ABSTRACT
OBJECTIVE: To develop a gas chromatography (GC) method for determination of chlorfenapyr in flower buds of Lonicera japonica Thunb, and study the degradation dynamics of chlorfenapyr in honeysuckle collected through field experiment, thus providing theoretical references for the application of chlorfenapyr in practical production of honeysuckle. METHODS: Honeysuckle samples were extracted with acetone using a vortex mixer and then cleaned up by passing through a neutral alumina chromatography column, followed by detection by gas chromatography with electronic capture detector (GC-ECD). External standard method was used for quantification. RESULTS: At fortified levels of 0.02-0.5 mg•kg-1, the average recoveries of chlorfenapyr in honeysuckle were from 83.9% to 97.6%, with RSDs of 0.6%-9.2%. The limit of detection was estimated to be 7.3 μg•kg-1. The degradation dynamics of chlorfenapyr in honeysuckle conformed to first-order dynamic equation. The degradation half-life of chlorfenapyr was 2.3 d. CONCLUSION: The method developed in this experiment is simple, rapid, reliable and in line with the requirements of pesticide residue analysis. The degradation rate of chlorfenapyr in honeysuckle is relatively rapid. Chlorfenapyr belongs to pesticides which are liable to degradation.
ABSTRACT
The study was aimed to determine the efficacy of two pesticides in the control of aphids in Lonicera japonica, and study the applicability of pesticides in L. japonica. The number of insects was counted before and 2, 3, 7 and 10 days after the application of pesticide in the test area within different dosage groups. The method was 5-point sampling method. Five aphids on the L. japonica branches were selected, then the number of insects was recorded. The effect of the two pesticides on the control rate of aphid was more than 80% at 1 d after application. The results showed that the two pesticides had good efficacy. After 7 days and 10 days, the control effect was 100%. After 1 day of spraying, the effect of the two pesticides on the control of L. japonica aphids was more than 80%, which was higher than that of the control agent. The results showed that the two pesticides had good and fast effect. After 7 days and 10 days of spraying, the control effect was 100%. The control effect of two kinds pesticides for aphid sprayed in recommended dose on the L. japonica is good and showed no hytotoxicity.