Investigation of mortality rate of alfalfa stem nematode Ditylenchus dipsaci under the influence of saponins of some alfalfa ecotypes (Medicago sativa)

Alfalfa stem nematode (Ditylenchus dipsaci) is one of the most important and destructive pests of economic crops such as alfalfa, garlic, onion and tulip. The effects of Saponins from the aerial parts of six alfalfa ecotypes on the mortality of alfalfa stem nematode was investigated under laboratory conditions. In this study. The results showed that among the crude Saponin treatments, the amount of 90 microliters from the Hamedani and Faiz ecotypes had the highest effect with 96% and the amount of 50 microliters from the local Miandoab ecotype 42% had the least effect on the nematode mortality. Also, among the pure Saponins, the amount of 50 microliters of Hamedani, Shiraz–Plycross and Faiz ecotypes with 99%, and the amount of 10 microliters of Nishaburi ecotype with 68% had the highest and lowest effect, respectively, on the mortality of the nematode. In most ecotypes, increasing the concentrations of crude Saponin from 50 to 90 microliters and pure Saponin from 10 to 50 microliters causing 54% and 31% mortalities led to an increase in nematode mortality. It means there is a positive correlation between alfalfa stem nematode mortality and the raw and pure Saponin concentration of alfalfa ecotypes. Subsequently, Hamedani, Faiz and Polycross Shiraz ecotypes showed the highest effect and Miandoab and Nishaburi local ecotypes showed the least effect on the mortality of this nematode. .