~ 84 ~ Journal of Entomology and Zoology Studies 2020; 8(1): 84-90 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2020; 8(1): 84-90 © 2020 JEZS Received: 16-11-2019 Accepted: 18-12-2019 Sachin US Department of Entomology, College of Horticulture, Bagalkot, Karnataka, India Venkateshalu B Department of Entomology, College of Horticulture, Bagalkot, Karnataka, India Fakrudin B Department of Biotechnology and Crop Improvement, College of Horticulture, Bengaluru, Karnataka, India Kotikal YK Director of Extension, University of Horticultural Sciences, Bagalkot, Karnataka, India Raghavendra K Mesta Department of Plant Pathology, College of Horticulture, Bagalkot, Karnataka, India Hadimani HP Department of Vegetable Science, College of Horticulture, Bagalkot, Karnataka, India Raghavendra S College of Horticulture, Bagalkot, Karnataka, India Corresponding Author: Sachin US Department of Entomology, College of Horticulture, Bagalkot, Karnataka, India Morphometric analysis of whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) puparia from different agroclimatic zones of Karnataka, India Sachin US, Venkateshalu B, Fakrudin B, Kotikal YK, Raghavendra K Mesta, Hadimani HP and Raghavendra S Abstract Being an polyphagous pest of many agricultural and horticultural crops, whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) place an important role as a vector for transmission of more than 111 plant viruses which affects the crop development. B. tabaci is having 36 morphologically indistinguishable genetic groups. In the present study detailed survey was undertaken to collect B. tabaci puparia samples from eleven districts of Karnataka which were distributed in seven agro climatic zones during the year 2016-17. The morphometrics of B. tabaci puparia was recorded for 12 different characters and has recorded significantly higher values for 9 out of 12 characters in Dharwad population. The combined cluster analysis of B. tabaci puparia revealed the existence of two major clusters-Cluster 1 and Cluster 2 on which populations from different locations were distributed. The principal component analysis (PCA) based on morphometrics of puparia disseminate that, the first three principal components (PCs) account for 98.417 per cent of total variation. The morphometrics reveal that there are distinct variations which could be explored for morphological delineation of genetic groups/ putative species of B. tabaci. Keywords: Bemisia tabaci, genetic groups, agro-ecological zones, morphometry, principal component analysis 1. Introduction Whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a haplodiploid, inconspicuous insect, well known for causing damage to plants either by direct or indirect way. Directly by feeding on plant sap and indirectly by transmitting viral diseases. In addition, they excrete honey dew which deposits on the surface of plant leads to the formation of sooty mould (e.g., Capnodium spp.) on the top of the leaves which adversely affects the photosynthesis and respiration in the plant. It is a polyphagous pest, reported on more than 900 host’s plants and reported to transfer more than 111 plant viruses as a vector [7] . It has become a serious pest in numerous agricultural, horticultural and other commodity crops [11, 23] . Being a cryptic species complex, Bemisia tabaci consisting of 24 morphologically indistinguishable species and which are placed under 11 well-defined high-level groups [4] . B. tabaci as a complex species and variation among the population exists in different tomato growing areas because of its polyphagous nature. With reference to systematics or taxonomy, morphology is considered as the top-tier basis for species separation [6, 30] . The taxonomic identification of B. tabaci is based on the morphology of the fourth larval instar, 'puparia' [15] . But some studies had shown that, these might vary within the species [6, 17, 25] . These phenotypic variations are largely determined by the host leaf morphology [20] and other factors. Such phenotypic plasticity has led to confusion in recognition of its populations/genetic groups/putative species established through other studies. This has also led to redescriptions and synonymization [4, 19] . Thus the morphologically indistinguishable or indistinct populations had been designated as biotypes/genetic groups/putative species. Many studies which propose new genetic groups/putative species and distinction of these in the B. tabaci species complex had been largely through non morphological definitions. Thus there is an impending need to analyze their morphological variations and document them, so as to enable differentiating them and if possible provide a