Introduction

Pumpkins are important crops in Illinois. In the United States (US), Illinois ranks first in pumpkin (Cucurbita pepo L.) production. Approximately 90% of the commercial processing pumpkins (Cucurbita moschata Poir.) in the US are grown in about 10,000 acres and processed in Illinois. Also, about 12,000 acres of jack-o-lantern pumpkins and 8,000 acres of other cucurbit crops including cucumber (Cucumis sativus), melons [Cucumis melo L., Citrullus lanatus (Thumb.) Matsum & Nakai], and squashes (Cucurbita pepo L.) are annually grown in Illinois.

Several diseases are serious threats to pumpkin production in Illinois. Among important diseases are: Alternaria blight (Alternaria cucumerina), Anthracnose (Colletotrichum orbiculare), Downy mildew (Pseudoperonospora cubensis), Fusarium crown and fruit rot (Fusarium solani f. sp. cucurbitae), Gummy stem blight and black rot (Didymella bryoniae), Phytophthora blight (Phytophthora capsici), Plectosporium blight (Plectosporium tabacinum), Powdery mildew (Podosphaera xanthii), and viral diseases (e.g., cucumber mosaic, Papaya ringspot, Squash mosaic, Watermelon mosaic, and Zucchini yellow mosaic). Among these diseases, Phytophthora blight (P. capsici) is the most important disease of pumpkin in Illinois.