Field incidence and analysis of biology and morphometrics of the invasive spiralling whitefly, Aleurodicus dispersus (Hemiptera: Aleyrodidae), in cotton in Tamil Nadu, India.

The incidence of Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae) was surveyed in production fields of cotton, Gossypium hirsutum L., in Tamil Nadu, India, from December 2021 to April 2022. Plants sampled in the crops were winter and summer planted, 45–95 days past seeding, and in the flowering to boll development stages. Whitefly counts from the sampling yielded a range of 4.4 to 8.9 adults and nymphs per 3 leaves (sample unit). The nymphs and adults collected from the fields were taxonomically confirmed using taxonomic characteristics obtained by photographs of live and slide-mounted specimens. Identification was further confirmed by molecular techniques using the mitochondrial Cytochrome Oxidase subunit I gene (COI) universal primer-based polymerase chain reaction (PCR) amplification and sequencing. The resulting dendrogram, constructed using MEGA-X and analyzed using the maximum likelihood method, yielded a single clade with sub-lineages of the specimens collected in this survey. Overall, the mean (± SD) duration of the entire life cycle of A. dispersus collected was 43.9 ± 2.4 d. Mean (± SD) length x width the developmental stages were 283.8 ± 13.3 μm x 167.0 ± 4.5 μm for eggs, 335.7 ± 19.3 μm x 266.9 ± 25.7 μm for first instars, 473.8 ± 21.6 μm x 349.8 ± 21.3 μm for second instars, 774.4 ± 15.11 μm x 440.2 ± 5.8 μm for third instars, 881.1 ± 16.7 μm x 634.7 ± 5.2 μm for fourth instars, and 970.0 ± 9.1 μm x 836.9 ± 12.7 μm for adults. [ABSTRACT FROM AUTHOR]