Prevalence of Phytophthora Leaf Blight of Taro (Colocasia esculenta (L.) Schott) in the Semi Deciduous Forest Zone of Ghana

Aim: The aim was to assess the incidence, severity and symptoms of the leaf blight of taro.

Methodology: A survey of 50 taro fields was conducted during the major cropping season of 2015 in 11 districts of the semi deciduous forest zone of Ghana. Disease incidence and severity were calculated and samples collected. Isolation, morphological identification and Koch’s postulate of the associated pathogen was carried out at the Plant Pathology Laboratory of the CSIR-Crops Research Institute, Kumasi, Ghana.

Results: Phytophthora colocasiae Raciborski, was identified as the causal pathogen of the leaf blight disease attacking taro. The study revealed a high incidence and severity of the disease across all locations surveyed. Incidence ranged from 30% in the East Akim District to 92.5% in the Tano South district whilst severity ranged from 6.5% to 86.5% in the East Akim and Tano North districts respectively. Disease incidence and severity was significantly different (P < 0.05) across the districts surveyed. Symptoms of the disease included multiple circular spots on the leave surface, white mycelia on lesion surface; shot holes on affected parts and water soak beneath the developed spots.

Conclusion: The current study revealed a high incidence and severity of the disease in the surveyed districts and has laid the foundation for extensive studies on the epidemiology of the disease in Ghana and the need to develop management strategies to reduce its impact.