus viroid II (CVd-II) and all viroids where rapid results are needed. The sensitivity of RT-PCR for testing of composite samples was evaluated using 5, 10, 25, 50, 100 and 200 tree composites. Single positive trees were detected consistently in the 5-and 10-tree composite samples; these 5 and 10 tree composites are routinely used to test for CVd-II using Etrog citron indicators. When a composite sample is found to be positive, the individual trees comprising the composite are retested. Viroid infected source trees, identified by biological indexing, were tested by RT-PCR for CVd-II, Citrus viroid III (CVd-III) and Citrus exocortis viroid (CEVd) using tissue collected from both the citron indicators and the corresponding field trees to evaluate the validity of RT-PCR testing. Reliable detection of CVd-II, III and CEVd from field samples by RT-PCR is important for shortening testing time and reducing costs. RT-PCR also allows rapid diagnosis of field samples and testing of trees near a citrus canker quarantine zone without exposing our biological test facilities to potential sources of citrus canker inoculum. Agarose gel electrophoresis was adequate for visualization of CVd-II RT-PCR products, but the sensitivity of CEVd and CVd-III detection has been increased by visualization of RT-PCR products by using either polyacrylamide gels with GelStar stain or Metaphor agarose gels. Improved primers have increased our confidence in CEVd detection by RT-PCR. Screening PCR products from 32 Florida viroid isolates causing a mild citron reaction with oligonucleotide probes specific for CVd-IIIa or CVd-IIIb revealed that CVd-IIIa and IIIb occur both separately and as mixed infections.

Proceedings of the Florida State Horticultural Society, Dec 1, 2012

Mention of a trademark or proprietary product is for identification only and does not imply a gua... more Mention of a trademark or proprietary product is for identification only and does not imply a guarantee or warranty of the product by the U.S. Department of Agriculture. The U.S. Department of Agriculture prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. *Corresponding author; phone: (772) 462-5979; email: Liz.Baldwin@ars.usda.gov Handling & Processing Section

Phytopathology, Jun 1, 2010

International Organization of Citrus Virologists Conference proceedings, 2002

A practical approach to the detection of the three common citrus viroids in Florida citrus from f... more A practical approach to the detection of the three common citrus viroids in Florida citrus from field-collected tissue by RT-PCR was developed and tested. Reverse transcriptions were done with total nucleic acid extracts prepared by a SDS-potassium acetate extraction of small amounts of tissue pulverized in Tris buffer. PCR amplifications were done using previously described primer pairs specific for Citrus exocortis viroid (CEVd), Citrus viroid II (CVd-II) (Hop stunt viroid) and Citrus viroid III (CVd-III), and the products were analyzed by agarose gel electrophoresis. Effects of cultivar, tissue location and sampling time were investigated. CEVd, CVd-II, and CVd-III were all consistently detected in tissue from experimentally infected orange, lemon, and lime cultivars, but detection from grapefruit and mandarins was less consistent, especially for CEVd. CEVd and CVd-II were not detected in Meiwa kumquat and detection of CVd-III was rare. Bark tissue from woody, budwood-sized twigs was the best tissue source, and samples collected in warm weather yielded better results than those collected in winter. Field surveys of several hundred trees in commercial groves and test plots with varying viroid profiles were conducted. The correlation between results from RT-PCR and biological indexing exceeded 90%. RT-PCR was especially effective for detection of CVd-II, the citrus viroid most difficult to detect biologically or by sequential PAGE. Several isolates that caused moderate symptoms in Etrog citron were not amplified by our CEVd, CVd-II and CVd-III primers. One was identified as Citrus viroid IV , and this is the first report of this viroid in Florida. The others were identified as sequence variants of CVd-III. The methods developed have been used successfully by personnel in three different laboratories.

Epidemics, Jun 1, 2012

A key challenge for plant pathologists is to develop efficient methods to describe spatial patter... more A key challenge for plant pathologists is to develop efficient methods to describe spatial patterns of disease spread accurately from a limited number of samples. Knowledge of disease spread is essential for informing and justifying plant disease management measures. A mechanistic modelling approach is adopted for disease mapping which is based on disease dispersal gradients and consideration of host pattern. The method is extended to provide measures of uncertainty for the estimates of disease at each host location. In addition, improvements have been made to increase computational efficiency by better initialising the disease status of unsampled hosts and speeding up the optimisation process of the model parameters. These improvements facilitate the practical use of the method by providing information on: (a) mechanisms of pathogen dispersal, (b) distance and pattern of disease spread, and (c) prediction of infection probabilities for unsampled hosts. Two data sets of disease observations, Huanglongbing (HLB) of citrus and strawberry powdery mildew, were used to evaluate the performance of the new method for disease mapping. The result showed that our method gave better estimates of precision for unsampled hosts, compared to both the original method and spatial interpolation. This enables decision makers to understand the spatial aspects of disease processes, and thus formulate regulatory actions accordingly to enhance disease control.

Agrosystems, Geosciences & Environment

Industrial hemp (Cannabis sativa L.) commercialization in Florida is mainly challenged by the lac... more Industrial hemp (Cannabis sativa L.) commercialization in Florida is mainly challenged by the lack of suitable essential oil hemp cultivars with Δ‐9‐tetrahydrocannabinol (THC) concentration below the legal threshold. However, previous studies have only evaluated cannabidiol (CBD)‐dominant industrial hemp cultivars but not the cultivars primarily grown for cannabigerol (CBG) production. Hence, field trials were conducted using two CBG dominant cultivars adapted in Kentucky (CBG Gold) and Colorado (Panacea) at three experimental farms located at Okeechobee (Lykes) and Clewiston (Townsite and Ritta) in southern Florida with three planting dates from late April to late June under two different soil types (sandy soil at Lykes and Townsite, and organic soil at Ritta). CBG, CBD, and THC concentrations were analyzed in developing flowers harvested at weekly intervals beginning 2 weeks after flowering until crop maturity. Location and planting date had some effect on cannabinoids profile, bu...

Agrosystems, Geosciences & Environment

Agronomy

Hemp production has been permitted as a new agricultural commodity in Florida and may serve as a ... more Hemp production has been permitted as a new agricultural commodity in Florida and may serve as a potential rotational crop. Field trials were conducted in the Everglades Agricultural Region with multiple varieties planted at different dates. Data were collected on plant growth parameters, final biomass at harvest, and temporal cannabidiol (CBD) and Δ-9-tetrahydrocannabinol (THC) content in developing flowers. Results showed that at the United States Sugar Corporation (USSC) location, the BaOX variety had higher biomass compared to other varieties and at Everglades Research and Education Center (EREC), varieties ACDC and Cherry wine recorded the highest biomass compared to other varieties. Moreover, plant growth parameters such as plant height, canopy cover and SPAD were significantly affected by variety and planting date. Total CBD and THC content in plants increased over time for most varieties except for Early bird and Cherry abacus under second planting. There was a significantly...

Frontiers in Plant Science

Florida orange trees have been affected by huanglongbing (HLB) for more than a decade. To allevia... more Florida orange trees have been affected by huanglongbing (HLB) for more than a decade. To alleviate disease-caused tree decline, maintain fruit productivity, and reduce disease transmission, enhanced foliar spray programs combining vector control and nutritional supplementation have been applied to healthy and diseased trees. The aim of this research was to discover if the various foliar sprays affect fruit peel oil chemical components. In this study, “Valencia” orange trees, with or without HLB (HLB±), were treated with the grower standard program (control, C) or one of four proprietary enhanced foliar spray programs (N1, N2, N3, and N4) over 16 months. Compared with HLB−, HLB+ samples had lower concentrations of typical peel oil components, including valencene, octanal, and decanal, and were abundant in oxidative/dehydrogenated terpenes, such as carvone and limonene oxide. However, limonene, the dominant component, was not affected by any treatment. Control and three out of four e...

Proceedings of the 13th Conference of the International Organization of Citrus Virologists, Riverside, USA: International Organization of Citrus Virologists, University of California, Riverside, USA, 1996

and California were used to develop models for increase and spread of citrus tristeza virus (CW).... more and California were used to develop models for increase and spread of citrus tristeza virus (CW). In locations where the melon aphid, Aphis gossypii Glover, was the predominant vector, C W progressed from low (-5%) to high (-95%) levels in 8-15 yr. In contrast, where the brown citrus aphid, Toxoptera citricida (Kirkaldy), was predominant, this same increase often occurred in only 2-4 yr. Where the melon aphid was the predominant vector, new infections were diffuse and not closely associated with existing infected trees but rather with trees several tree spaces distant. Where both species coexisted, the brown citrus aphid was the dominant species. In this situation, spread to trees immediately adjacent to existing infections was common which resulted in aggregates of CTV-infected trees along with longer distance spread in some instances. C W infections were generally diffuse or quite aggregated where the melon aphid or the brown citrus aphid was the predominant species, respectively. Thus, aphid species greatly influenced the rate and patterns of CTV epidemics, and their presencetabsence was important to predict how CTV will increase in time and space.

Journal of Citrus Pathology, 2014

Journal of Theoretical Biology, 2020

The Citrus tristeza virus (CTV) is one of the most economically devastating citrus diseases world... more The Citrus tristeza virus (CTV) is one of the most economically devastating citrus diseases worldwide. The spread of CTV in eastern Spain was studied by Gottwald et al. with the goal of determining the spatio-temporal mechanisms of spread. Since the subjects in this study are individual trees, it is natural to think of infections as Bernoulli trials. This approach is difficult however, due to the spatial and temporal dependence of the observations. Consequently, a system of ordinary differential equations (ODE) was used to model the probabilities of infection as well as the spatial and temporal dependence. Given the parameters in the ODE, the probabilities of infection are treated as conditionally independent. Using the conditional independence we then specify the joint likelihood function as a Poisson binomial distribution. For the purpose of model selection and hypothesis testing we, employed accumulated prediction error (APE) which has connections to both Bayesian and frequentist frameworks. We demonstrated the robustness of our method in accounting for spatio-temporal dependencies in the data by accurately predicting the spatial distribution of the disease through Join Counts.

LWT - Food Science and Technology, 2015

Plant Disease, 2006

Ammi majus L., a member of the Apiaceae and also known as large bullwort, false Queen Anne's ... more Ammi majus L., a member of the Apiaceae and also known as large bullwort, false Queen Anne's lace, or bishop's-weed, is frequently used in the floral trade to add a lacey look to floral bouquets. A. majus is native to the Mediterranean Region but it is cultivated in major growing areas including Holland, Israel, the United Kingdom, and the United States. During March 2005, virus-like symptoms including mosaic, generalized chlorosis, vein clearing, interveinal chlorosis, and leaf rugosity were observed in nearly all field-grown A. majus plants at two locations in Martin County, Florida. Inclusion body morphology suggested the presence of one or more potyviruses in the symptomatic plants. Potyvirus infection was confirmed in 11 symptomatic plants using a commercially available enzyme-linked immunosorbent assay (ELISA) kit (Agdia, Elkhart, IN). Nucleotide and deduced amino acid sequences of a 1,625-bp region of one of the reverse transcription-polymerase chain reaction products...

European Journal of Plant Pathology, 2014