Survey on fungal diseases affecting vegetable crops in Southern Puerto Rico.

Vegetable crops as a group are the fourth most important crop commodity in Puerto Rico, preceded by starchy crops, fruit crops and coffee commodities. Their production value for 2001-02 was close to $27 million (Department of Agriculture, 2002). Although vegetable crops have a high economic impact on Puerto Rico's agriculture, during the past ten years no local research has evaluated fungal diseases affecting them. In Puerto Rico, various fungal diseases causing damage to different vegetable crops have been reported. In cucurbits, including tropical pumpkin [Cucurbita moschata (Duchesne ex Lam.)], watermelon [Citrullus lanatus (Thunb.) Matsum. & Nak.], cucumber (Cucumis sativus L.) and melons (Cucumis melo L.), Ruiz-Giraldo (1986; 1992) mentioned the fungi Pseudoperonospora cubensis and Erysiphe cichoracearum causing downy mildew and powdery mildew, respectively, and Dydimella bryoniae (syn. Mycosphaerella melonis), producing gummy stem blight. He also reported target spot, caused by Corynespora cassiicola, mainly affecting cucumber. Also reported was the southern blight, caused by Sclerotium rolfsii, affecting eggplant (Solanum melongena L.), pepper (Capsicum annuum L.), tomato (Lycopersicon esculentum L.) and beans (Phaseolus vulgaris L.) in Puerto Rico (Ruiz-Giraldo, 1986). Leveillula taurica is known to cause powdery mildew in pepper (Negron et al., 1991; Ruiz-Giraldo, 1986; Ruiz, 1990; Ruiz-Giraldo and Rodriguez, 1992), whereas Phytophthora sp. causes pepper blight (Ruiz-Giraldo, 1986; Ruiz, 1990). In tomatoes, Phytophthora infestans was reported causing late blight (Ruiz-Giraldo, 1986; 1990) and Fulvia fulva (syn. Cladosporium fulvum) causing leaf mold (RuizGiraldo, 1990). Martin and Hepperly (1987) mentioned early blight, caused by Alternaria solani, as a limiting factor for successful year-round tomato production in Puerto Rico. In cabbage (Brassica oleracea L., Capitata Group), Monllor (1992) mentioned downy mildew (Peronospora sp.), leaf spot (Alternaria sp.), damping-off (Pythium sp. or Rhizoctonia sp.) and wire stem (Rhizoctonia sp.) as some of the most common diseases affecting this crop. Ruiz (1989) reported Alternaria porri, causing purple blotch, and Peronospora destructor, causing downy mildew, as two important fungal diseases in onion (Allium cepa L.) production. Fornaris et al. (1990) observed black mold (Aspergillus niger) in onion bulbs under storage. Reports published in The Journal of Agriculture of the University of Puerto Rico (JAUPR) before 1986 on fungal diseases affecting vegetable crops are the ones by Stevenson (1917), Matz (1921), Toro (1923), Nolla (1926,1929), Alvarez-Garcia (1946,1947), and