Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
Scout spinach for downy mildew and white rust on a regular basis, especially if spring plantings are near overwintered fields. Beginning 2 to 3 weeks after emergence (and prior to symptom development), apply the following on a 7 to 10-day schedule: Quadris (azoxystrobin, 11) at 6.0 to 15.5 fl oz 2.08F/A (use high rate for downy mildew), or Cabrio (pyraclostrobin, 11) at 12.0 to 16.0 oz 20EG/A (use lower rate for white rust only). Rotate to one of the following fungicides: Actigard (acibenzolar-S-methyl, P) at 0.75 oz 50WG/A, or Aliette (fosetyl Al, 33) at 3.0 lb 80WDG/A, or fixed copper (FRAC code M1) at labeled rates (copper containing fungicides may cause some phytotoxicity), or Ridomil Gold Copper (mefenoxam + copper, 4 + M1) at 2.5 lb 65WP/A (on a 14-day schedule). For more information please see the Delaware Commercial Vegetable Production Recommendations Guide.