MORPHOLOGICAL AND MOLECULAR IDENTIFICATION OF Phytophthora capsici IN Cucurbita argyrosperma Hort. ex L.H.Bailey, AND GREENHOUSE HANDLING

Abstract

Cushaw pumpkin (Cucurbita argyrosperma) is important in the diet, its seeds are consumed toasted and salted, and they are the main ingredient to make typical Mexican dishes and various traditional sweets; however, some fungi cause severe problems in its fruits, thus reducing its yields. The morphological and molecular identification of the oomycete involved in cushaw pumpkin fruit rotting was performed, and alternatives for chemical and biological control under greenhouse conditions were evaluated. Cushaw pumpkin fruits with different symptoms and levels of rotting were collected (August- September, 2011), in the northern zone of the state of Guerrero, México, and after their morphological identification, DNA from the fungus was extracted for its PCR analysis, using oligonucleotides that amplify the internal intergenic spacer (ITS). Both techniques identified Phytophthora capsici in cushaw fruits, and the PCR amplification products were compared with those available at the GenBank. The sequences showed 99 % of similarity with sequences from watermelon and squash. The active ingredients for its control (propamocarb+fosetyl and metalaxyl+chlorothalonil), exerted the best control by delaying the presence of the pathogen in cushaw pumpkin fruits.