Viral diseases are widespread in vineyards throughout the world. Vineyard viruses are mostly disseminated via vegetative propagation, although insect and nematode vectors can also be involved in the spread. Michigan faces challenges with grapevine viruses due to the following: (i) multiple Vitis sp. ( V. vinifera, V. labrusca, and Vitis interspecific hybrids) being cultivated within the state, (ii) vineyards that vary in age, and (iii) plant material being sourced from a variety of locations throughout the United States. Determining the distribution of grapevine viruses in Michigan is the first step in developing mitigation strategies. In this study, we utilized real-time reverse transcription polymerase chain reaction (RT-PCR) to test for a variety of grapevine viruses that are known to occur in other regions. Vineyards were sampled for grapevine leaf tissue ( n = 429) across the northwest, southwest, mid, and southeast regions of the lower peninsula of Michigan and were screened for a panel of viruses. Across all samples, grapevine rupestris stem pitting-associated virus (GRSPaV) was the most abundant. Other viruses found in relatively high abundance included grapevine leafroll-associated virus 3 (GLRaV3), grapevine fleck virus (GFkV), and tobacco ringspot virus (TRSV). Interestingly, this study identified grapevine red blotch virus (GRBV) and grapevine Pinot gris virus (GPGV) for the first time within the state. This survey gives researchers and growers an awareness of the distribution of viruses in Michigan vineyards that can aid management recommendations and encourage the use of virus-tested material from reputable sources when planting new vineyards.

Puccinia kuehnii is an important airborne fungal pathogen of sugarcane, causing orange rust disease. P. kuehnii has been present in the Asia–Oceania region for over a century. The first report of this pathogen in the Western Hemisphere was in 2007, when it appeared in Florida, U.S.A. The main objective of this diagnostic guide is to provide detailed information about symptoms and signs of sugarcane orange rust as well as taxonomy, geographic distribution, isolation, identification, and storage of P. kuehnii. We also highlight the management strategies used in recent years to control this devastating fungal disease. This diagnostic guide will help facilitate future research focusing on fungal isolation procedures, genetics, and population studies of this pathogen.

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a major yield-reducing pathogen of soybean ( Glycine max [L.] Merrill) in the United States and Canada, causing twice as much yield loss annually as any other pathogen. Reports of new discoveries of SCN in areas of the United States and Canada that grow the crop can lead to greater awareness of the pathogen and increased efforts to scout for the nematode. Beginning in January 2024, university nematologists, plant pathologists, and agronomists as well as government plant health officials in soybean-producing states in the United States and provinces in Canada were queried about the known distribution of the nematode. This publication contains an updated map of the known distribution of SCN in the United States and Canada through 2023 and a listing of counties and rural municipalities where the nematode initially was identified between 2000 and 2023. In total, there were 31 counties in 10 states in the United States plus three counties total in Manitoba and Ontario and 10 rural municipalities in Quebec, Canada, in which SCN was first discovered between 2020 and 2023. The results show that the distribution of SCN in the United States and Canada continues to expand, and sustained scouting for the presence of the pathogen is warranted to facilitate management to reduce soybean yield losses. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

A collection of foliar diseases affects table beet production in New York. The predominant diseases are bacterial leaf spot (BLS) caused by the bacterium Pseudomonas syringae pv. aptata; Cercospora leaf spot (CLS) caused by the fungus Cercospora beticola; and Phoma leaf spot (PLS) caused by the fungus Phoma betae (syn. Neocamarosporium betae). Little is known of the potential to use host resistance in an integrated program for table beet disease management. Field trials evaluated the susceptibility of selected table beet cultivars (Bohan, Bresko, Manolo, Pablo, Red Cloud, Ruby Queen, Subeto, and Bazzu/Irazu) to BLS, CLS, and PLS. Bohan was one of the least susceptible to BLS but was moderately and highly susceptible to CLS and PLS, respectively. Bresko was moderately susceptible to BLS and CLS and was among the least susceptible to PLS. Manolo was one of the least susceptible to BLS and PLS but was highly susceptible to CLS. Pablo and Red Cloud were moderately or highly susceptible to all diseases. Subeto was moderately susceptible to BLS and CLS but was the least susceptible to PLS. Ruby Queen, the processing standard, was the least susceptible to BLS and PLS and was moderately susceptible to CLS. Bazzu and Irazu (2021 and 2022, respectively) were among the least susceptible to all diseases and were the only cultivars tested with reduced CLS susceptibility. These findings emphasize the need to evaluate table beet cultivar susceptibility to the spectrum of foliar diseases. This information may underpin cultivar selection based on the varying importance of diseases in specific production situations.

Seed priming (a.k.a. seed treatment) is an excellent cost-effective practice to improve the growth and health of crop plants. Defense priming is a plant defense mechanism gained through the exposure to primary stimuli, which sets the plant up for more rapid and robust defense responses against severe biotic and abiotic challenges. Here, we discuss how the defense-priming mechanism could be implemented efficiently through the seed-priming technology and introduce previous related studies as the theoretical basis for this strategy to augment crop resistance.

On 8 August 2023, at a wholesale nursery in Nelson County, Virginia, approximately 500 Physocarpus opulifolius ‘summer wine’ plants in 11.4-liter containers were observed with leaf necrosis, shepherd's crook, and stem cankers. The isolates recovered from diseased tissue were identified as Phytophthora palmivora based on morphological and molecular analysis. A 778-bp segment of the internal transcribed spacer locus and 827-bp segment of the cytochrome c oxidase subunit 1 locus from isolate AE03 were deposited into the GenBank database under accessions OR754361 and OR760058, respectively. Koch's postulates were fulfilled by spraying a zoospore suspension on three healthy plants and incubating them in a chamber with over 90% humidity at 22 ± 2°C. After 72 h, all three inoculated plants displayed necrotic leaf and stem lesions, and approximately 25% of the leaves senesced. To the authors’ knowledge, this is the first documentation of Phytophthora palmivora causing aerial blight on plants in the genus Physocarpus.

Blackberry collapse is an emerging disease in Oregon caused by Gnomoniopsis idaeicola. Symptoms associated with the disease include cane lesions, reduced primocane production, wilting, and plant death. Symptomatic plants are removed to reduce disease spread in the field. Unfortunately, blackberry collapse symptoms can be difficult to differentiate from those of other non-lethal cane diseases. Diagnostic procedures for blackberry collapse currently require several weeks to complete, necessitating development of a species-specific PCR assay to identify G. idaeicola in culture and in planta. The assay targets tef-1α and β -tubulin and includes primers as internal controls for PCR reactions of plant tissue or fungal cultures. This species-specific assay will provide rapid diagnosis of blackberry collapse and aid with epidemiological studies.

Avocado scab, caused by the fungus Elsinoe perseae, is a major disease of avocado ( Persea americana). Diagnosis of avocado scab is hampered by the similarity that advanced symptoms have with fruit defects caused by other etiologies (e.g., mechanical injuries and insect feeding damage). The aims of this diagnostic guide were to establish key aspects of the identification of symptoms and signs of avocado scab in the field and laboratory and to provide guidance when conducting isolation, identification (i.e., based on morphological characteristics, molecular-based assays), maintenance, storage, and pathogenicity tests of the fungus E. perseae.

During the early 1990s, almond witches’ broom (AlmWB), a disease affecting stone fruits, was reported in Lebanon and Iran. The disease quickly escalated into an epidemic that destroyed hundreds of thousands of almonds, peaches, and nectarine trees due to its invasive and destructive nature. The causal agent was eventually identified to be ‘ Candidatus Phytoplasma phoenicium’, a phytoplasma belonging to subgroup 16SrIX-B. There are currently no effective curative treatments, making the eradication of infected trees the only remaining option. Therefore, stringent quarantine measures and potent detection tools are imperative for early detection and effective prevention of AlmWB phytoplasma. Although there are currently no commercially available phytoplasma detection serological tests, there are several PCR-based assays for the detection of ‘ Ca. P. phoenicium’ and other phytoplasmas. Consequently, the development of accurate and sensitive assays is needed. In this study, we designed primers for specific, sensitive, and simultaneous detection of 16SrIX-B (AlmWB) and 16SrIX-C (Picris echioides yellows) phytoplasmas without the need for restriction fragment length polymorphism. The PCR assays were highly efficient, specific, and reproducible for the detection of the two phytoplasmas in multiplex PCR. The multiplex assay detected AlmWB and Picris echioides yellows targets in mixed infections up to a sensitivity of 100 pg/µl of total plant DNA. Our developed multiplex PCR assay is suitable for quarantine screening of woody tree germplasm and for surveying aimed at discriminating 16SrIX-B, a quarantine pest, from the closely related 16SrIX-C, a non-quarantine phytoplasma, with the aim of preventing or mitigating AlmWB.

Ralstonia solanacearum is a species complex of bacterial plant pathogens that cause bacterial wilt on a wide range of crops in tropical and subtropical regions. Among the different subgroups of this complex, race 3 biovar 2 (R3bv2) is of particular concern because it can infect potato, tomato, and geranium in temperate climates and is regulated as a select agent in the United States. This document presents a recovery plan for R3bv2 as part of the National Plant Disease Recovery System (NPDRS) in the United States. The plan provides a brief overview of the disease; its taxonomy, distribution, detection, and management; and the current infrastructure, needs, and experts for effective response and recovery. It also identifies research, education, and extension priorities for mitigating R3bv2, such as developing disease management tactics, detection tools, an impact network analysis, and stakeholder education. The plan is intended to help the USDA guide further efforts directed toward plant disease recovery and to ensure a reasonable level of crop production in the event of a high-consequence plant disease outbreak.