Evaluation of non-host crops as trap crops to reduce Orobanche seed bank in tomato fields

Orobanche species, commonly known as broomrape, are root holo-parasite of the family Orobanchaceae.  In Nepal two species, Orobanche aegyptiaca and O. cernua are causing threat to wide range of important vegetables and crops of family Brassicaceae and Solanaceae. To evaluate non-host plants as potential trap crops, different crop plants were tested in two Orobanche infested tomato fields of Lalbandi, Sarlahi, South-Eastern part of Nepal in 2018 -19. Orobanche seed density in soil samples collected from plots before planting and after harvest of each crop species were recorded and compared for the seed bank. On the basis of Orobanche seed bank reduction in both the fields, the investigated crop species like Capsicum frutescens, Cicer arietinum, Lens culinaris and Vicia faba were classified as highly potential trap crops and reduced seed bank from 52 to 70%. Crops like Cuminum cyminum, Daucus carota, Foeniculum vulgare, Phaseolus vulgaris, Sessamum orientale and Trigonella foenum-graecum were classified as moderately potential trap crops and reduced Orobanche seed bank from 41 to 52 %. The other tested crops like Allium cepa, Allium sativum, Coriandrum sativum, Glycine max, Hordeum vulgare, Pisum sativum, Solanum tuberosum, Raphanus sativus are classified as non- potential trap crops. Among all the tested crops Capsicum frutescens, Cicer arietinum, Lens culinaris and Vicia faba were identified as the potential trap crop to reduce Orobanche seed bank in infested tomato fields.