From Invasion to Sustainable Management of the Coconut Whitefly Complex in India: Evidence, Knowledge Gaps and Research Priorities
S. Soorya Gayathri *
Department of Agricultural Entomology, College of Agriculture, Padannakkad, Kasaragod, Kerala – 671314, India.
V. Nisha Lekshmi
Department of Agricultural Entomology, Regional Agricultural Research Station, Pilicode, Kasaragod, Kerala – 671310, India.
M. S. Nisha
Department of Agricultural Entomology, College of Agriculture, Padannakkad, Kasaragod, Kerala – 671314, India.
M. Sujithra
ICAR-National Bureau of Agricultural Insect Resources (NBAIR), Bengaluru, Karnataka – 560064, India.
P. K. Sajeesh
Department of Plant Pathology, Krishi Vigyan Kendra, Pattambi, Palakkad, Kerala – 679306, India.
A. Devika
Department of Agricultural Entomology, College of Agriculture, Padannakkad, Kasaragod, Kerala – 671314, India.
E. K. Nandit
Department of Agricultural Entomology, College of Agriculture, Padannakkad, Kasaragod, Kerala – 671314, India.
*Author to whom correspondence should be addressed.
Abstract
India’s coconut agroecosystems now host a complex of five exotic whiteflies, comprising the rugose spiralling whitefly (RSW), Aleurodicus rugioperculatus, Bondar’s nesting whitefly, Paraleyrodes bondari, the nesting whitefly P. minei, the palm whitefly Aleurotrachelus atratus, and the established spiralling whitefly Aleurodicus dispersus. This review synthesises evidence from 2016 to 2026 on invasion history, identification, biology, host range, damage, seasonal dynamics, natural enemies and management, while appraising the strength of the available evidence. Quantitative yield-loss estimates are available mainly from Andhra Pradesh and indicate losses of approximately 8%, 27% and 31–33% at low, medium and high RSW infestation, respectively. However, the evidence is largely single-season and regional, with no published multi-year yield assessments, economic injury levels or validated action thresholds. Seasonal population peaks vary among regions and species, indicating that a single dry-season model is not supported. Conservation biological control centred on Encarsia guadeloupae and the pesticide-holiday approach is supported principally by observational and institutional evidence, whereas field evaluations of biorational options remain mostly small and site-specific. Key research priorities include multi-year damage–yield studies, threshold-based decision rules, species-level surveillance, investigation of interactions among complex members, insecticide-resistance baselines and independently validated forecasting. A conceptual threshold-driven framework is therefore proposed for testing in area-wide trials. Addressing these evidence gaps would support locally informed and measurable management decisions for the coconut whitefly complex.
Keywords: Aleurodicus rugioperculatus, Paraleyrodes bondari, Aleurotrachelus atratus, Cocos nucifera, invasive alien species, Encarsia guadeloupae, conservation biological control, economic threshold, integrated pest management