Biocontrol agents for Sustainable Management of Bud Rot Disease in Coconut Nursery

Abstract

Phytophthora palmivora, an oomycete pathogen responsible for coconut bud rot, poses a significant threat to palms of all ages, with substantial economic implications. This research aimed to address this challenge by implementing eco-sustainable management strategies through the utilization of a synergistic combination of biocontrol agents. The study focused on combating coconut bud rot in both nursery and main field settings. In the nursery, the study employed a soil application of Trichoderma asperellum at a rate of 25g per cent during sowing, combined with crown application of Bacillus subtilis at a concentration of 10g per liter of water, administered twice at three-month intervals and six months after sowing. Additionally, an application of Arbuscular Mycorrhizal (AM) fungi at 50g per cent three months after sowing was implemented. This multi-pronged approach proved 77.12 per cent effective in suppressing bud rot disease within the nursery environment. For young coconut gardens, a randomized design with three replicates was used to evaluate the treatments. The results indicated that a soil and crown application of B. subtilis at 10g per liter of water, performed twice - first during the pre-monsoon period (last week of May) and secondly in the post-monsoon period (September) - significantly reduced bud rot incidence. Additionally, the application of T. asperellum at a rate of 50g per palm and AM fungi at 50g per palm annually in January demonstrated 71.73 per cent effectiveness in mitigating the occurrence of bud rot in young coconut gardens. This research underscores the practicality and efficacy of employing a carefully curated combination of biocontrol agents within eco-sustainable management practices to combat the economically detrimental coconut bud rot disease in various coconut palm cultivation settings.