Abstract
Tomato plants were susceptible to infection by tomato leaf-curl virus (TLCV) at all stages of their growth. The incidence of TLCV in some tomato growing areas of Kamataka, India, ranged 17-53% in July-November to 100% in crops grown in February-May (summer). In sequential sowings, 90-100% of plants were infected in plots sown between the end of January and end of May. Infection in plots sown later was progressively less. 50-70% yield loss was observed in tomato cv. Pusa Ruby sown in February-May. A strong correlation was obtained between the percentage incidence of TLCV and whitefly (Bemisia tabaci) numbers (r = + 0.970, P = 0.01). TLCV was transmitted by B. tabaci to 23 host plants. B. tabaci was observed in nature on 173 plant species around Bangalore. Five lines of Lycopersicon hirsutum Hamb. & Bonpl. (Pl 390513, Pl 390658, Pl 390659, LA 386, LA 1777) and two lines of L. peruvianum Mill. (Pl 127830, Pl 127831) were resistant to TLCV. Covering the tomato seedling nursery with nylon net for 25-30 days, together with application of four sprays of monocrotophos (Nuvacron) at 10-day intervals after transplanting delayed the spread of TLCV for 3-5 weeks and increased tomato yields.
