Identification of Colletotrichum species associated with brown spot of cactus prickly pear in Brazil

Cactus prickly pear ( Nopalea cochenillifera ) is native to Mexico and is widespread throughout the world. In Brazil, this plant is cultivated exclusively in the Northeast region. Although presenting extreme rusticity and adaptability to the conditions of the Northeast, cactus prickly pear suffers from the attack of pests and diseases that can significantly reduce its productive potential. The objective of this study was to conduct a molecular and morphological characterization of Colletotrichum species associated with brown spot disease of cactus prickly pear. Cladodes showing symptoms of brown spot were collected in producing areas in the states of Alagoas and Pernambuco. The fungal isolates were identified molecularly using the GAPDH , TUB2 and ITS-rDNA genic regions, along with morphological characterization. Several isolates obtained from diseased tissue were identified as Colletotrichum : C. siamense , C. fructicola and C. karstii . To the best of our knowledge, this is the first report of the association of C. siamense , C. fructicola and C. karstii with brown spot in cactus prickly pear worldwide.