The Order Peronosporales, a group of fungal-like organisms commonly known as the water molds, incite many of the most devastating plant diseases worldwide. Two particular peronosperomycetes, Phytophthora capsici Leonian and Pseudoperonospora cubensis (Berk. and Curt.) Rostov., are a major threat for many Michigan vegetable crops. Phytophthora capsici, a limiting factor mainly for cucurbit and solanaceous production, was confirmed to infect snap bean (Phaseoulus vulgaris L.) in Michigan fields. Since dry edible beans are a variant of the snap bean species, we assessed eight dry edible bean cultivars for susceptibility to P. capsici. Different plant parts were inoculated independently with each of two P. capsici isolates. Results obtained in this study indicate that dry edible beans are susceptible to P. capsici under controlled conditions. Cucurbit downy mildew, caused by Pseudoperonospora cubensis is the most devastating foliar disease for cucurbits. Forty-one cucurbit cultigens (i.e., commercial cultivars and plant introductions) from five different genera were assessed for their susceptibility to natural infection by P. cubensis in a Michigan research field during 2010 and 2011. Results confirmed that Cucumis is the most susceptible genus to downy mildew, Citrullus cultigens presented small necrotic lesions, and no visible infection was found on cultigens of Cucurbita moschata and C. pepo.
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