Xylella Fastidiosa

Xylella fastidiosa is a harmful bacterial pathogen affecting a variety of plants, causing significant economic losses in agriculture. In Alabama, the pathogen’s presence has been steadily increasing, impacting fruit crops like blueberries, grapes, and peaches. This blog post delves into the research findings on Xylella fastidiosa in Alabama, highlighting the diseases it causes, its primary insect vectors, and essential strategies for managing its spread.

 

Xylella Fastidiosa in Alabama: A Growing Concern for Agriculture

Xylella fastidiosa, responsible for a range of plant diseases, has been identified as a significant threat to crops across Alabama. Research conducted in various agricultural regions of Alabama, including the Gulf Coast, Central, and North Alabama, has confirmed the presence of the pathogen in key fruit crops such as blueberries, grapes, peaches, and plums.

The pathogen is transmitted by sharpshooter insects, which feed on the xylem of plants, allowing the bacteria to spread from one plant to another. Xylella fastidiosa causes several plant diseases, including bacterial leaf scorch, Pierce's disease, and phoney peach disease. These diseases result in symptoms such as leaf necrosis, stunted growth, premature leaf drop, and reduced fruit production. The impact of these diseases on Alabama's agriculture cannot be overstated, as they affect both the health of crops and the state's agricultural economy.

 

Key Research Findings on Xylella Fastidiosa in Alabama

Study 1: Rabbiteye Blueberry Cultivation in Alabama

A study conducted at Auburn University investigated the performance of various rabbiteye blueberry cultivars in North Alabama, focusing on disease resistance and the presence of pathogens such as Xylella fastidiosa. The research highlighted that blueberries are particularly susceptible to bacterial leaf scorch, a condition caused by Xylella fastidiosa. The disease leads to premature leaf drop, which reduces the plant’s ability to photosynthesize and negatively impacts fruit yield. The study emphasized the importance of selecting disease-resistant blueberry cultivars to mitigate the spread of Xylella in the region.

Study 2: Sharpshooter Leafhopper Abundance and Distribution in Alabama

A study on the seasonal abundance of sharpshooter leafhoppers across Alabama revealed that these insects are the primary vectors of Xylella fastidiosa. The study found that Homalodisca vitripennis (glassy-winged sharpshooter) and Graphocephala versuta (blue-green sharpshooter) are the most common sharpshooters in Alabama, with the highest populations found in the Gulf Coast region. These sharpshooters feed on plant xylem, transmitting Xylella fastidiosa to healthy plants, facilitating the spread of bacterial diseases in orchards and vineyards .

Study 3: Spread of Xylella Fastidiosa in Alabama’s Orchards and Vineyards

A comprehensive study in Alabama’s orchards and vineyards confirmed the widespread presence of Xylella fastidiosa across several fruit crops. The study showed that Xylella infection caused significant damage to crops such as muscadine grapes, blueberries, peaches, and plums, with symptoms ranging from leaf necrosis to stunted plant growth. Researchers identified various sharpshooter species that contribute to the spread of the bacteria, including Homalodisca vitripennis and Oncometopia orbona, with each species exhibiting different seasonal patterns of abundance. This research underscores the importance of timely monitoring and vector control to reduce the risk of Xylella transmission .

 

Impact of Xylella Fastidiosa on Alabama’s Agriculture

The spread of Xylella fastidiosa in Alabama poses a significant threat to agriculture, particularly in areas with high concentrations of fruit crops. The pathogen affects a wide variety of plants, but its impact on crops like blueberries, muscadine grapes, and peaches is particularly concerning. For instance, bacterial leaf scorch in blueberries leads to premature leaf drop and diminished fruit quality, making the crop less viable for farmers. Similarly, Pierce’s disease in grapes causes vine death, which severely affects grape production.

As Alabama’s agricultural landscape continues to be impacted by this pathogen, managing its spread is crucial for the state’s economy. Integrated pest management (IPM) strategies, including controlling sharpshooter populations and selecting disease-resistant plant cultivars, are essential steps in mitigating the risks posed by Xylella fastidiosa.

 

Strategies for Managing Xylella Fastidiosa in Alabama

To address the growing issue of Xylella fastidiosa in Alabama, researchers recommend a combination of monitoring, pest control, and the use of disease-resistant cultivars. Early detection of the disease is crucial, as it allows farmers to implement control measures before the infection spreads. Regular monitoring of sharpshooter populations using yellow sticky traps is a key strategy to track vector abundance and predict the timing of Xylella transmission.

Additionally, farmers should focus on selecting cultivars that are resistant or tolerant to Xylella infection. For example, certain grape cultivars, such as muscadine grapes, have shown some resistance to Pierce’s disease, though mild symptoms may still occur under high disease pressure. The use of insecticides to control sharpshooter populations can also reduce the risk of Xylella transmission, although the effectiveness of chemical treatments can vary depending on environmental conditions and insect population density.

Table: Summary of Xylella fastidiosa Presence in Alabama

Region	Study Outcome	Impact on Crops	Sharpshooter Vectors
Gulf Coast	High prevalence of Xylella fastidiosa in muscadine grapes, peaches, and blueberries	Significant damage in blueberries, grapes, and citrus	Homalodisca vitripennis (Glassy-winged sharpshooter)
Central Alabama	Moderate infection rates in peaches and grapes	Reduced fruit yield and quality	Graphocephala versuta (Blue-green sharpshooter)
North Alabama	Lower infection rates, but presence in blueberries	Minor symptoms in blueberries and grapes	Homalodisca vitripennis, Oncometopia orbona

Final Thoughts

The spread of Xylella fastidiosa in Alabama is a growing concern that threatens the state’s agricultural crops. Research has confirmed the presence of the pathogen in several fruit crops, with sharpshooter insects playing a key role in its transmission. Through integrated pest management, early detection, and the use of disease-resistant cultivars, farmers in Alabama can take proactive measures to reduce the impact of Xylella fastidiosa on their crops. Continued research and monitoring will be crucial to managing the spread of this pathogen and ensuring the sustainability of Alabama’s agricultural industry.

 

References:

• Ma, X. (2010). The Occurrence of Xylella fastidiosa and Its Sharpshooter Vectors in Selected Alabama Orchards and Vineyards. Master's thesis, Auburn University.
• Ma, X., Coneva, E., Fadamiro, H., Murphy, J. F., Ray, C., & Dane, F. (2010). Seasonal Occurrence and Abundance of Sharpshooter Leafhoppers in Alabama Orchards and Vineyards. International Journal of Fruit Science, 10(3), 341-354. DOI: 10.1080/15538362.2010.510428.
• Potter, R. J. (2010). Performance of Newly Released and Well-Established Rabbiteye Blueberry (Vaccinium ashei) Cultivars in North Alabama. Master's thesis, Auburn University.

Xylella fastidiosa (Xf), a bacterium that threatens various crops, has recently become a subject of growing concern in the Dakota region of the United States. As the Midwest faces changing climate conditions, the presence of this pathogen in nearby states has raised alarms about its potential impact on local agriculture. This blog post delves into the research and findings surrounding Xf in Dakota, detailing its presence, associated plant diseases, and strategies for managing its spread.

Xylella fastidiosa and Its Impact

Xylella fastidiosa is a plant-pathogenic bacterium that causes several destructive diseases in a wide range of crops. It is known to infect plants such as grapevines, almond trees, citrus trees, and even ornamental plants. The pathogen is transmitted primarily by xylem-feeding insects, such as sharpshooter leafhoppers. These insects feed on plant xylem tissue, where the bacterium thrives, blocking the plant’s water transport system. As a result, infected plants exhibit symptoms like leaf scorch, stunted growth, and even death.

The Threat of Xylella fastidiosa to Dakota’s Agriculture

In Dakota, the emergence of Xylella fastidiosa presents a significant challenge to local agriculture, especially in the context of plant diseases that affect crucial crops. The pathogen has the potential to wreak havoc on vineyards, orchards, and other crops susceptible to its effects.

Recent research suggests that Xf may be adapting to the colder climates of the Dakotas, which raises concerns about its spread in the region. While the bacterium has historically been restricted to warmer, subtropical climates, climate change could exacerbate its reach into cooler areas. This is especially concerning for the grape production industry, which is expanding in Dakota.

Research and Presence of Xylella fastidiosa in Dakota

The first signs of Xylella fastidiosa in Dakota were reported in nearby Oklahoma and Nebraska. Recent studies have detected Xf in grapevines in Oklahoma, with the 'Concord' cultivar showing typical symptoms of Pierce's Disease (PD). The pathogen's presence in these regions has sparked concerns about its potential migration to the Dakota region. The cold-tolerant strain of Xf found in mulberry trees in Nebraska further supports the possibility that Xf could thrive in the harsher climates of Dakota.

Several studies indicate that the pathogen may be more adaptable to the Midwest’s fluctuating temperatures than previously thought. The strain found in Nebraska and Massachusetts appears to tolerate the cold better, which means it could potentially spread to Dakota vineyards.

Research Findings

Region	Xylella fastidiosa Presence	Disease Outcome	Impact on Agriculture
Oklahoma	Confirmed	Pierce’s Disease in Concord Grapes	Significant threat to local vineyards
Nebraska	Found in Mulberry Trees	No major damage reported yet	Potential risk for broader crop impact
South Dakota	Not confirmed	N/A	At risk, but no confirmed reports of Xf

Source: Galvez, L.C., K. Korus, J. Fernandez, J.L. Behn, and N. Banjara. 2010. "The Threat of Pierce’s Disease to Midwest Wine and Table Grapes."

Key Factors Contributing to the Spread of Xylella fastidiosa in Dakota

Several factors increase the likelihood of Xf spreading in Dakota:

• Climate Change: Rising temperatures in the Midwest could make the environment more favorable for Xf and its insect vectors. Warmer winters and longer growing seasons may provide an extended window for disease transmission.

• Insect Vectors: While the glassy-winged sharpshooter, a known vector of Xf, is not yet established in Dakota, other related xylem-feeding insects are present in the region. These insects could play a role in spreading Xf if the bacterium is introduced.

• Crop Susceptibility: The region's growing grape industry, along with other crops like almonds and fruit trees, may be vulnerable to the effects of Xf. Researchers have noted that certain cultivars may show varying levels of resistance to Xf, making it important for local farmers to consider resistant varieties.

Strategies for Managing Xylella fastidiosa in Dakota

As the risk of Xylella fastidiosa spreading to Dakota increases, it is crucial to develop effective management strategies. Several approaches used successfully in other regions with Pierce's Disease may be applicable:

1. Monitoring and Early Detection: Vineyard managers should implement regular monitoring programs to detect Xf early. This includes testing plants for the bacterium and looking for symptoms of disease. Early detection can prevent the disease from spreading unchecked.

2. Resistant Varieties: The use of resistant grape cultivars, such as the muscadine grape, may help mitigate the effects of Xf. However, these varieties are not immune, and research into developing more resistant cultivars is ongoing.

3. Insect Control: Controlling the vector population is key in managing Xf. Early applications of insecticides to target the first generation of sharpshooter leafhoppers can help reduce the spread of the bacterium.

4. Cultural Practices: Vineyard management practices that control insect vectors and improve plant health may reduce the likelihood of disease outbreaks. Proper irrigation and pest management are essential in maintaining a healthy vineyard.

The Future of Xylella fastidiosa in Dakota

The presence of Xylella fastidiosa in nearby states like Oklahoma and Nebraska underscores the need for proactive measures to prevent the spread of the pathogen in Dakota. While it has not yet become a significant issue in the region, climate change and the adaptability of the bacterium and its vectors suggest that the threat may increase over time.

Dakota vineyard managers and agricultural experts must remain vigilant in monitoring for Xf, testing for its presence, and implementing strategies to control its spread. By embracing early detection, resistant cultivars, and vector management techniques, the region can protect its growing agricultural industry from this potentially devastating pathogen.

References

Galvez, L.C., K. Korus, J. Fernandez, J.L. Behn, and N. Banjara. 2010. "The Threat of Pierce’s Disease to Midwest Wine and Table Grapes." APSnet Features. DOI: 10.1094/APSFeature-2010-1015.

Xylella fastidiosa is a bacterial pathogen responsible for a wide range of plant diseases. It has made its way into Oklahoma, and that’s something local growers and researchers are taking very seriously. Diseases like Pierce’s Disease in grapes and bacterial leaf scorch in shade trees are linked to this bacterium. Over the last two decades, research in Oklahoma has revealed the growing footprint of this plant killer, and with rising temperatures, the risk is likely to go up.

This post gives you everything you need to know about Xylella fastidiosa in Oklahoma, based on five important studies. From proof of its presence to its economic impact and management strategies, this blog breaks it down in clear, simple terms.

 

 

Xylella fastidiosa (XF) is a bacterial pathogen that blocks the water-conducting tissues (xylem) in plants. This causes a variety of symptoms including leaf scorch, yellowing, stunted growth, and plant death. It's transmitted mainly through insect vectors like sharpshooters and spittlebugs. Once infected, the plant struggles to get water and nutrients, leading to visible stress and damage.

This bacterium causes several diseases, such as:

·         Pierce’s Disease in grapevines

·         Bacterial Leaf Scorch (BLS) in trees like elm, oak, and sycamore

·         Phony Peach Disease in peaches

 

Proof of Presence in Oklahoma

Study 1: Pierce’s Disease in Canadian County

In 2008, Oklahoma grapevines showed signs of Pierce’s Disease for the first time. The infected plants were found in Canadian County, displaying symptoms like leaf yellowing and browning edges. Oklahoma State University researchers ran tests and confirmed Xylella fastidiosa was the culprit. They used real-time PCR and serological (ELISA) tests to confirm the infection.

·         Reference: Smith, D. L., Dominiak-Olson, J., & Sharber, C. D. (2009). Plant Disease, 93(7), 762

Study 2: First Detection in Elm Trees (2004)

Before grapevines, XF was first detected in 2004 in elm trees at the Oklahoma Botanical Gardens in Stillwater. Researchers found the bacterium in a symptomatic elm through PCR testing and DNA sequencing.

·         Reference: Olson, B. R. et al. (2006). Plant Disease, 90(1), 108

Your provided summary confirms: "XF was first detected in elm trees in 2004 and later in grapevines in 2008, marking a confirmed spread in plant hosts across Oklahoma."

 

 

Spread Across Oklahoma

Study 3: Statewide Surveys in 2016-2017

By 2016-2017, Xylella fastidiosa had been found in multiple counties including Atoka, McCurtain, Cleveland, and even a reappearance in Oklahoma County. Surveys showed this wasn’t just a local issue—it was becoming a statewide concern.

·         Sharpshooter insects (like Graphocephala versuta) were identified as major carriers.

·         PCR and ELISA confirmed XF presence in infected vines.

·         Reference: Wallace, Sara Elizabeth. (2018). Detection and Diagnosis of Red Leaf Diseases of Grapes in Oklahoma. Master’s thesis, Oklahoma State University.

Study 4: Insect Vectors and Weedy Hosts

The 2013 study by Lisa M. Overall found that insect vectors and certain plants in vineyards could harbor XF. Sharpshooters like G. versuta and glassy-winged sharpshooters were confirmed as carriers. 2.4% of insects tested were positive.

·         Reference: Overall, L. M. (2013). Doctoral dissertation, Oklahoma State University.

Study 5: Seasonal Insect Spread and Natural Transmission

From 2008 to 2010, researchers confirmed that the insects found in Oklahoma vineyards were not only infected but capable of transmitting XF to healthy plants like ragweed and alfalfa. G. versuta showed the highest infectivity.

·         Reference: Overall, L. M., & Rebek, E. J. (2015). Journal of Economic Entomology

 

 

Summary Table: Spread and Impact in Oklahoma

Study	Year	Location	Host Plant(s)	Insect Vectors	Confirmed XF	Notes
Study 1	2008	Canadian County	Grapevine	N/A	Yes	First grapevine case (Pierce’s Disease)
Study 2	2004	Stillwater	Elm tree	N/A	Yes	First confirmed case in Oklahoma
Study 3	2016–2017	Atoka, McCurtain, Cleveland, OK County	Grapevines	G. versuta, H. vitripennis	Yes	Statewide survey confirmed spread
Study 4	2010–2013	Vineyards and nurseries	Grape, weeds, trees	G. versuta, C. costalis	Yes	Identified insect carriers and plant reservoirs
Study 5	2008–2010	Central OK	Alfalfa, Ragweed	G. versuta, O. orbona	Yes	Confirmed natural transmission

 

Impact on Oklahoma Agriculture

XF’s spread threatens local agriculture in several ways:

·         Grapevines: Oklahoma’s wine industry is still growing, but XF can destroy entire vineyards.

·         Shade Trees: Elms, oaks, and sycamores—used widely in urban landscaping—are vulnerable.

·         Economic Costs: Infected plants must be removed and replaced, and the cost of managing vector insects adds to the burden.

As the climate warms, insect vectors could expand their territory, further increasing the risk.

 

Managing the Spread

What Can Be Done?

·         Insect Control: Monitor and reduce sharpshooter populations during summer.

·         Clean Equipment: Pruning tools can spread the bacteria. Clean them often.

·         Remove Infected Plants: Rogue out visibly infected vines or trees.

·         Resistant Varieties: Some grapes like 'Black Spanish' show better resistance to XF.

·         Monitor and Report: Stay informed and report symptoms to local extension services.

 

Final Thoughts

Xylella fastidiosa is already in Oklahoma and spreading. With multiple studies proving its presence in grapevines, shade trees, and even insect vectors, growers and land managers must stay alert. The good news is, we have the knowledge, research, and tools to fight back. But it starts with awareness and smart action.

 

References

·         Olson, B. R., Dominiak, J., von Broembsen, S., Berg, M., and Bextine, B. R. "First Report of Xylella fastidiosa in Oklahoma." Plant Disease 90, no. 1 (2006): 108. https://doi.org/10.1094/PD-90-0108B.

·         Smith, D. L., Dominiak-Olson, J., and Sharber, C. D. "First Report of Pierce's Disease of Grape Caused by Xylella fastidiosa in Oklahoma." Plant Disease 93, no. 7 (2009): 762. https://doi.org/10.1094/PDIS-93-7-0762B.

·         Wallace, Sara Elizabeth. Detection and Diagnosis of Red Leaf Diseases of Grapes (Vitis spp) in Oklahoma. Master’s thesis, Oklahoma State University, 2018.

·         Overall, Lisa Marie. Incidence of Xylella fastidiosa in Oklahoma, a Survey of Potential Insect Vectors, and Identification of Potential Plant Reservoir Hosts. Doctoral dissertation, Oklahoma State University, 2013.

·         Overall, L. M., and Rebek, E. J. "Seasonal Abundance and Natural Inoculativity of Insect Vectors of Xylella fastidiosa in Oklahoma Tree Nurseries and Vineyards." Journal of Economic Entomology (2015): 1-10. https://doi.org/10.1093/jee/tov261.

 

In recent years, the agricultural landscape in Oregon has faced a growing challenge: the emergence of Xylella fastidiosa, a bacterial pathogen known for causing a range of devastating plant diseases. Once thought to be a threat mostly confined to warmer climates like California or Italy, this pathogen has now appeared in Oregon, prompting serious concern from researchers, farmers, and state agencies.

This blog post provides a comprehensive overview of the presence of Xylella fastidiosa in Oregon, the plant diseases it can cause, and the impact it may have on the state's agriculture. Using verified sources and summaries from multiple studies, we will explore what Xylella fastidiosa means for Oregon's future and what is being done to contain its spread.

 

 

Xylella fastidiosa is a bacterium that lives in the xylem (water-conducting tissue) of plants and causes diseases by blocking water flow, which leads to leaf scorch, stunted growth, and eventual plant death. It can infect over 300 plant species including grapes, almonds, olives, citrus, pears, and ornamental plants.

It spreads mainly through xylem-feeding insects such as sharpshooters and spittlebugs, which makes it hard to control, especially in regions where these insects are active year-round.

 

Confirmed Presence of Xylella fastidiosa in Oregon (Study 1 & 2)

In 2015, Xylella fastidiosa was officially detected in Oregon for the first time, marking a major turning point. According to a report from Capital Press, symptoms of disease appeared at a pear nursery in Hood River County. Initially, the signs were difficult to identify as they resembled drought stress. After updated testing by the Oregon Department of Agriculture (ODA) and Washington State University, the presence of Xylella was confirmed (Perkowski, 2015).

The bacteria were also found at the National Clonal Germplasm Repository in Corvallis, and potentially spread through scion wood to 22 sites across the state. This prompted the ODA to issue a quarantine in nine counties: Hood River, Benton, Linn, Lane, Marion, Jackson, Yamhill, Multnomah, and Washington.

The ODA enforced fines of up to $10,000 for violations. Emergency steps included banning movement of host plants such as:

·         Pear, cherry, plum, and peach trees

·         Oaks and maples

·         Blueberries and caneberries

Infected plants were to be destroyed, and surveys conducted in surrounding areas.

 

Quarantine & Economic Impact

The quarantine wasn't just about plant health—it had economic implications too. Businesses like Fall Creek Farm & Nursery, which export plant materials to Europe, faced shipment delays. The ODA worked with the USDA's Animal and Plant Health Inspection Service (APHIS) to certify pest-free zones to meet international trade requirements.

Oregon's agriculture exports were at risk, as importing countries like those in Europe enforce strict plant health standards. Even a single outbreak can stall trade deals and impact farm income.

 

Risk to Oregon Crops (Study 2)

As Growing Produce highlighted, Xylella's presence in Oregon could hit local crops hard (Eddy, 2015). Key crops at risk include:

·         Wine grapes (similar to Pierce’s Disease outbreaks in California)

·         Pears and apples

·         Blueberries, almonds, and stone fruits

The disease is spread by insects like leafhoppers, blue-green sharpshooters, and spittlebugs, all of which are present in Oregon. With no cure, once a plant is infected, the only option is removal and destruction.

 

Insect Vectors & Climate Change Concerns (Study 3)

According to the Pacific Northwest Pest Management Handbooks (Pscheidt, 2025), while Pierce’s disease caused by Xylella fastidiosa hasn't taken hold in Oregon's grapevines yet, the blue-green sharpshooter is common in areas like:

·         Willamette Valley

·         Columbia Gorge

·         Medford

·         Milton-Freewater

Although the colder winter season has limited Xylella's spread in the past, climate change is warming Oregon's climate and could remove this natural barrier. If winters continue to get milder, these insects might thrive longer and spread the pathogen more widely.

Surveys from 2000 and 2017 didn’t detect Xylella in Oregon vineyards, but the presence of vectors and warming trends suggests the risk is growing.

 

Oregon Quarantines and Preventive Actions (Study 4)

Another section in the Pacific Northwest Pest Management Handbooks specifically discusses Oregon's plant quarantines (Pscheidt, 2023). The report confirms that:

·         Xylella fastidiosa is on Oregon's regulated pathogen list.

·         All imported grape plants must be tested for Xylella.

·         The glassy-winged sharpshooter, a dangerous vector, was found in 2000 near ornamental nurseries.

·         A statewide survey of 291 samples in 2000 found no evidence of Xylella.

Even though the bacteria hasn’t spread widely, these strict policies show the state's serious commitment to preventing an outbreak.

 

Summary Table: Research Findings on Xylella fastidiosa in Oregon

Study Source	Key Finding	Region Impacted	Confirmed Presence	Insect Vectors Mentioned
Capital Press (2015)	Confirmed Xylella in Hood River pear nursery and Corvallis repository	Hood River, Corvallis	Yes	Unknown initially
Growing Produce (2015)	Detailed risk to wine grapes and fruit crops	9 counties under quarantine	Yes	Leafhoppers, blue-green sharpshooters
Pacific NW Handbooks (2025)	Blue-green sharpshooter present; Xylella not yet spreading in grapes	Willamette Valley, Columbia Gorge, Medford, etc.	No	Blue-green sharpshooter
Pacific NW Handbooks (2023)	Xylella not detected in 291 samples; quarantine rules in place	Statewide	No	Glassy-winged sharpshooter

 

What Should Oregon Farmers and Gardeners Do?

Oregon isn’t in the clear yet. Even though Xylella fastidiosa hasn’t become widespread, the 2015 confirmation in pear trees is proof that it can happen.

Here’s what needs to happen moving forward:

·         Farmers and nurseries should report any suspicious symptoms like leaf scorch or unexpected plant decline.

·         Samples should be submitted with leaves and twigs attached.

·         Everyone in the agriculture sector should follow quarantine rules to stop the spread.

Ongoing monitoring of insect populations, especially in areas like the Willamette Valley and Columbia Gorge, will be key. Education and awareness are also crucial.

 

References

·         Eddy, David. "Bacterial Disease Discovered At Oregon Pear Nursery Causes Quarantine." Growing Produce, December 15, 2015. https://www.growingproduce.com/fruits/apples-pears/bacterial-disease-discovered-at-oregon-pear-nursery-causes-quarantine/.

·         Perkowski, Mateusz. "Bacteria Discovery Prompts Oregon Quarantine." Capital Press, December 9, 2015. https://capitalpress.com/author/capitalpressstaff/.

·         Pscheidt, Jay W. "Grape (Vitis spp.)-Pierce's Disease." Pacific Northwest Pest Management Handbooks, Oregon State University, March 2025. https://pnwhandbooks.org/plantdisease/host-disease/grape-vitis-spp-pierces-disease.

·         Pscheidt, Jay W. "Oregon Quarantines." Pacific Northwest Pest Management Handbooks, March 2023. https://pnwhandbooks.org/plantdisease/pathogen-articles/common/oregons-most-unwanted-invasive-species/oregon-quarantines.