Indian Journal of Entomology Online published Ref. No. e23840 DoI. No.: 10.55446/IJE.2023.840 INCIDENCE OF ONION THRIPS THRIPS TABACI LINDEMAN IN SOME CABBAGE VARIETIES IN KOSOVO Saranda MuSa 1,2 and Fadil MuSa 2 * 1 Department of Entomology, Institute of Plant Protection, Hungarian University of Agriculture and Life Sciences, 44 Ménesi Street, H-1118 Budapest, Hungary 2 Department of Plant Protection, Faculty of Agriculture and Veterinary, University of Prishtina, Boulevard “Bill Clinton”p.n. 10 000 Prishtina, Kosova *Email: fadil.musa@uni-pr.edu (corresponding author): ORCID ID: 0000-0002-7276-9308 ABSTRACT Onion thrips (Thrips tabaci Lindeman) is a serious pest of cabbage worldwide. This study assesses the distribution of this thrips in three cabbage varieties (Proctor, Partula, and Atria) cultivated in open felds in three localities of Kosova (Barilevë, Prishtinë, and Podujevë). The experiment was conducted during 2020 and 2021 in randomized Fisher blocks design with four replications. Observations on the incidence of thrips confrmed with yellow sticky traps measuring 15x 20 cm revealed statistically signifcant differences with regard to years, localities, and varieties. This study reveals for the frst time, the occurrence of T. tabaci on cabbage varieties cultivated in Kosovo. Key words: Thrips tabaci, cabbage varieties, Atria, Partula, Proctor, incidence, ANOVA, number of thrips, yellow sticky traps, population buildup, variation Onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a worldwide distributed insect pest of economic importance (Diaz Montano et al., 2011; Fail, 2016). Direct feeding causes economic damage to over 300 host plant species, causing U.S. $1 billion in crop losses (Balan et al., 2018). Besides causing direct damage, this pest has been known as a vector of two economically signifcant viral pathogenes, tomato spotted wilt virus (TSWV), and Iris yellow spot virus (IYSV). It is estimated that IYSW causes annual losses of U.S. $90 million to onion production in the western USA alone (Gent et al., 2006), whereas TSWV can cause over U.S $1 billion in crop losses annually worldwide (Goldbach and Peters, 1995). Onion thrips damage the white cabbage (Brassica oleracea L.) outdoors (Wolfenbarger and Hibbs, 1958) and in storage as well (Fox and Delbridge, 1977). Damage can appear as a bronze discoloration and/ or a rough texture on leaves within heads (Shelton and North, 1986), causing injury up to 20 layers deep (Trdan et al., 2005) and reducing marketable yield. The use of insecticides usually results in poor control of onion thrips on cabbage (Andaloro et al., 1983), and a high amount of insecticides is required because of their high escape capacity, fast development rate, and low sensitivity to the insecticides. On the other hand, few studies have been carried out to evaluate the patterns of resistance of cabbage varieties against onion thrips. Three different mechanisms of plant resistance to insects have been defned 1) non-preference (antixenosis), 2) antibiosis, and 3) tolerance (Painter, 1941). Based on the number of thrips colonizing the cabbage heads, Fail et al. (2008) reported that only some varieties possess antixenotic resistance. Despite several studies, the resistance mechanisms of cabbage to onion thrips remains unknown (Shelton et al., 2008). Taking into consideration the fact that T. tabaci is a serious threat to cabbage production worldwide (Shelton et al., 1983; Giessmann, 1988; Kristof and Penzes, 1984; Kahrer, 1992; Herold and Stengel, 1993; Ellis et al., 1994), the main goal of this work was to assess its buildup and population dynamics in three cabbage varieties grown in open felds in the three localities of Kosova during two cropping seasons (2020–2021). MATERIALS AND METHODS Field surveys for T. tabaci infesting cabbage in the three most important localities of cabbage production in Kosovo (Prishtinë, Barilevë, and Podujevë) were undertaken in the 2020-2021 growing season. The felds were situated in Prishtinë (42°6882’, 21°1466’, 603 masl), Podujevë (42°8322’, 21°2081’, 636 masl) and Barilevë (42°7518’, 21°1210’, 526 masl). Three varieties of cabbage (Proctor, Partula, and Atria) were included, and these were grown under insecticide-free conditions. In May, cabbage seeds were sown in pro