Managing Downy Mildew in Spinach

Tim Hammerich

News Reporter

Downy mildew is a significant disease on many crops, including spinach. This is especially true for organic producers that have fewer tools at their disposal to fight the pathogen. A three-year research project led by Ali Montazar, irrigation and water advisor for the University of California Cooperative Extension is studying if drip irrigation can help.

Montazar… “So can we reduce Downy mildew incidents by using drip irrigation, and also can we produce profitable spinach under drip? Those were the two main questions we answered.”

The study is now in its final stages at the UCCE Center in Holtville. Montazar says he is very encouraged by the results he is seeing.

Montazar… “We conducted several treatments. Different spacing, different depth of drip lines, different nitrogen management, and even germination by drip. So arethoseall the treatment we studied here in the last three years. And the results are promising. We found we can reduce four to five times Downy mildew incidents by using drip irrigation compared to sprinkler irrigation. Because the control treatment was sprinkler irrigation. So we compared everything by sprinkler. So I think four or five times Downy mildew incidents decreased is a huge impact for the industry.”

Montazar says this is the first experiment of its kind that he’s aware of in California, or anywhere.