Epidemiology of Tomato Spotted Wilt Tospovirus in Bulgarian Tobacco Field

O. KARADJOVA1, D. HRISTOVA1 and G. ADAM2
1 Plant Protection Institute, BG-2230 Kostinbrod, Bulgaria
2 University of Hamburg, Germany

Abstract

KARADJOVA, O., D. HRISTOVA and G. ADAM, 2001. Epidemiology of Tomato Spotted Wilt Tospovirus in Bulgarian Tobacco Field. Bulg. J. Agric. Sci., 7: 583-594

An investigation was made of the tomato spotted wilt virus (TSWV) incidence in two Bulgarian tobacco-growing regions. The highest TSWV infection was found in tobacco (64.4 %) followed by tomato (12.5 %) and weeds (4.6%). Twelve weed species were found to be host plants of TSWV. The highest percentage of virus infection was established in Datura stramonium (43.75%) and in Galinsoga parviflora (40.48%). TSWV was also found in Solanum nigrum, Senecio vulgaris, Arthemisia absinthium and Cirsium arvense. The reproduction type and percentage of males of Th. tabaci was tested on 27 host plants. Arrhenotokous reproduction was established for 16 plant species, thelytokous in 9. The percentage of males was highest on Datura stramonium and Nicotiana tabacum (Solanaceae). In 1997 and 1998, an investigation was made of the seasonal population dynamics of Th. tabaci in a tobacco field. In both years, the percentage of males increased gradually during the vegetation of the crop, to reach its maximum at the end of the vegetation period in early September. A positive correlation was found between the increasing percentage of males in the population of Th. tabaci and their transmission efficiency. The highest virus infection (90%) on tobacco plants was established on 20 August, when the transmission efficiency of the tested individuals also was the highest-47.87%.

Key words: tomato spotted wilt virus, tobacco, weeds, arrhenotokous and thelytokous thrips populations