Plant Health Progress

A Diagnostic Guide of Diseases Caused by Diaporthe Species in Soybean | Plant Health Progress Species of Diaporthe cause major diseases in soybean (Glycine max [L.] Merr.), including Diaporthe (Phomopsis) seed decay, pod and stem blight, and stem canker. This diagnostic guide offers an overview of the symptoms caused by Diaporthe species, as wel...

Get a First Look 🔍: “A Diagnostic Guide of Diseases Caused by Diaporthe Species in Soybean,” by Milsha George et al.: https://doi.org/10.1094/PHP-03-25-0096-DG

FIGURE 1 States in which tomato high tunnel soil samples were obtained for soilborne disease survey in four survey years.

High tunnels protect plants, but conditions often result in the accumulation of soilborne pathogens in tomato. Manisha Hamal et al. evaluated the prevalence of soilborne pathogens in 265 tomato high tunnels on 118 farms from 12 states: https://doi.org/10.1094/PHP-01-25-0004-S

Genome-Wide Association Study Identified One Major Quantitative Trait Locus Associated with Resistance to Fusarium proliferatum in Soybean (Glycine max) | Plant Health Progress Fusarium root rot is a yield-limiting disease of soybean (Glycine max L.) in the United States and Canada (Ontario). Among the species of Fusarium causing root rot, F. proliferatum is a virulent pathogen. Sources of resistance to F. proliferatum have be...

Get a First Look 🔍: “Genome-Wide Association Study Identified One Major Quantitative Trait Locus Associated with Resistance to Fusarium proliferatum in Soybean (Glycine max L.),” by Nitha Rafi, Matias Dominguez, and Febina M. Mathew

FIGURE 5 Symptoms and signs of downy mildew affecting Lenten rose caused by Peronospora pulveracea. A and B, Diseased leaves displaying dark brown-to-black speckled lesions on adaxial leaf surfaces. C and D, White-to-brown floccose mycelial growth on the abaxial leaf surface. E, Sporangiophores emerging through stomata on the abaxial leaf surface. F, Sporangiophore. G, Close-up image of sporangiophore ramifications showing sporangia developing and ultimate branchlets. H, Sporangia. I, Oospore. Scale bars: C = 5 mm; D = 500 µm; E to G = 50 μm; H and I = 20 µm.

Where flowers bloom, so do downy mildews: Catalina Salgado-Salazar et al. report downy mildew observations on several annual, herbaceous perennial, and woody shrub plants in several states in the eastern United States. https://doi.org/10.1094/PHP-10-24-0100-RS

On this #WorldFoodDay, we celebrate the efforts of those who nourish our communities, protect our planet, and shape a better future through better food for all. Explore resources to learn more about food security and sustainability. #FAO80

https://bit.ly/4nqN3x7

FIGURE 4 USVL608-PMR showing intermediate resistance to powdery mildew isolate 677X608. However, USVL608-PMR was significantly (P = 0.05) less susceptible than USVL677-PMS to all the isolates evaluated in this study.

Physiological races of Podosphaera xanthii have not been classified for watermelon. Chandrasekar S. Kousik and Jennifer L. Ikerd developed a set of watermelon powdery mildew race differentials and identified potential races. 🍉 https://doi.org/10.1094/PHP-11-24-0114-RS

Plant Disease Management Reports (PDMRs) are now easier to navigate! A new update allows users to filter PDMRs by crop type and author, making it easier than ever to find relevant reports.

Explore PDMRs published in Plant Health Progress: apsjournals.apsnet.org/topic/pdmrar...

Field-scale evaluation of fungicide timing for corn diseases and yield in Indiana from 2019 to 2022 | Plant Health Progress Tar spot (Phyllachora maydis), gray leaf spot (Cercospora zeae-maydis), southern rust (Puccinia polysora), and northern corn leaf blight (Exserohilum turcicum) are foliar diseases that can significantly reduce corn (Zea mays) yields in Indiana. The obje...

Get a First Look 🔍: “Field-Scale Evaluation of Fungicide Timing for Corn Diseases and Yield in Indiana from 2019 to 2022,” by Kaitlin G. Waibel et al.: https://doi.org/10.1094/PHP-04-25-0103-RS @DTelenko

FIGURE 1 Symptoms caused by a mixed infection of cucurbit yellow stunting disorder virus (Crinivirus cucurbitae) and watermelon chlorotic stunt virus (Begomovirus citrulli) in watermelon plants: A and B, stunting; C to E, chlorotic mottling; and F, yellowing.

Since 2020, a disease syndrome on watermelon plants has been observed in Jalisco, Mexico. Hernández-Pérez et al. present the first report of CYSDV and WmCSV in a natural mixed infection in watermelon in Mexico 🍉: https://doi.org/10.1094/PHP-10-24-0096-BR

Get a First Look 🔍: “Comparison of Cuprous Oxide and Chlorothalonil Applied Alone and as Tank Mix Partners with Flutolanil or Inpyrfluxam for Management of Late Leaf Spot (Nothopassalora personata) of Peanut,” by Alana G. Atkinson et al.: https://doi.org/10.1094/PHP-02-25-0052-RS

FIGURE 1 Early symptoms of Botrytis head rot after insect damage.

Diagnostic Guide: “Sunflower Head Rot Diseases: Botrytis Head Rot and Bacterial Head Rot,” by Malcolm Ryley et al.: https://doi.org/10.1094/PHP-08-24-0077-DG

Get a First Look 🔍: “Occurrence of Plant-Parasitic Nematodes in Pacific Northwest Hopyards,” by Lester Antonio Núñez Rodríguez et al.: https://doi.org/10.1094/PHP-01-25-0011-RS

Examples of tuber and foliar symptoms observed in Potato virus Y (PVY)-positive diagnostic samples received from Michigan seed and commercial production. Prevalent strains detected include PVYN-Wi and PVYNTN, and strain results are shown above or below the external, internal, and/or leaf symptoms shown in each column. Tuber examples include public and proprietary chipping and yellow-fleshed varieties; foliar symptoms are shown in a russet variety. Using methods by Mumford et al. (2000), diagnostic samples tested negative for Potato mop top virus (PMTV) and Tobacco rattle virus (TRV).

Potato virus Y (PVY) strain surveys (2019–2023) across Michigan seed lots by Mio Satoh-Cruz et al. reveal PVYN-Wi as dominant, but necrotic strains like PVYNTN and PVYE persist. Continued monitoring is vital for management. Learn more: doi.org/10.1094/PHP-...

Symptoms of aerial stem rot (ASR) caused by Pectobacterium carotovorum. A, Initial infections occur through wounds such as petiole scars or insect damage and expand outward, creating a distinct black lesion. B, The lesion spreads down the stem, infecting petioles and eventually killing the stem. C, Severe ASR infection showing disease in four out of five stems on the plant. Note that the lesions have spread down the stem as healthy, green tissue can be seen around the base of the plant in the infected stems.

A decade-long study by Phillip S. Wharton, Alan Malek, and Katie L. Malek, published in Plant Health Progress, is the first to provide conclusive evidence that copper-based fungicides reliably manage aerial stem rot in potatoes. 🥔 Read the full press release: www.apsnet.org/about/newsro...

Wheat leaf with rust spores and dead tissue.

Illustration of disease cycle of Fusarium head blight.

560 million bushels gone. $2.9 billion lost.

These are the estimated losses caused by wheat diseases from 2018 to 2021. Read more in the new @planthealthprog.bsky.social publication at doi.org/10.1094/PHP-....

@badgercropdoc.bsky.social @alabamaed1.bsky.social
#science 🧪 #wheat #disease #IPM

Testing the Efficacy of a Newly Released Fungicide, Sphaerex, for Control of Fusarium Head Blight in Wheat | Plant Health Progress Fusarium head blight (FHB) is a destructive disease of wheat and other small-grain cereals. FHB causes reduction in crop yield due to premature bleaching of spikes. Additionally, it deteriorates the crop quality due to production of mycotoxins. An integrated management strategy is needed to effectively manage this disease. One of the most important strategies in the FHB management toolbox is chemical control. Fungicides start losing their efficacy over time due to the development of fungicide resistance in the pathogens. This necessitates the development and testing of new fungicides with multiple active ingredients or modes of action. In this 3-year study, we evaluated the effectiveness of a new fungicide with multiple active ingredients, Sphaerex (a proprietary mix of metconazole and prothioconazole), in an FHB-susceptible soft red winter wheat cultivar, Shirley, in the eastern United States. Sphaerex provided significantly better control over untreated plots for FHB incidence, FHB severity, and deoxynivalenol (DON) content across all 3 years. The level of control of FHB and DON by Sphaerex was found to be similar to that provided by other standard FHB fungicides. The yield of the fungicide-treated plots was statistically similar to that of the untreated plots.

A 3-year study by Bhavit Chhabra et al. in the eastern U.S. showed that the fungicide Sphaerex effectively controlled Fusarium head blight and deoxynivalenol levels, with similar results to standard fungicides. @umnplantpath.bsky.social doi.org/10.1094/PHP-...

Starting this year, Plant Disease Management Reports (PDMRs) will be published in Plant Health Progress. With this change, PDMRs now offer year-round submission with prompt publication upon acceptance. Learn more: apsjournals.apsnet.org/page/php/pdmr

Three-week-old cultures of Berkeleyomyces rouxiae on potato dextrose agar (PDA) showed some degrees of morphological variation: A, dark pigmented colony with some exudate droplets on the surface; B, colony with albino sectors developed as a result of serial subculturing; and C, hyaline to subhyaline rod-shaped endoconidia and club-shaped dark pigmented chlamydospores that are chains of singular cells.

Black root rot is a significant seedling disease in Australian cotton. This guide by Duy P. Le et al. offers diagnostic tools, pathogen isolation methods, molecular identification techniques, and pathogenicity assessment approaches. doi.org/10.1094/PHP-...

Symptoms of Cercospora leaf spot caused by the fungus Cercospora beticola begin as A, small spots with a gray center and B, rapidly coalesce to encompass the leaf, resulting in defoliation.

Foliar diseases affect table beet production in New York. Field trials by Pratibha Sharma et al. show varying susceptibility among cultivars, with Bazzu and Irazu offering the best resistance to all three diseases. doi.org/10.1094/PHP-...

Thank you for this recognition @planthealthprog.bsky.social @plantdisease.bsky.social! 🎊🥳

Symptoms observed in small fruits and grapevines infected with tomato ringspot virus (ToRSV). A, Shortening internodes and decline on wine grape; B, ringspots on blueberry; C, vein clearing on red raspberry; and D, mosaic on red currant.

Small fruit crops are vital to the Pacific Northwest. A new study by Cristian Olaya et al. reveals dagger nematodes in 52% of fields surveyed and reports ToRSV in Oregon wine grapes and red currants for the first time, updating virus-vector data. Learn more: doi.org/10.1094/PHP-...

"The...significant effect of hybrid susceptibility on disease severity & yield suggests...use of genetic resistance may be more effective in tar spot...management than altering plant density."

From @planthealthprog.bsky.social's pub apsjournals.apsnet.org/doi/10.1094/...

@plantdisease.bsky.social

The reniform nematode is a major yield-limiting pest in tropical and subtropical crops. This updated map from Travis R. Faske et al. shows its county-level distribution in U.S. field crops, aiding targeted management. doi.org/10.1094/PHP-... @mahduffeck.bsky.social