A number of growers have reported of leaf spots appearing in spinach and other greens. Alternaria and Cladosporium leaf spots have been identified in fields in our region. Fields should be scouted on a regular basis to find ‘hot spots’. Look for numerous, light-brown to tan, round to oval spots developing on leaf surfaces. Like many pathogens, both Alternaria and Cladosporium can overwinter on undecomposed debris and become active under favorable weather conditions. Appropriate weekly fungicide maintenance programs should be started, if they haven’t already. Importantly, the fungicides used specifically to control downy mildew and white rust will not help against leaf spots. To date, no downy mildew or white rust has been reported. For leaf spot control, apply Quadris (azoxystrobin, 11) at 12.0 to 15.5 fl oz 2.08SC/A or Cabrio (pyraclostrobin, 11) at 12.0 to 16.0 oz 20EG/A rotated weekly with Fontelis (penthiopyrad, 7) 24.0 fl oz 1.67SC/A. Please see the 2013 Commercial Fungicide Recommendations Guide for more information.
