Nangjing Forestry University, Nanjing 210037, P. R. China.
Nematicidal activity of aloperine, cytisine, N-methylcytisine and matrine was bioassayed by the agar medium method and the cotton ball method. The corresponding results from the two methods showed that the nematicidal activity of aloperine was the strongest. Its activity, expressed log (1/ID50) was also the strongest (8.67) in comparison to the previously reported nematicidal activity of seven other quinolizidine alkaloids bioassayed by the same method. It is hypothesized that the nematicidal activity of quinolizidine alkaloids is determined primarily by the types of functional group pairs and types of functional group in their molecular structures. Based on the hypothesis, the alkaloids with strong nematicidal activity were predicted on the basis of their structure. Field tests were done with an aloperine formulation in Najing, P.R. China. 0.042, 0.124g of aloperine was injected into the basal trunk of 6-7 years old health blak pine, Pinus thunbergii, in late June. One and two weeks before the injection, an inoculation was received by each treated pine tree with pine wood nematodes, Buesaphelenchus xylophilus. Results were cheked in the late March of the following year by growth of the new lead shoots. The survival rates of treated and control trees were 50%, 93.8% and 20% respectively. Aloperine is the first natural compound the effects of which in control of pine wilt disease have been confirmed in field tests. The feasibility to use the aloperine formulation in control pine wilt disease was discussed.