Effectiveness of raised bed planting for managing Phytophthora induced gummosis in Nagpur mandarin (Citrus reticulata Blanco)

Phytophthora diseases have been identified as one of the major causes of citrus decline. The present study investigates the prevalence of Phytophthora-induced gummosis, crown rot, collar rot, and foot rot in mature Nagpur mandarin orchards under flat (conventional) versus raised bed planting systems. An intensive rapid roving survey was conducted during two seasons of 2023 and 2024 to assess the incidence of gummosis-affected trees using a 0–4 disease rating scale. Results revealed a significantly lower incidence of gummosis in raised bed orchards (3.12%-21.66%) compared to flat/conventional systems (34.61%-59.44%). Similarly, the Phytophthora propagule density in soil was markedly lower in raised bed orchards (2.01%-3.01%) than in conventional orchards (28.63%-33.75%). Raised beds (600 mm height, 2–2.5 m width) provided better drainage, improved soil aeration and enhanced root stability, collectively reducing disease incidence and improving the tree resilience under adverse conditions. These findings highlight that most farmers still follow conventional flat planting methods, which favor water stagnation and disease development. Therefore, large-scale demonstrations and promotion of raised bed planting techniques are strongly recommended for effective management of Phytophthora diseases in Nagpur mandarin, especially in orchard facing waterlogging issue during rainy seasons, a common feature prevalent in central India.