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| Effect of Tea Leafhopper on the Biochemical Components of Tea and Control Effect of High-efficiency Low Water-soluble Pesticides |
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| DOI：10.16768/j.issn.1004-874X.2020.09.012 |
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| Abstract: |
| 【Objective】The control effects of three low water-soluble pesticides on tea leafhoppers were tested, and the effects of tea leafhoppers on the biochemical components of tea during different damage periods were analyzed so as to provide a basis for taking strong picking measures in a timely manner.【Method】Taking strong picking and no control as control, three kinds of low water-soluble pesticides of 24% chlorfenapyr, 15% indoxacarb, and 22% thiamethoxam+lambdacyhalothrin were selected and three application concentrations were designed to test their control effects on tea leafhoppers. And the young shoots of damaged tea leaves were picked to analyze the change of their main biochemical contents.【Result】There were differences in the main biochemical components of normal tea and the tea damaged by tea leafhoppers. The contents of tea
polyphenols, caffeine, and soluble sugar showed an upward trend and then a downward trend. The contents of amino acids and moisture showed a downward trend, of which the content of amino acids decreased by 22.7%, reaching significant difference. With the increase in the level of damage, the contents of tea polyphenols, amino acids, caffeine, soluble sugar, and moisture all showed a downward trend. After treatment for 1d, the effects of different treatments （from high to low） showed as: 24% chlorfenapyr>strong picking>22% thiamethoxam+lambda-cyhalothrin>15% indoxacarb, where the difference in the efficacy of 24% chlorfenapyr reached a significant level, and the effect was greater than 85%. The prevention and treatment effects of 15% indoxacarb and 22% thiamethoxam+lambda-cyhalothrin showed a trend of decreasing first and then increasing after treatment for 1 d. The lowest peaks reached at the 7th day （48.73%） and the 3rd day （26.19%） after drug application, and the highest peaks reached at the 21st day （90.74%, 83.80%） after drug application. The occurance number of tea leafhoppers showed a significantly negative correlation with picking frequency.【Conclusion】When the damage level of tea is Grade 1, it is better to adopt strong picking measures for prevention and control. The water loss of new shoots is light, and the phenol-ammonia ratio is relatively low. It is suitable to pick and produce green tea; When the damage level is Grade 2-3, it is suggested to take strong picking and 24% chlorfenapyr, and leaf quality of young shoots is crisp with high phenol-ammonia ratio, which is suitable for the production of black tea. |
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