Abstract:
Coconut (Cocos nucifera L), an important plantation crop in Sri Lanka, faces
productivity problems due to various biotic factors, with whitefly damage
posing a significant threat as it promotes the growth of black sooty mold. The
mold culture on the leaf surface reduced photosynthesis and thus reduced
yield. Therefore, it is necessary to control the formation of mold after the
whitefly has settled on the fronds. This study addresses the limitations of
chemical pesticides and explores eco-friendly alternatives to mitigate the
impact of black sooty mold fungus in field conditions. Fungicide agents and
plant extracts were compared, and antifungal compounds from plant
materials such as clove leaf, turmeric leaf, garlic, pandan leaf, Senna alata,
Jesmine leaf and holy basil were identified. Black mold was isolated,
cultured, and confirmed in the laboratory. Two nano formulations were
created based on preliminary observations: one with 5% jasmine and 1%
geraniol, and the other utilizing 5% clove oil. Laboratory experiments
applied these formulations at 10% concentrations in Potato Dextrose Agar
(PDA) media to culture black sooty mold fungus, comparing the results with
a control as a completely randomized design with 6 replicates. Results
indicated no mold growth on plates treated with both formulations, while
control plates exhibited mold growth after two days. Continuous observation
revealed inhibition of mold growth for up to two months with formulation
two, whereas formulation one exhibited mold initiation after three weeks.
Further experiments conducted with both the formulations were incorporated
with whitefly toxic compounds were treated to the infested palm through
trunk injection. Treated palms exhibited delayed reduction in mold growth on
new fronds, with no reduction observed on existing molds. Continuous
monitoring and repeated application through further research are essential
for conclusive results.
