UTTAR PRADESH JOURNAL OF ZOOLOGY

Microcephalothrips abdominalis (Crawford), known as composite thrips, is a neotropical species now established in various regions including India, parts of Europeand the US, where it infests crops like marigold,beansand Asteraceae family plants. Severe infestations cause significant damage, such as leaf bronzing, pod quality reduction, petal discolorationand hindered seed development, significantly lowering market value. Additionally, it vectors Tobacco streak virus (TSV) to weeds and crops, amplifying economic losses in floriculture and vegetable production. The bio-ecology of Microcephalothrips abdominalis (Crawford)was investigated on marigold leaves (var. Benztall) under controlled laboratory conditions at the College of Horticulture (COH), Bengaluru, from January to February 2021. Experiment was maintained at 26 ± 2°C temperature and 70 ± 5% relative humidity. Thrips collected from field-infested marigold plants were identified as M. abdominalis through morphological traitsviz., small head narrower than prothorax, seven antennal segments (3rd/4th light-colored), fringed brown wings and sexual dimorphism. The results indicate that the total life cycle averaged 16.98 ± 3.07 days, comprising egg (1.95 ± 0.41 days; bean-shaped, whitish, inserted in lower leaf surfaces), first instar larva (2.60 ± 0.41 days; tiny/whitish, 0.54 ± 0.01 mm), second instar (3.98 ± 0.97 days; yellowish, 0.82 ± 0.01 mm), pre-pupa (1.38 ± 0.53 days; dark/sluggish, upward antennae), pupa (1.97 ± 0.29 days; folded antennae, full wing pads)and adult (5.10 ± 0.46 days; male: 0.96 ± 0.04 mm, female: 1.13 ± 0.04 mm).Observations used Petri dishes with fresh leaf arenas, 40 × 40 × 40 cm cages (10 adults/plant)and 8-hour stereo microscopy for exuvial confirmation, enabling precise stage delineation.