Meios de cultura para o desenvolvimento de Choanephora sp. e Corynespora cassiicola

Abstract

The fungi Choanephora sp, the causative agent of leaf wilt in crotalaria and Corynespora cassiicola, the causative agent of the target stain in cotton, have low sporulation values in artificial culture media, which makes it difficult to produce spores under laboratory conditions. The objective of this study was to evaluate different culture media for the development of mycelial growth and sporulation of Choanephora sp. and Corynespora cassiicola. The most used medium in laboratories is Potato Dextrose Agar (BDA), using potatoes as a source of starch for their development. Other sources of nutrients such as sweet potatoes (Ipomoea batatas), carrots (Daucus carota), oats (Avena sativa), rice (Oryza sativa), tomatoes (Solanum lycopersicum) and molasses soybean were used as alternative means in this work. Mycelial growth and pathogen sporulation assessments were performed at the end of each assay. The data were submitted to analysis by the Tukey test at 5%. Soy molasses culture medium obtained higher growth rate for Choanephora sp., soybean isolate; and soy molasses and BDA presented the best results for Choanephora sp., crotalaria isolate. For C. cassiicola, the medium that stood out was sweet potato + BDA. For the area under the mycelial progress curve the best medium was sweet potato + BDA for all isolates and for Choanephora sp. sporulation, soybean and crotalaria isolates. For C. cassiicola the rice culture medium showed the highest sporulation.