Chemical control of “ in vitro” fungal pathogens in taro rhizomes with Celest 0.25 FS and Celest Top 312

Abstract

Root rot in cocoyam (Colocasia esculenta, Xanthosoma saggitifolium) is caused by various pathogens, among which are: F. sulfureum, F. solani, F. chlamydosporum, F. oxysporum, S. rolfsii, R. solani, Phoma sp.Diplodia sp., R. nigricans. Within the principal fungicides registered in Cuba for seed protection are mancozeb,captan, benomyl, tiran, carboxin + tiran, thiabendazole, guazatine and propamocarb among others, which are used against many fungi pathogen genera. In order to study the “in vitro ” chemical control effectiveness of Celest 0.25 FS and Celest Top 312 in combating these pathogens, this study was performed in the Phytopathology laboratory from the Research Institute of Tropical Root and Tuber Crops (INIVIT). The Potato Dextrose Agar (PDA) medium that was poisoned at doses of 180, 300 and 500ppm with fungicides Celest 0.25 FS and Celest Top FS 312 was used. The fungal pathogens studied were: Fusarium sulfureum, Sclerotium rolfsii, Rhizoctonia solani and Phoma sp. Measurements were made on mycelial growth after 48, 72, 96, 120 and 144 hours alter planting. The best results in the application of Celest 0.25 FS is obtained with the dose of 500 ppm. Doses of 180 and 300 ppm exert little effect on these pathogens. Top Celest doses 312 FS (300 and 500 ppm), are very effective on “in vitro” control of fungal species tested, showing a limited radial 0.9 and 0.4 cm respectively as average.

Keywords

• fungicides
• taro
• dry rot