Abstract:
In Sri Lanka, the coconut industry, which is a
major contributor to the national economy, is
under severe threat from the recently introduced
pest, the coconut whitefly (Aleurodicus cocois).
This pest’s resistance to conventional pesticides
combined with the height of coconut trees has
highlighted the need for sustainable management
alternatives. The aim of this study is to develop
and evaluate a plant semiochemical-based
strategy for coconut whitefly control, using stem
injection as a systemic alternative to chemical
pesticides. The approach offers a sustainable
solution by reducing pest populations without
negatively impacting the ecosystem. Plant
extracts of seeds and leaves of Strychnos nux
vomica (Goda kaduru), neem, mint and clove oil
were formulated and tested. Four successful
formulations were identified and initially tested by
direct spraying. Building on these results, the
formulations were combined with systemic
recipients such as urea, NaCl, KCl and citric acid
and evaluated by strain injection methods. Field
trials showed significantly higher mortality rates
(68%, 95.85%, 93.27% and 94.66%) for
formulations 1 to 4 compared to the untreated
control (p < 0.005). Stem-injected palms showed
a
gradual decline in whitefly populations,
although adverse weather conditions prevented
continuous monitoring. These findings suggest
that repeated applications are necessary for long
term success.
