Effect of fungicides and spray regimes against Phytophthora leaf blight disease of taro cultivars in Nsukka, Southeastern Nigeria

Effects of fungicide types and spray regimes were assessed on Phytophthora leaf blight disease during the early and late cropping seasons in Nsukka, southeastern Nigeria. The field  experiment was laid out in 3 × 3 × 5 factorial in randomized complete block design with three replications in early and late cropping seasons of taro, respectively. The factors consisted of three Colocasia esculenta cultivars (Nachi (purple taro/Nce003), Odogolo (green taro/Nce002) and Ugwuta (Coco-India/Nce001); two fungicides (Ridomil Gold 66 WP plus, Ridomil Gold + Champ Drill Prill 50.00%:50.00% mixture and control); and five spray regimes (no spray, 1, 2, 3, and 4 weeks spray). Results showed that there were significant variations in disease incidence among the fungicides, spray regimes, cultivars and between seasons at 90, 120 and 150 days after planting. Disease incidences and severity varied among the fungicides, spray regimes, cultivars and between the seasons. The results on establishment percentage significantly differed among the cultivars and cropping seasons. Ugwuta cultivar significant had the highest establishment percentage in both cropping seasons at 15 and 30 days after planting. The growth attributes on plant height (cm) and number of leaves significantly varied among the fungicides, spray regimes, cultivars and between cropping seasons. Ridomil Gold 66 WP at weekly spray regime performed best compared to other fungicides and spray regimes. There were significant variations among the cultivars and cropping seasons at the sampling periods. Tuber yield significantly differed among the fungicides, spray regimes, cultivars and cropping seasons at harvest. Ridomil Gold 66 WP at weekly spray regimes, Odogolo cultivar and early cropping season performed best in all yield traits at harvest.