Differential Adaptation Has Resulted in Aggressiveness Variation of on Hosts , , and .

() infects (boxwood), (pachysandra), and spp. (sweet box); yet, how it adapts to its hosts has been unclear. Here, we performed serial passage experiments with the three hosts and measured changes in three aggressiveness components: infectibility, lesion size, and conidial production.

Whole Genome Sequencing-Based Tracing of a 2022 Introduction and Outbreak of pv. .

Globalization has made agricultural commodities more accessible, available, and affordable. However, their global movement increases the potential for invasion by pathogens and necessitates development and implementation of sensitive, rapid, and scalable surveillance methods. Here, we used 35 strains, isolated by multiple diagnostic laboratories, as a case study for using whole genome sequence data in a plant disease diagnostic setting.

The Impatiens Downy Mildew Epidemic in the United States Is Caused by New, Introgressed Lineages of with Prominent Genotypic Diversity and High Evolutionary Potential.

Impatiens downy mildew (IDM) caused by is currently the primary constraint on the production and use of impatiens () as bedding plants worldwide. Downy mildew has been documented since the 1880s from wild-grown spp. but epidemic outbreaks of the disease affecting the commercially grown, ornamental were only reported for the first time in 2003 in the United Kingdom and in 2004 in the United States.

First Report of Dickeya dianthicola causing blackleg on New Guinea Impatiens (Impatiens hawkeri) in New York State, USA.

New Guinea impatiens (NGI), Impatiens hawkeri, has a $54-million wholesale market value in the United States (National Agricultural Statistics Service, 2019) and is highly resistant to Impatiens downy mildew (Plasmopara obducens) according to growers' experience (Warfield, 2011). In March 2019, NGI cv. Petticoat White in a New York greenhouse showed wilting, black stem streaks and vascular discoloration, with a 20% disease incidence.

One Clonal Lineage of Is Primarily Responsible for the Boxwood Blight Epidemic in the United States.

Boxwood blight caused by and is destroying cultivated and native boxwood worldwide, with profound negative economic impacts on the horticulture industry. First documented in the United States in 2011, the disease has now occurred in 30 states. Previous research showed that global populations prior to 2014 had a clonal structure, and only the idiomorph was observed.

Species Show Quantitative and Qualitative Resistance to a Population of Powdery Mildew Isolates from the Eastern United States.

Ornamental plants in the genus are extensively planted in landscapes and home gardens around the world. A major limitation to a more widespread use of these plants is their susceptibility to powdery mildew (PM). In this study, we used multilocus sequence typing (MLST) analysis to gain insights into the population diversity of 32 PM pathogen ( and sp.

Boxwood Blight: Threat to Ornamentals.

Boxwood blight, caused by and , has had devastating effects in gardens since its first appearance in the United Kingdom in 1994. The disease affects two other plants in the Buxaceae: sweet box ( spp.) and pachysandra ( spp.

Emergence of Groundnut ringspot virus and Tomato chlorotic spot virus in Vegetables in Florida and the Southeastern United States.

Groundnut ringspot virus (GRSV) and Tomato chlorotic spot virus (TCSV) are two emerging tospoviruses in Florida. In a survey of the southeastern United States, GRSV and TCSV were frequently detected in solanaceous crops and weeds with tospovirus-like symptoms in south Florida, and occurred sympatrically with Tomato spotted wilt virus (TSWV) in tomato and pepper in south Florida. TSWV was the only tospovirus detected in other survey locations, with the exceptions of GRSV from tomato (Solanum lycopersicum) in South Carolina and New York, both of which are first reports.

Transstadial transmission of Pythium in Bradysia impatiens and lack of adult vectoring capacity.

Fungus gnats have been shown to transmit a variety of plant-pathogenic fungi that produce aerial dispersal stages. However, few studies have examined potential interactions between fungus gnats and oomycetes, including Pythium spp. A series of laboratory experiments were conducted to determine whether fungus gnat adults are vectors of several common greenhouse Pythium spp.

Oidium longipes, A New Powdery Mildew Fungus on Petunia in the USA: A Potential Threat to Ornamental and Vegetable Solanaceous Crops.

This is the first North American report of Oidium longipes, an anamorphic powdery mildew species described recently in Europe. It was found on vegetatively propagated petunia grown in a commercial greenhouse in New Jersey, USA, where it caused a rapidly spreading disease. The pathogen might have originated offshore and may have already been distributed in the United States through horticultural trade.

Identification and Characterization of a Carlavirus Causing Veinal Necrosis of Coleus.

A filamentous virus identified in coleus (Coleus × hybrida) in Minnesota and New York was found to cause veinal necrosis in coleus, although this symptom was observed only under certain conditions. The virus was transmitted readily by mechanical inoculation to coleus and Nicotiana spp. and was not transmitted by Myzus persicae.

Principles of plant health management for ornamental plants.

Economic, environmental, and technological influences complicate the task of achieving disease-free products in the ornamentals industry. Integrated pest management (IPM) is a cornerstone of floriculture and nursery crop production: strategies include sanitation, clean stock, host resistance, and control through biological, cultural, environmental, chemical, and regulatory means. Sanitation measures and cultural controls must keep pace with new production technologies.

First Report of Erysiphe sedi on Sedum spectabile in North America.

Since 1997, powdery mildew infections have been repeatedly observed on Sedum spectabile plants, cv. Autumn Joy, grown as ornamentals in commercial greenhouses in New York. Circular patches of gray mycelia appeared and spread on upper and occasionally on lower leaf surfaces followed by necrosis of the leaf tissues and defoliation.