Tar Spot: An Understudied Disease Threatening Corn Production in the Americas.

Tar spot of corn has been a major foliar disease in several Latin American countries since 1904. In 2015, tar spot was first documented in the United States and has led to significant yield losses of approximately 4.5 million t. Tar spot is caused by an obligate pathogen, Phyllachora maydis, and thus requires a living host to grow and reproduce. Due to its obligate nature, biological and epidemiological studies are limited and impact of disease in corn production has been understudied. Here we present the current literature and gaps in knowledge of tar spot of corn in the Americas, its etiology, distribution, impact and known management strategies as a resource for understanding the pathosystem. This will in tern guide current and future research and aid in the development of effective management strategies for this disease.

Identification of Fungal Communities Within the Tar Spot Complex of Corn in Michigan via Next-Generation Sequencing.

Tar spot is a fungal disease complex of corn that has been destructive and yield limiting in Central and South America for nearly 50 years. Phyllachora maydis, the causal agent of tar spot, is an emerging corn pathogen in the United States, first reported in 2015 from major corn producing regions of the country. The tar spot disease complex putatively includes Monographella maydis (syn. Microdochium maydis), which increases disease damage through the development of necrotic halos surrounding tar spot lesions. These necrotic halos, termed "fish-eye" symptoms, have been identified in the United States, though Monographella maydis has not yet been confirmed. A recent surge in disease severity and loss of yield attributed to tar spot in the United States has led to increased attention and expanded efforts to understand the disease complex and how to manage it. In this study, next-generation sequencing of the internal transcribed spacer-1 (ITS1) ribosomal DNA was used to identify fungal taxa that distinguish tar spot infections with or without fish-eye symptoms. Fungal communities within tar spot only lesions were significantly different from communities having fish-eye symptoms. Two low abundance OTUs were identified as Microdochium sp., however, neither were associated with fish-eye symptom development. Interestingly, a single OTU was found to be significantly more abundant in fish-eye lesions compared to tar spot lesions and had a 91% ITS1 identity to Neottiosporina paspali. In addition, the occurrence of this OTU was positively associated with Phyllachora maydis fish-eye symptom networks, but not in tar spot symptom networks. Neottiosporina paspali has been reported to cause necrotic lesions on various monocot grasses. Whether the related fungus we detected is part of the tar-spot complex of corn and responsible for fish-eye lesions remains to be tested. Alternatively, many OTUs identified as Phyllachora maydis, suggesting that different isolate genotypes may be capable of causing both tar spot and fish-eye symptoms, independent of other fungi. We conclude that Monographella maydis is not required for fish-eye symptoms in tar spot of corn.

A novel preparative regimen for autologous transplant in non-Hodgkin's lymphoma: long-term experience with etoposide and thiotepa.

The purpose of this study was to evaluate the efficacy and toxicity of the preparative regimen of thiotepa and etoposide in patients undergoing autologous transplantation for relapsed non-Hodgkin's lymphoma. The study involved 65 consecutive patients who underwent autologous transplantation using the thiotepa/etoposide regimen for relapsed intermediate-grade NHL at the University of Wisconsin Hospital and Clinics (UWHC) between 1987 and 2001. The regimen consisted of thiotepa 300 mg/m(2)/day and etoposide 700 mg/m(2)/day on days -6, -5, and -4. The median age at the time of transplant was 49 years. A total of 50 patients (76%) had diffuse large-cell lymphoma. A total of 50 (77%) patients had chemosensitive disease, and 15 (23%) were chemoresistant. With a median follow-up of 34 months (range, 3-163), 28 patients (43%) remain in CR and 33 (51%) have developed recurrent or progressive disease. The overall survival and event-free survival at 3 years are 40% (95% CI 26-53%) and 32% (95% CI 20-45%), respectively. There was one death attributed to regimen-related toxicity (RRT). Reversible gastrointestinal toxicity was the major RRT, and there was minimal pulmonary and cardiac toxicity. We conclude that the combination of thiotepa and etoposide is an effective preparative regimen with acceptable RRT.