Effects of three Fusarium spp. on the growth of lentil in Huining County, Gansu Province

Lentil is one of the widely planted crops in the center areas of Gansu Province as economic, rotation and soil-fertilized plant. However, death of lentil is very serious in Huining County in recent years. The field investigation, isolation and identification of causal agent were conducted to determine the reasons of plant death. In 2012, incidence of lentil root rot was 58.4%, and mortality was 43.2%. Fungi isolated from the roots of diseased plants were morphologically identified as Fusarium oxysporum, F. acuminatum and F. equiseti, which were consistent with the phylogenetic tree based on ITS sequence. Isolation frequency of these fungi was 55%, 18% and 9%, respectively. In the inoculation experiment, the root length and root dry weight of host inoculated with all 3 fungi significantly (P0.05) decreased in which the host with F. oxysporum decreased most and the host with F. equiseti decreased more. The fresh weight and plant height of host inoculated with F. oxysporum and F. equiseti also decreased. However, the emergence and survival rates of host inoculated with all 3 fungi were not affect (P0.05). The soils were collected from lentils fields in Huining as plants growth medium. Compared with plants grown in autoclaved soil, root length and root dry weight of plant grown in no-autoclaved soil significantly (P0.05) decreased. In conclusion, 3 Fusarium species were weak pathogenic to lentils. Drought possible was the main reason for these Fusarium species causing serious death on lentils.