Biology of Scirtothrips dorsalis (Hood) (Thripidae: Thysanoptera) on Citrus in Punjab, India

Scirtothrips dorsalis (Hood) is a citrus pest that affects nursery growth and fruit quality. This study examined its developmental and reproductive characteristics on citrus under laboratory conditions at Punjab Agricultural University, Ludhiana, India, during 2022–2024. Adults collected from citrus plants were reared on fresh citrus leaves, and biological parameters were recorded across successive generations. Egg incubation lasted 3–7 days, with a mean of 5.04 ± 0.22 days. The first and second nymphal instars lasted 2–7 days (4.27 ± 0.24 days) and 3–6 days (4.34 ± 0.21 days), respectively, while the total nymphal period ranged from 5 to 12 days (8.61 ± 0.38 days). The prepupal and pupal stages each lasted 1–3 days, with mean durations of 1.32 ± 0.20 and 1.42 ± 0.23 days, respectively. Adult female longevity ranged from 6 to 12 days (8.03 ± 0.23 days). The reported total developmental period was 17–33 days (24.42 ± 0.57 days). Fecundity-cum-viability ranged from 4 to 24 viable nymphs per female, with a mean of 9.91 ± 0.23. Nine successive generations were recorded during the study period, with variation in developmental duration and stage-specific survival among generations. These findings document the biology of S. dorsalis on citrus under the conditions investigated and provide baseline observations for subsequent studies of its population development.