Identification of thrips infesting vegetable crops is the first and utmost important for healthy vegetable production. Morphological diagnostic keys have been established for accurate identification of thrips species to take timely management decisions to avoid crop losses. In the recent past with the advancement of molecular techniques, morphological identification is authenticated by molecular identification of insects including thrips. Molecular techniques have been found to be a contemporary tool for accurate identification and validation of species, phylogenetic relationships in insects, detection of cryptic species and invasive and alien species as compared to conventional morphometric taxonomy (Iftikhar et al. 2016). In order to save time, energy, expertise of scientific manpower and ease in identification of insect species, molecular tools are preferred over conventional taxonomy across the globe (Kadirvel et al. 2013). DNA based methods for species identification have advantages because they are technically simple, more accurate, applicable to large-scale screening, and do not require taxonomic expert (Hebert et al. 2003).
We have identified nine distinct species of thrips, T. palmi, S. dorsalis, T. florum, H. gowdeyi, B. melanocrnis, H. gangldaueri, F.schultzi, T. parvipsinus and T. hawaiiensis on three vegetable crops, brinjal, chilli and tomato. A total of seven species recorded from Chhattisgarh while six species from Madhya Pradesh. Very interestingly H. ganglbaueri, F. schultzei and T. parvispinus was exclusively recorded on chilli in Barauda, Raipur district of Chhattisgarh. While species, H. gowdeyi was also exclusively recorded on Chanti location of Jabalpur in Madhya Pradesh. However, Tyagi and Kumar (2013) reported seven distinct thrips species from Chhattisgarh for the first time of which six species namely F. schultzei, M. usitatus, T. florum, T. hawaiiensis, T. palmi and T. subnudula are injurious to crop plants. The present findings are in accordance with the above findings with regard to F. schultzei, T. florum, T. hawaiiensis, T. palmi indicating the existence of these species in Chhattisgarh. Then, S. dorasalis, T. palmi and B. melanicornis were reported from Madhya Pradesh (Tyagi and Kumar 2013). These species were also recorded from Tiwari Kheda and Pipariya locations of Jabalpur district of Madhya Pradesh in our study. Besides, they had also reported S. mangiferae, T. apicatus, T. subnudula on other host plants.
Invasive pests are one of the major threats in modern agriculture. Efficient management of invasive pests depends on its quick diagnosis, monitoring, and prediction of its current and future invading risks. Failure in any one of these results serious negative impact on crop production and native biodiversity (flora and fauna). One such example is the recent outbreak of invasive T. parvispinus Karny in south Indian states. The key morphological characters of T. parvispinus was ascertained with high-resolution scanning electron microscopic images, further MtCOI gene-specific primers was used for the molecular confirmation. Among the thrips species, T. parvispinus was exclusively recorded on chilli in Barauda, Raipur district of Chhattisgarh. T. parvispinus has already been documented as a pest in Carica papaya (Tyagi et al. 2015), Dahlia rosea (Rachana et al. 2018), Brugmansia sp. (Roselin et al. 2021) and chilli (Verghese 2021). H. ganglbaueri is a pest of millets. It is one of the most widely distributed species in the genus Haplothrips and specimens have been studied across much of the Palaeotropics, from Iran to Timor-Leste, Australia and India (Minaei and Mound, 2008; Sridhar et al. 2022). There is variation across the distribution, such that individuals from Iran often have the mid and hind tarsi almost yellow, whereas in specimens from Australia these tarsi are brown. In this study, H. ganglbaueri, was recorded 4.8% population (6 nos), and it was exclusively recorded on chilli in Barauda, Raipur district of Chhattisgarh. H. gowdeyi is found widely around the world in tropical and subtropical countries. H. gowdeyi was exclusively recorded in Chanti of Jabalpur with 1.6% population (2 nos).
A total of 89 morphospecies have been reported from India of which 14 was detected by molecular operational taxonomic units, (MOTU’s) using species delimitation methods (Tyagi et al. 2017). Thrips species diversity also varies across locations as well as host plants. According to Rachna and Varadarajan (2017) consolidated systematic list of 333 species of terebrantian thrips, belonging to 118 genera recorded so far from India across the host plants and over space and time. Sanjta and Chauhan (2015) have reported more than ten species, T. tabaci, T. flavus, T. palmi, T. carthami, T. alatus, Ayyaria chaetophora, Anaphothrips sudanensis, S. dorsalis, M. peculiaris, Neohydatothrips samayankur, Aeolothrips sp., H. tenuipennis from different vegetable crops in Himachal Pradesh. T. tabaci, T. flavus and T. palmi were recorded as polyphagous pests on onion, capsicum, coriander, broccoli, pea, tomato, radish, fenugreek, brinjal, cucumber, bean, kale and mustard. The global status of thrips species occurring on vegetables, at least 14 species of thrips viz., Thrips tabaci Lindeman, T. palmi, T. setosus, S. dorsalis, Frankliniella occidentalis, F. schultzei, F. bispinos, F. cephalica, F. fusca, F. gemina, F. intonsa, F. zucchini, Ceratothripoides claratris, and Dictyothrips betae were reported to occur and transmit various types of tospoviruses across the globe (Kadirvel et al. 2013).
Among nine, four species S. dorsalis, T. palmi, T. arvispinus and F. schulzei were found to be vectors of Groundnut bud necrosis virus, Tobacco streak virus, Groundnut ringspot virus, Tomato spotted wilt virus etc in India as well as in the world indicating the seriousness of the direct and indirect damage caused by these thrips species in vegetables crops in central India (Supplementary table).