Research On Insecticidal Technology Of The Cantharidin And Its Derivatives

Cantharidin（C10H12O4）is an important natural defenses product and widely exsists in themeloid insects （Meloidae）. Because of its good therapeutic effect upon antitumor, Cantharidinhas been widely used in the tradical medical science. It was also reported that it has toxicityactivities against some pests、plant pathogenic and herbicidal activities. It would play animportant role in agriculture area.The application trial of1.0%Cantharidin EC and Norcantharidin in5%ME wereconducted to confirm the control effect on Plutella Xylostella. Cantharidin EC andNorcantharidin ME are prepared in our laboratory, and both laboratory assay and fieldexperiment are carried through to develop practical methods to control Plutella xylostellausing cantharidin EC and Norcantharidin ME.The main results are as follows:1. The laboratory assay of Cantharidin EC to Plutella XylostellaThe results showed that in laboratory tests,1.0%Cantharidin EC LC₅₀against Plutellaxylostella after24h were22.306mg/L. And in different temperatures and light intensity, theLC₅₀（24h） change is very small. At15℃,20℃and25℃temperature for LC₅₀（24h） againstPlutella xylostella were22.904mg/L,19.390mg/L and22.916mg/L. In light intensity of1,2and3, the LC₅₀（24h） were19.39mg/L,22.16mg/L and19.60mg/L. Experimental resultsshowed that1.0%Cantharidin EC has good stability, its insecticidal activity is not affected bythe light and temperature.2. The laboratory assay of5.0%Norcantharidin ME to Plutella XylostellaThe results showed that in laboratory tests,1.0%Cantharidin EC LC₅₀against Plutellaxylostella after24h were81.51mg/L. And in different temperatures and light intensity, theLC₅₀（24h） change is very small. At15℃,20℃and25℃temperature for LC₅₀（24h） againstxylostella were90.253mg/L,91.377mg/L and95.743mg/L. In light intensity of1,2and3, theLC₅₀（24h） were81.5mg/L,93.24mg/L and81.963mg/L. Experimental results showed that5.0%Norcantharidin ME has good stability, its insecticidal activity also is not affected by thelight and temperature.3. Field experiment of Cantharidin EC to Plutella Xylostella The field efficacy trial of1.0%Cantharidin EC showed that the efficacy of1.0%Cantharidin EC at27.78g a.i./hm²³7g a.i./hm²respectively against Plutella Xylostella on the7th day after treatment, the efficacy can achieve90%above; Spraying1.0%Cantharidin EC27.78g a.i./hm²in different instar, the optimum application time was the outbreak period ofthe first instar. The efficacy of against Plutella Xylostella can achieve90.21%after7th daytreatment. In the Plutella Xylostella hazard peak, spraying the1%Cantharidin EC27.78ga.i./hm²once, compared with spraying twice and spraying three time, there was no significantdifference.4. Field experiment of Norcantharidin ME to Plutella XylostellaThe field efficacy trial of Norcantharidin in5%ME showed that the efficacy ofNorcantharidin in5%ME at111.11g a.i./hm²¹38.89g a.i./hm²respectively against PlutellaXylostella on the7th day after treatment, the efficacy can achieve90%above; Spraying5%Norcantharidin ME111.11g a.i./hm²in different instar, the optimum application time was theoutbreak period of the first instar. The efficacy of against Plutella xylostella can achieve90.96%after7th day treatment. spraying the5%Norcantharidin ME twice, the efficacy ofagainst Plutella xylostella can achieve90%after7th day, achieve the prevention Plutellaxylostella...