Maryland pansy growers see increase in leaf spots

Some Maryland pansy growers are encountering problems with Cercospora leaf spot. Univ. of Md. Coop. Ext. personnel report the spots tend to be on older leaves or leaves close to the growing medium surface. Initially the spots are 1-3 mm in size with a sunken center. They become dark gray or purplish in color and have a feathery appearance. If left untreated, the spots will continue to expand, coalesce and may cover the entire leaf. Infected leaves may turn yellow and drop off the plant. Plants with severe symptoms should be discarded. Keep the leaves as dry as possible. Irrigating the plants early in the morning allows the leaves to dry off and remain dry as temperatures and light levels decrease in the evening. Fungicides labeled for Cercospora on pansy include: mancozeb (Dithane T/O, Protect DF and others), thiophanate methyl (Cleary’s 3336), fludioxonil (Medallion), and chlorothalonil + thiophanate methyl (Spectro 90 WDG).