News and Views

Disease: downy mildew
Pathogen: Peronospora parasitica
Hosts: cabbage and other crucifers (brassicas)

This delicate tree-like structure is one example of the elegance of the microscopic world. It is the asexual reproductive structure of the downy mildew pathogen, Peronospora parasitica. The sporangia are blown to new host plants for infection. Relative humidity and leaf moisture are important factors in the development of downy mildews. Control of these factors is important to controlling these diseases. (Courtesy of G. A. Payne)

License to Copy. This notice hereby grants permission to APSnet users to copy the Image of the Week for noncommercial, personal use. All components of APSnet are copyrighted (including the Image of the Week) and may not be reproduced or distributed except by express permission of APS. Copyright is not claimed for material provided by United States government employees as part of their work. APSnet copyright extends to images, text, graphics, photographs, illustrations, audio, video, computer software, and all other elements of the site.

Instructions to Copy. For PC, position your mouse cursor on the week’s image, click the right mouse button, and choose "Save Picture As..." or "Save this Image as..." whichever is the case. For Mac, click the only mouse button and follow the same steps. Users may want to set up a specific directory and file naming scheme for storing images; otherwise, they will be saved using your system defaults. Images may be used in any software application that supports JPEG file format or viewed in an Internet browser as local files.