Population Dynamics of Bemisia tabaci Biotypes in Relation to Host Plant Diversity in Mixed Vegetable Farms

Abstract

Whitefly, Bemisia tabaci, is a highly polyphagous pest complex that severely affects vegetable production systems through direct feeding damage and transmission of plant viruses. The present study investigates the population dynamics of B. tabaci biotypes in relation to host plant diversity in mixed vegetable farming systems. Field surveys were conducted across diversified cropping fields comprising tomato, chilli, brinjal, cucumber, and okra, and whitefly populations were monitored at regular intervals using systematic leaf sampling and yellow sticky traps. Morphological identification was supplemented with molecular characterization using mitochondrial cytochrome oxidase I (mtCOI) gene sequencing to distinguish biotypes. Results revealed the coexistence of multiple B. tabaci biotypes within the same agroecosystem, indicating high genetic diversity and host adaptability. Population density varied significantly among host plants, with higher infestations recorded on highly preferred hosts such as tomato and chilli. Host plant diversity influenced temporal fluctuations, with mixed cropping systems supporting continuous whitefly availability due to staggered host suitability. Molecular analysis confirmed distinct clustering of biotypes, suggesting differential host preferences and adaptation patterns. Environmental factors, particularly temperature and relative humidity, further influenced population build-up and biotype distribution. The study also observed increased virus symptom incidence in crops with higher whitefly densities, indicating the epidemiological importance of biotype composition in disease spread. These findings highlight the role of host plant diversity in shaping B. tabaci population structure and dynamics in vegetable ecosystems. Integrated pest management strategies incorporating crop diversification, resistant varieties, and vector monitoring are essential to suppress whitefly populations effectively. Overall, the study provides valuable insights into the ecological and molecular diversity of B. tabaci biotypes and their interaction with host plant diversity in mixed vegetable farming systems.