Rhizoctonia root rot and stem canker caused by the soilborne fungus Rhizoctonia solani can be a significant challenge in Wisconsin tomato production, especially under cool soils, excessive moisture, compacted soils, or where tomatoes follow susceptible vegetable crops. Disease symptoms often begin shortly after transplanting and include stem constriction at the soil line, poor root development, …
Wisconsin potato growers have increasingly reported concerns with black dot and silver scurf over the past several years. These diseases are often subtle during crop development yet can significantly impact tuber appearance, storability, and marketability by harvest and throughout storage. Unlike explosive diseases such as late blight, black dot and silver scurf tend to develop …
Hollow heart, depending on its severity, is also called brown center. Hollow heart is characterized by the formation of an irregular cavity in the flesh of the tuber, usually surrounded by dark brown tissues. Heat necrosis is also referred to as internal brown and internal necrosis, which is characterized by small, brown, necrotic lesions or spots inside the vascular ring of the tuber.
While every growing season typically offers a few weather hiccups, some years offer a few more extreme disruptions than typical. Extreme temperatures, in concert with moisture stress, exacerbate disease risk at the time of harvest and beyond.
As the potato harvest season advances, late-season tuber diseases are of concern. Two diseases in particular—black dot (Colletotrichum coccodes) and silver scurf (Helminthosporium solani)—can diminish tuber quality, reduce storability, and lead to post-harvest losses. Managing these diseases requires careful attention in the late season, as cultural and harvest practices can influence disease.