Host-specific development of Thrips parvispinus (Karny) (Thysanoptera: Thripidae): demography, phylogeny, and biological control prospects in India

• Published in: Phytoparasitica 2024-11, Vol.52 (5), p.86-86, Article 86
• Main Authors: Keerthi, M. C., Prasannakumar, N. R., Sridhar, V., Manjunatha, C., Mounika, A.
• Format: Article
• Language: English
• Subjects: Agriculture; Biological control; biological control agents; Biology; Biomedical and Life Sciences; Cladosporium; Conidia; Cytochrome-c oxidase; Demography; Developmental stages; Ecology; egg incubation; entomopathogens; environmental impact; extrusion; Extrusion cladding; Gene sequencing; genes; Genetic analysis; genetic variation; Host specificity; India; Insecticides; Life Sciences; oxidoreductases; Parameter identification; Pathogens; Pest control; Pests; Phylogeny; Plant Pathology; Plant Sciences; Population; Population genetics; Population growth; Population studies; South East Asia; Spraying; Survival; survival rate; Thrips parvispinus
• ISSN: 0334-2123; 1876-7184
• DOI: 10.1007/s12600-024-01207-w

Thrips parvispinus (Karny) is a significant polyphagous pest native to Southeast Asia. It invaded India in 2015, causing substantial economic damage to chilli. The farmers resort to the indiscriminate spraying to manage the pest. Despite the thrips invasion in 2015, the biology and demography of T. parvispinus were not recorded in India, which is crucial for identifying weak stages for successful management. The present study aims to understand the biology and life-table parameters of T. parvispinus on chilli and capsicum and explore the potential of entomopathogens as biological control agents under laboratory conditions. The identity of T. parvispinus was confirmed through morphological keys and molecular sequencing of the Cytochrome c oxidase subunit I (COI) gene (GenBank No: OR366449.1). The phylogenetic analysis revealed that the study population was identical to the original resident population, and there is no genetic divergence in the sequences compared. The T. parvispinus had the shortest developmental duration on chilli, with an egg incubation period of 4.57 days and a total life cycle of 25.07 days, compared to 27.64 days on capsicum. The intrinsic rate of increase ( r ) was higher on chilli (0.13) than on capsicum (0.11), indicating a faster population growth in chilli. The T. parvispinus population doubles every 5.17 days on chilli and every 6.46 days on capsicum. Interestingly, pre-pupa have the lowest survival rate on chilli (0.65) and capsicum (0.6). The Cladosporium spp. was identified (GenBank No: PQ106983) as a potential biocontrol agent, causing significant mortality in T. parvispinus populations (69.10% at 1 × 10 8 conidia/mL). The ditrophic interaction was studied through SEM imaging, showing that at 72 hpi, multiple points of penetration from a germinating conidium were observed, and at 120 hpi, extrusion was noticed from the oral opening. The findings suggest that targeting the vulnerable immature stages of T. parvispinus and integrating entomopathogens like Cladosporium spp. could enhance sustainable pest management strategies, reducing reliance on synthetic insecticides and mitigating their ecological impact.