A new technique will helpplant growers and others fight basils number one enemy: downy mildew. Early detection of this pathogen is difficult because its key symptom,yellowing of the leaves, mimics that of nitrogen deficiency. Misdiagnosis allows the pathogen to proliferate and often wipe out entire batches ofthe crop. While it is possible to conduct DNA-based assays to findthe source of the problem, that technique is difficult to use outside of a lab setting. Now researchers have developed a formula called Visikol that lets them visualize the desired part of the plant by distorting other parts. After adding Visikol to fresh basil leaves, they then stained the leaves with iodine to provide a high-contrast image between the pathogen and remaining plant material. That process should enable breeders to identify downy mildew under very low magnification. Even a magnifying glass can do the job, according the authors. The authors alsoplan to test the approach on other commercially important crops. Reference: Rapid