| Botanical-derivated VFB was a new kind of anti-viral pesticide which was developed byResearch and Development Center of Biorational Pesticide, Northwest A&F University.Portulacaoleracea L. is the main processing material of VFB. Preliminary researchesindicated that VFB played an important role in prevention and treatment against various virusdiseases. It had a broad prospect of application. At present, although the basic procressingtechnic was explicit, there were some questions both its high cost and some unclear indexes ofthe procressing technic to be solved, the further optimization on procressing technic had to becarried out.Based on the above problems, we firstly optimized the procressing technic on the basicformula of VFB, then carried out field trials. There were some results we got as the following:(1) The combination of different adjuvants had a different influence on the activity ofVFB, some combination inhibited the activity of VFB. The result showed that the adjuvant A,which was4%in composition, should be retained as the main adjuvant of VFB.(2) Some indexes including the extraction time of plant material, extraction times, theratio between solvent and plant material were not explicit. Through the unifactor experimentand the orthogonal test, the better extraction technic is: the extraction time20h, the extractiontimes5times, the ratio between solvent and plant material9:1.(3) The influence of some kind of surfactant to VFB activity was similar. The activity ofVFB had a significantly improvement after mixed5%OP-10and1%APG into plant extract.(4) The activity of OP-VFB had a great improvement on TMV inactivated in vitro,inhibiting TMV infection and inhibiting the multiplication of TMV. In the experiment of theTMV inactivated in vitro,50times the dosage, mixing OP-VFB with TMV for5min, theinhibition rate were83.33%and88.00%, increased by39.33%and48.80%respectively; Inthe experiment of inhibiting TMV infection,50times the dosage,6h interval betweenOP-VFB application and TMV inoculation, the inhibition rate were74.20%and77.15%,increased by20.20%and26.50%respectively; In the experiment of inhibiting themultiplication of TMV,50times the dosage,6h interval between TMV inoculation andOP-VFB application, the inhibition rate were66.67%and69.00%, increased by29.34%and 29.60%respectively. It performed noticeably comparing with Moroxydine+Cupricacetate,W.P.(20%).(5) Pot experiment of OP-VFB againt TMV showed that OP-VFB was superior to thecontrast pesticide both in preventive test and in treatment test. Futhermore, the preventive testwas significantly higher than the treatment.(6) In the field plot trials of OP-VFB againt TMV, the experiment results indicated thatthe three different spraying ways of the100times of OP-VFB were better thanMoroxydine+Cupric acetate, W.P.(20%). For these field plot trials, OP-VFB(100times,spraying+pouring) had the best inhibition rate. |
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