Studies On The Nematocidal Activities Of Harmaline Derivatives

Plant-parasitic nematodes are one of the main pathogens of plants. Botanical pesticides are important objects of our research and development of new pesticides. Peganum harmala L. has a kind of ?-carbolines with a variety of biologically active compounds. In this thesis, 19 kinds of harmaline derivatives were tested against mixed instar of Bursaphelenchus xylophilus and second instar larvae of Meloigune incognita. The nematocidal activities of the main active ingredients were studies on B. xylophilus and M. incognite for looking for new nematicide.The bioactivity against B. xylophilus and M. incognite of 19 kinds of harmaline derivatives were determined. The results of contact activities to B. xylophilus treated by 200 ug/m L of synthesised compounds showed positive nematicidal activities. There are four kinds of compounds with highest activity. After 72 h treatment, the corrected mortalities of synthesised compounds e ? o ? p and r were greater than 80%, and compounds e and p against B. xylophilus were 90.88% and 92.69%. The results showed that these two compounds on killing activity of B. xylophilus especially prominent, after 24 h?48 h and 72 h treatment, the corrected mortalities were 49.90%, 66.79%, 90.88% and 49.03%,77.29%, 92.69%, and the toxicity activities were higher than HL(82.49%), and significantly higher than the other tested compounds.The results of contact activities to M. incognite treated by 200 ug/m L of synthesised compounds showed positive nematicidal activities. There are three kinds of compounds with highest activity. After 72 h treatment, the corrected mortalities of synthesised compounds j?n and p were greater than 80%, and compounds p and j against M. incognite were 93.16% and 91.25%, and the toxicity activities were higher than HL(60.38%). Test results showed that these two compounds on killing activity of pine wood nematode in particular, after 24 h?48 h and 72 h treatment, nematode-trapping mortality rates were 49.56%, 72.22%, and 93.16%, 76.75%, 91.25%, and the toxicity activities were higher than HL(82.49%), and significantly higher than the other compounds tested. The results showed that these two compounds on toxicity activities of M. incognite especially prominent, after 24 h?48 h and 72 h treatment, the corrected mortalities were 49.56%, 72.22%, 93.16% and 44.07%,76.75%, 91.25%, the toxicity activities were higher than HL(82.49%), and significantly higher than the other tested compounds.The effects of P.harmala on the development of root-knot nematode. The results showed that larva hating of M. incognita could be significantly inhibited by compounds j?n and p.The results of pot test revealed that P.harmala could effectively control the pine wood nematode disease caused by B. xylophilus and the water spinach root-knot disease caused by M. incognita.The results of pine wood hydroponic experiment showed that compounds e, o, p, r could delay the development of pine wilt disease and protect pine wood. Pine diease developed slowly after treatment by compounds o and p. After 12 d treatment, the illness index of synthesised compounds e?o and p were 0.25 while control's was 0.83. Harmaline derivatives and ck processings did not stop the flow of fat after 9 d treatment, but a significant reduction or even stop in pine flow fat amount of " ck + B. xylophilus " treatment, and the average flow fat amount was 4.67 ± 0.33.The results of water spinach pot test showed that compounds j?n?p could effectively control the water spinach root-knot disease caused by M. incognita. Compared with ck, they can promote the growth of aerial parts and root-knot decrease significantly. The numbers of root knot after compound treatment and disease stages were significantly lower than ck, and the difference between to contrast agents abamectin treatment is not obvious.