The sweet potato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the compl... more The sweet potato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the complex of viruses it transmits are major limiting factors to squash production in the southeastern United States. At this time, insecticides are extensively relied upon for the management of whiteflies and, indirectly, whitefly-transmitted viruses. The development of a multi-faceted, integrated pest management (IPM) program is needed to increase the sustainability and profitability of squash production. Experiments in 2018 and 2019 evaluated the effects of insect exclusion netting (IEN) in combination with selected pesticides on whitefly population dynamics and virus incidence in greenhouse-grown squash seedlings. Field experiments from 2018 to 2021 evaluated the effects of mulch type (UV-reflective mulch, live mulch, and white plastic mulch), row covers, and insecticides on whitefly population dynamics, silver leaf disorder (SSL) intensity, virus symptom severity, and marketable yield. IEN ...
Xanthomonas fragariae causes angular leaf spot of strawberry, an important disease in strawberry ... more Xanthomonas fragariae causes angular leaf spot of strawberry, an important disease in strawberry growing regions worldwide. To better understand how X. fragariae multiplies and moves in strawberry plants, a green fluorescent protein (GFP)-labeled strain was constructed and used to monitor the pathogen’s presence in leaf, petiole, and crown tissue with fluorescence microscopy following natural and wound inoculation in three strawberry cultivars. Taqman PCR was used to quantify bacterial densities in these same tissues regardless of the presence of GFP signal. Results showed X. fragariae colonized leaf mesophyll, the top 1 cm portion of the petiole adjacent to the leaf blade, and was occasionally found colonizing xylem vessels down to the middle of the petioles. The colonization of vascular bundles and the limited systemic movement that was observed appeared to be a passive process, of which the frequency increased with wounding and direct infiltration of bacteria into leaf veins. X. ...
Xanthomonas fragariae, the bacterium causing angular leaf spot (ALS) of strawberry, is found rout... more Xanthomonas fragariae, the bacterium causing angular leaf spot (ALS) of strawberry, is found routinely on strawberry nursery stock. Although ALS can be a serious disease in production fields, it can be particularly problematic in the sale and trade of commercial nursery stock because of international trade regulations. Heat treatment has been shown to be an effective treatment for managing ALS on nursery stock in small-scale experimental trials. The objective of this research was to design, build, and trial precision thermotherapy units for managing ALS for both research and commercial applications and to test a new thermotherapeutic protocol on strawberry nursery stock that combines a conditioning thermal treatment with an eradicative thermal treatment. Small-plot trials were conducted to evaluate the efficacy of precision thermotherapy on control of ALS using known sources of infected nursery stock. Additionally, trials were conducted in cooperation with commercial nurseries to de...
Authors describe performance of Tospovirus-resistant tomato varieties under commercial production... more Authors describe performance of Tospovirus-resistant tomato varieties under commercial production settings in Dade County, FL. Virus resistance has become important for this area since the emergence of two new tomato-infecting tospoviruses. Knowledge of availability and performance of resistant varieties will help growers who are looking for alternative varieties.
Leaf spot, leaf blight, and leaf scorch are foliar diseases of strawberry found commonly in peren... more Leaf spot, leaf blight, and leaf scorch are foliar diseases of strawberry found commonly in perennial plantings throughout North America. The effect of these diseases on strawberry production is suspected to range from reduced yields to shortened production life. A three-year study was implemented to determine to what extent these diseases impact yield and the production life of a planting, and to define when it is economically feasible to manage these diseases. The second year of the study focused on: 1) Gathering return yield, crown count, biomass, pre- and post-renovation foliar disease data in an established ‘Jewel’ plot in Ithaca, NY; 2) Gathering baseline yield data, crown count, biomass, pre- and post-renovation foliar disease data in new ‘Kent’ and ‘Jewel’ plots in Geneva, NY; and 3) Continuing to refine experimental procedures to look at the effects of disease under experimental conditions. The harvest from the ‘Jewel’ planting in Ithaca was the first in which return yield ...
Squash vein yellowing virus (SqVYV) is the cause of viral watermelon vine decline. The virus is w... more Squash vein yellowing virus (SqVYV) is the cause of viral watermelon vine decline. The virus is whitefly-transmitted, induces a systemic wilt of watermelon plants, and causes necrosis and discoloration of the fruit rind. In the field, SqVYV is often detected in watermelon in mixed infections with other viruses including the aphid-transmitted Papaya ringspot virus type W (PRSV-W). In this study, watermelon plants of different ages were inoculated with SqVYV or SqVYV+PRSV-W in the greenhouse or SqVYV in the field to characterize the physiological response to infection. Symptoms of vine decline appeared about 12 to 16 days after inoculation with SqVYV regardless of plant age at time of inoculation, plant growth habit (trellised or nontrellised), and location (greenhouse or field). However, the presence of PRSV-W delayed the appearance of vine decline symptoms by 2 to 4 days, and vine decline did not develop on plants with no fruit. For all inoculation treatments, more severe symptoms w...
Xanthomonas fragariae is a bacterium that causes angular leaf spot of strawberry. Asymptomatic in... more Xanthomonas fragariae is a bacterium that causes angular leaf spot of strawberry. Asymptomatic infection is common and contributes to the difficulties in disease management. The aim of this study was to develop a loop-mediated isothermal amplification (LAMP) assay as an efficient method for detection of asymptomatic infections of X. fragariae. In addition, a new method of sample preparation was developed that allows sampling of a larger amount of plant tissue, hence increasing the detection rate in real-life samples. The sample preparation procedure includes an overnight incubation of strawberry tissues in phosphate-buffered saline (PBS), followed by a quick sample concentration and a boiling step to extract DNA for amplification. The detection limit of the LAMP assay was approximately 2×10 3 CFU/mL for pure bacteria culture and 300 CFU/mL for bacteria spiked strawberry leaf and petiole samples. LAMP provided a 2-3 fold lower detection limit than the standard qPCR assay but was faster, and more user-friendly. The LAMP assay should serve as a rapid, sensitive and cost-effective tool for detecting asymptomatic infections of X. fragariae in strawberry nursery stock and contribute to improved disease management.
Xanthomonas fragariae is the causal agent of angular leaf spot of strawberry. Short-read sequence... more Xanthomonas fragariae is the causal agent of angular leaf spot of strawberry. Short-read sequences were generated for two X. fragariae strains with different virulence phenotypes on the Illumina HiSeq 2000 platform. The genome sequences will contribute to a better understanding of pathogen evolution and the genes contributing to virulence in X. fragariae. ABSTRACT Xanthomonas fragariae is the causal agent of angular leaf spot of strawberry. Short-read sequences were generated for two X. fragariae strains with different virulence phenotypes on the Illumina HiSeq 2000 platform. These genome sequences will contribute to a better understanding of pathogen evolution and the genes contributing to virulence in X. fragariae.
In California, angular leaf spot (ALS) is a common disease in strawberry nursery production, and ... more In California, angular leaf spot (ALS) is a common disease in strawberry nursery production, and a major concern for nurseries wishing to export plants. As the spatial pattern of a disease can offer insight into pathogen source, mode of dissemination, and how current crop management practices affect epidemic development, an understanding of the spatial pattern of ALS would allow nursery growers to make informed decisions regarding disease management. Ninety-seven field assessments of disease incidence were performed at different nursery locations in 2014 and 2015 to quantify ALS spatial pattern under commercial conditions. Both point-pattern and geostatistical statistical procedures were used to analyze the data. The spatial pattern of ALS was characterized by a high degree of heterogeneity, as indicated by high median values of the beta-binomial distribution’s theta parameter (0.643), and the index of dispersion, D (4.218). The binary power law provided a robust description of the ...
Agrobacterium larrymoorei causes tumors on weeping fig. The association between propagation and p... more Agrobacterium larrymoorei causes tumors on weeping fig. The association between propagation and pathogen spread in mother trees and daughter branches was studied in a commercial nursery. The mother tree planting was scouted for tumors prior to and after propagation. Branches selected for propagation were tagged to track disease development. The spatial distribution of crown gall in the mother tree planting was characterized with runs, join-count, and spatial autocorrelation analyses. The association of disease in mother trees and daughter branches was characterized with cross-correlation analysis. The incidence of crown gall in the mother tree planting increased from 7% prior to propagation to 32% eight months after propagation. Of the 4193 daughter branches monitored, 3.8% developed tumors. Runs analysis indicated significant clustering of diseased mother trees. Significant cross-correlations between mother trees and daughter branches with symptoms of crown gall were detected out t...
The binary power law (BPL) has been successfully used to characterize heterogeneity (overdispersi... more The binary power law (BPL) has been successfully used to characterize heterogeneity (overdispersion or small-scale aggregation) of disease incidence for many plant pathosystems. With the BPL, the log of the observed variance is a linear function of the log of the theoretical variance for a binomial distribution over the range of incidence values, and the estimated scale (κ) and slope (b) parameters provide information on the characteristics of aggregation. When b = 1, the interpretation is that the degree of aggregation remains constant over the range of incidence values observed; otherwise, aggregation is variable. In two articles published in this journal in 2009, Gosme and Lucas used their stochastic simulation model, Cascade, to show a multiphasic (split-line) relationship of the variances, with straight-line (linear) relationships on a log-log scale within each phase. In particular, they showed a strong break point in the lines at very low incidence, with b considerably >1 in the first line segment (corresponding to a range of incidence values usually not
Butternut squash (Cucurbita moschata) is an important vegetable crop grown and consumed in most s... more Butternut squash (Cucurbita moschata) is an important vegetable crop grown and consumed in most states in the United States. C. moschata lines and interspecific hybrids between Cucurbita species are also used as rootstocks for grafting watermelon and melon. However, currently most commercially available C. moschata squash varieties are highly susceptible to crown and root rot caused by the oomycete pathogen Phytophthora capsici, especially in the southeastern United States. All available plant introductions (PIs) of C. moschata (319 PIs) were evaluated for resistance to crown rot. Four-week-old plants were inoculated with 104 zoospores from a local South Carolina isolate of P. capsici. Plants were rated for disease severity 3 weeks after inoculation using a 0 to 5 rating scale (0 = no symptoms and 5 = plant dead). The majority (87%) of the C. moschata PIs were highly susceptible to crown rot in the first evaluation and were rated as 5. Reevaluation of the promising PIs identified se...
The whitefly, Bemisia tabaci MEAM1 Gennadius causes serious losses to Florida vegetable and ornam... more The whitefly, Bemisia tabaci MEAM1 Gennadius causes serious losses to Florida vegetable and ornamental production. In 2019, a maximum dose bioassay was administered to 20 field populations of B. tabaci MEAM1 collected from various economic and weed hosts across south Florida to assess insecticide efficacy. The maximum dose bioassay tests the top labeled rate of the insecticide against B. tabaci adults on treated cotton leaves in a Petri dish over a 72-h period. A susceptible laboratory colony of B. tabaci MEAM1 and a colony of B. tabaci MED were also tested. Survival over 72 h was used to produce an area under the maximum dose curve, which was used to compare insecticide effects on different populations. Overall, imidacloprid demonstrated the poorest efficacy, dinotefuran and flupyradifurone were the most effective, and bifenthrin, cyantraniliprole, and thiamethoxam tended to group together, providing intermediate control. Across populations tested, survival in whitefly adults treat...
Heat treatment has been shown to be an effective method for reducing systemic pathogens in strawb... more Heat treatment has been shown to be an effective method for reducing systemic pathogens in strawberry but the process often has adverse effects on plant health. Research has shown that a brief heat treatment of plants at a lower temperature prior to the main heat treatment can induce heat shock proteins, which serve to protect the plant from damage when treated at higher temperatures. The objective of this study was to determine the relative gene expression of two heat shock factors (HSFs) and eight heat shock proteins (HSPs) in two strawberry cultivars (Festival and Ventana) known to have differential tolerance to heat. Strawberry plants were treated at 37°C for 1 hour to induce the heat shock response. Total RNA was extracted and reverse transcription polymerase chain reaction (RT-PCR) was used to determine the amount of target produced. Relative gene expression was determined using the 2 −ΔΔct method. Results showed that transcripts of one HSF and five HSPs were significantly more abundant in cv. Festival (p < 0.05) but transcripts from only one gene, sHsp15.96, were significantly more abundant in cv. Ventana. Results of this study have identified gene candidates that may confer heat tolerance in strawberry, which may be useful for selecting heat tolerant plants in breeding programs.
Epidemics of tomato yellow leaf curl virus (TYLCV; species Tomato yellow leaf curl begomovirus) h... more Epidemics of tomato yellow leaf curl virus (TYLCV; species Tomato yellow leaf curl begomovirus) have been problematic to tomato production in the southeastern United States since the first detection of the virus in Florida in the late 1990s. Current strategies for management focus on farm-centric tactics that have had limited success for controlling either TYLCV or its whitefly vector. Areawide pest management (AWPM)—loosely defined as a coordinated effort to implement management strategies on a regional scale—may be a viable management alternative. A prerequisite for development of an AWPM program is an understanding of the spatial and temporal dynamics of the target pathogen and pest populations. The objective of this study was to characterize populations of whitefly and TYLCV in commercial tomato production fields in southwestern Florida and utilize this information to develop predictors of whitefly density and TYLCV disease incidence as a function of environmental and geographic...
The sweet potato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the compl... more The sweet potato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the complex of viruses it transmits are major limiting factors to squash production in the southeastern United States. At this time, insecticides are extensively relied upon for the management of whiteflies and, indirectly, whitefly-transmitted viruses. The development of a multi-faceted, integrated pest management (IPM) program is needed to increase the sustainability and profitability of squash production. Experiments in 2018 and 2019 evaluated the effects of insect exclusion netting (IEN) in combination with selected pesticides on whitefly population dynamics and virus incidence in greenhouse-grown squash seedlings. Field experiments from 2018 to 2021 evaluated the effects of mulch type (UV-reflective mulch, live mulch, and white plastic mulch), row covers, and insecticides on whitefly population dynamics, silver leaf disorder (SSL) intensity, virus symptom severity, and marketable yield. IEN ...
Xanthomonas fragariae causes angular leaf spot of strawberry, an important disease in strawberry ... more Xanthomonas fragariae causes angular leaf spot of strawberry, an important disease in strawberry growing regions worldwide. To better understand how X. fragariae multiplies and moves in strawberry plants, a green fluorescent protein (GFP)-labeled strain was constructed and used to monitor the pathogen’s presence in leaf, petiole, and crown tissue with fluorescence microscopy following natural and wound inoculation in three strawberry cultivars. Taqman PCR was used to quantify bacterial densities in these same tissues regardless of the presence of GFP signal. Results showed X. fragariae colonized leaf mesophyll, the top 1 cm portion of the petiole adjacent to the leaf blade, and was occasionally found colonizing xylem vessels down to the middle of the petioles. The colonization of vascular bundles and the limited systemic movement that was observed appeared to be a passive process, of which the frequency increased with wounding and direct infiltration of bacteria into leaf veins. X. ...
Xanthomonas fragariae, the bacterium causing angular leaf spot (ALS) of strawberry, is found rout... more Xanthomonas fragariae, the bacterium causing angular leaf spot (ALS) of strawberry, is found routinely on strawberry nursery stock. Although ALS can be a serious disease in production fields, it can be particularly problematic in the sale and trade of commercial nursery stock because of international trade regulations. Heat treatment has been shown to be an effective treatment for managing ALS on nursery stock in small-scale experimental trials. The objective of this research was to design, build, and trial precision thermotherapy units for managing ALS for both research and commercial applications and to test a new thermotherapeutic protocol on strawberry nursery stock that combines a conditioning thermal treatment with an eradicative thermal treatment. Small-plot trials were conducted to evaluate the efficacy of precision thermotherapy on control of ALS using known sources of infected nursery stock. Additionally, trials were conducted in cooperation with commercial nurseries to de...
Authors describe performance of Tospovirus-resistant tomato varieties under commercial production... more Authors describe performance of Tospovirus-resistant tomato varieties under commercial production settings in Dade County, FL. Virus resistance has become important for this area since the emergence of two new tomato-infecting tospoviruses. Knowledge of availability and performance of resistant varieties will help growers who are looking for alternative varieties.
Leaf spot, leaf blight, and leaf scorch are foliar diseases of strawberry found commonly in peren... more Leaf spot, leaf blight, and leaf scorch are foliar diseases of strawberry found commonly in perennial plantings throughout North America. The effect of these diseases on strawberry production is suspected to range from reduced yields to shortened production life. A three-year study was implemented to determine to what extent these diseases impact yield and the production life of a planting, and to define when it is economically feasible to manage these diseases. The second year of the study focused on: 1) Gathering return yield, crown count, biomass, pre- and post-renovation foliar disease data in an established ‘Jewel’ plot in Ithaca, NY; 2) Gathering baseline yield data, crown count, biomass, pre- and post-renovation foliar disease data in new ‘Kent’ and ‘Jewel’ plots in Geneva, NY; and 3) Continuing to refine experimental procedures to look at the effects of disease under experimental conditions. The harvest from the ‘Jewel’ planting in Ithaca was the first in which return yield ...
Squash vein yellowing virus (SqVYV) is the cause of viral watermelon vine decline. The virus is w... more Squash vein yellowing virus (SqVYV) is the cause of viral watermelon vine decline. The virus is whitefly-transmitted, induces a systemic wilt of watermelon plants, and causes necrosis and discoloration of the fruit rind. In the field, SqVYV is often detected in watermelon in mixed infections with other viruses including the aphid-transmitted Papaya ringspot virus type W (PRSV-W). In this study, watermelon plants of different ages were inoculated with SqVYV or SqVYV+PRSV-W in the greenhouse or SqVYV in the field to characterize the physiological response to infection. Symptoms of vine decline appeared about 12 to 16 days after inoculation with SqVYV regardless of plant age at time of inoculation, plant growth habit (trellised or nontrellised), and location (greenhouse or field). However, the presence of PRSV-W delayed the appearance of vine decline symptoms by 2 to 4 days, and vine decline did not develop on plants with no fruit. For all inoculation treatments, more severe symptoms w...
Xanthomonas fragariae is a bacterium that causes angular leaf spot of strawberry. Asymptomatic in... more Xanthomonas fragariae is a bacterium that causes angular leaf spot of strawberry. Asymptomatic infection is common and contributes to the difficulties in disease management. The aim of this study was to develop a loop-mediated isothermal amplification (LAMP) assay as an efficient method for detection of asymptomatic infections of X. fragariae. In addition, a new method of sample preparation was developed that allows sampling of a larger amount of plant tissue, hence increasing the detection rate in real-life samples. The sample preparation procedure includes an overnight incubation of strawberry tissues in phosphate-buffered saline (PBS), followed by a quick sample concentration and a boiling step to extract DNA for amplification. The detection limit of the LAMP assay was approximately 2×10 3 CFU/mL for pure bacteria culture and 300 CFU/mL for bacteria spiked strawberry leaf and petiole samples. LAMP provided a 2-3 fold lower detection limit than the standard qPCR assay but was faster, and more user-friendly. The LAMP assay should serve as a rapid, sensitive and cost-effective tool for detecting asymptomatic infections of X. fragariae in strawberry nursery stock and contribute to improved disease management.
Xanthomonas fragariae is the causal agent of angular leaf spot of strawberry. Short-read sequence... more Xanthomonas fragariae is the causal agent of angular leaf spot of strawberry. Short-read sequences were generated for two X. fragariae strains with different virulence phenotypes on the Illumina HiSeq 2000 platform. The genome sequences will contribute to a better understanding of pathogen evolution and the genes contributing to virulence in X. fragariae. ABSTRACT Xanthomonas fragariae is the causal agent of angular leaf spot of strawberry. Short-read sequences were generated for two X. fragariae strains with different virulence phenotypes on the Illumina HiSeq 2000 platform. These genome sequences will contribute to a better understanding of pathogen evolution and the genes contributing to virulence in X. fragariae.
In California, angular leaf spot (ALS) is a common disease in strawberry nursery production, and ... more In California, angular leaf spot (ALS) is a common disease in strawberry nursery production, and a major concern for nurseries wishing to export plants. As the spatial pattern of a disease can offer insight into pathogen source, mode of dissemination, and how current crop management practices affect epidemic development, an understanding of the spatial pattern of ALS would allow nursery growers to make informed decisions regarding disease management. Ninety-seven field assessments of disease incidence were performed at different nursery locations in 2014 and 2015 to quantify ALS spatial pattern under commercial conditions. Both point-pattern and geostatistical statistical procedures were used to analyze the data. The spatial pattern of ALS was characterized by a high degree of heterogeneity, as indicated by high median values of the beta-binomial distribution’s theta parameter (0.643), and the index of dispersion, D (4.218). The binary power law provided a robust description of the ...
Agrobacterium larrymoorei causes tumors on weeping fig. The association between propagation and p... more Agrobacterium larrymoorei causes tumors on weeping fig. The association between propagation and pathogen spread in mother trees and daughter branches was studied in a commercial nursery. The mother tree planting was scouted for tumors prior to and after propagation. Branches selected for propagation were tagged to track disease development. The spatial distribution of crown gall in the mother tree planting was characterized with runs, join-count, and spatial autocorrelation analyses. The association of disease in mother trees and daughter branches was characterized with cross-correlation analysis. The incidence of crown gall in the mother tree planting increased from 7% prior to propagation to 32% eight months after propagation. Of the 4193 daughter branches monitored, 3.8% developed tumors. Runs analysis indicated significant clustering of diseased mother trees. Significant cross-correlations between mother trees and daughter branches with symptoms of crown gall were detected out t...
The binary power law (BPL) has been successfully used to characterize heterogeneity (overdispersi... more The binary power law (BPL) has been successfully used to characterize heterogeneity (overdispersion or small-scale aggregation) of disease incidence for many plant pathosystems. With the BPL, the log of the observed variance is a linear function of the log of the theoretical variance for a binomial distribution over the range of incidence values, and the estimated scale (κ) and slope (b) parameters provide information on the characteristics of aggregation. When b = 1, the interpretation is that the degree of aggregation remains constant over the range of incidence values observed; otherwise, aggregation is variable. In two articles published in this journal in 2009, Gosme and Lucas used their stochastic simulation model, Cascade, to show a multiphasic (split-line) relationship of the variances, with straight-line (linear) relationships on a log-log scale within each phase. In particular, they showed a strong break point in the lines at very low incidence, with b considerably >1 in the first line segment (corresponding to a range of incidence values usually not
Butternut squash (Cucurbita moschata) is an important vegetable crop grown and consumed in most s... more Butternut squash (Cucurbita moschata) is an important vegetable crop grown and consumed in most states in the United States. C. moschata lines and interspecific hybrids between Cucurbita species are also used as rootstocks for grafting watermelon and melon. However, currently most commercially available C. moschata squash varieties are highly susceptible to crown and root rot caused by the oomycete pathogen Phytophthora capsici, especially in the southeastern United States. All available plant introductions (PIs) of C. moschata (319 PIs) were evaluated for resistance to crown rot. Four-week-old plants were inoculated with 104 zoospores from a local South Carolina isolate of P. capsici. Plants were rated for disease severity 3 weeks after inoculation using a 0 to 5 rating scale (0 = no symptoms and 5 = plant dead). The majority (87%) of the C. moschata PIs were highly susceptible to crown rot in the first evaluation and were rated as 5. Reevaluation of the promising PIs identified se...
The whitefly, Bemisia tabaci MEAM1 Gennadius causes serious losses to Florida vegetable and ornam... more The whitefly, Bemisia tabaci MEAM1 Gennadius causes serious losses to Florida vegetable and ornamental production. In 2019, a maximum dose bioassay was administered to 20 field populations of B. tabaci MEAM1 collected from various economic and weed hosts across south Florida to assess insecticide efficacy. The maximum dose bioassay tests the top labeled rate of the insecticide against B. tabaci adults on treated cotton leaves in a Petri dish over a 72-h period. A susceptible laboratory colony of B. tabaci MEAM1 and a colony of B. tabaci MED were also tested. Survival over 72 h was used to produce an area under the maximum dose curve, which was used to compare insecticide effects on different populations. Overall, imidacloprid demonstrated the poorest efficacy, dinotefuran and flupyradifurone were the most effective, and bifenthrin, cyantraniliprole, and thiamethoxam tended to group together, providing intermediate control. Across populations tested, survival in whitefly adults treat...
Heat treatment has been shown to be an effective method for reducing systemic pathogens in strawb... more Heat treatment has been shown to be an effective method for reducing systemic pathogens in strawberry but the process often has adverse effects on plant health. Research has shown that a brief heat treatment of plants at a lower temperature prior to the main heat treatment can induce heat shock proteins, which serve to protect the plant from damage when treated at higher temperatures. The objective of this study was to determine the relative gene expression of two heat shock factors (HSFs) and eight heat shock proteins (HSPs) in two strawberry cultivars (Festival and Ventana) known to have differential tolerance to heat. Strawberry plants were treated at 37°C for 1 hour to induce the heat shock response. Total RNA was extracted and reverse transcription polymerase chain reaction (RT-PCR) was used to determine the amount of target produced. Relative gene expression was determined using the 2 −ΔΔct method. Results showed that transcripts of one HSF and five HSPs were significantly more abundant in cv. Festival (p < 0.05) but transcripts from only one gene, sHsp15.96, were significantly more abundant in cv. Ventana. Results of this study have identified gene candidates that may confer heat tolerance in strawberry, which may be useful for selecting heat tolerant plants in breeding programs.
Epidemics of tomato yellow leaf curl virus (TYLCV; species Tomato yellow leaf curl begomovirus) h... more Epidemics of tomato yellow leaf curl virus (TYLCV; species Tomato yellow leaf curl begomovirus) have been problematic to tomato production in the southeastern United States since the first detection of the virus in Florida in the late 1990s. Current strategies for management focus on farm-centric tactics that have had limited success for controlling either TYLCV or its whitefly vector. Areawide pest management (AWPM)—loosely defined as a coordinated effort to implement management strategies on a regional scale—may be a viable management alternative. A prerequisite for development of an AWPM program is an understanding of the spatial and temporal dynamics of the target pathogen and pest populations. The objective of this study was to characterize populations of whitefly and TYLCV in commercial tomato production fields in southwestern Florida and utilize this information to develop predictors of whitefly density and TYLCV disease incidence as a function of environmental and geographic...
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Papers by William Turechek