HOST STATUS OF SEVERAL CUT FLOWER CROPS TO THE ROOT-KNOT NEMATODE, MELOIDOGYNE INCOGNITA

Abstract

Many cut flower growers in Florida produce crops directly in the field, subjecting them to soilborne diseases and root-knot nematode infection. Seven cultivars of cut flowers were tested for their susceptibility to two races of the southern root-knot nematode (Meloidogyne incognita) in a greenhouse. Cultivars evaluated were 'Potomac Royal' snapdragon (Antirrhinum majus), 'Madonna Blue' blue lace flower (Didiscus caeruleus), 'Green Mist' and 'Queen of Africa' white dill (Ammi majus), 'Qis White Cut' larkspur ( Consolida ajacis), and 'Avila Rose Rim' and 'Echo Pink' lisianthus (Eustoma grandiflorum). Cultivars of lisianthus and larkspur tested were relatively poor hosts to M. incognita races 1 and 2 as compared to the known susceptible host, snapdragon (P 0.05). Based on number of nematodes extracted per gram of root tissue, 'Madonna Blue' blue lace flower was more susceptible, 'Green Mist' white dill was equally susceptible, and 'Queen of Africa' white dill was less susceptible than snapdragon (P 0.05). Numbers of nematodes per gram of root were not different for M. incognita races 1 and 2 (P 0.05) on any plant cultivar. Despite differences in nematode susceptibility, numbers of flowers, and shoot and root weights of all cultivars tested except 'Madonna Blue' were not affected by nematode inoculation. Meloidogyne incognita race 1 reduced the number of flower buds and shoot weight of 'Madonna Blue' compared to the control, indicating that this blue lace flower cultivar is intolerant to this nematode.