Abstract: In order to define occurrence regularity of thrips in flue-cured tobacco at seedling stages, and explore techniques of releasing predatory mites against thrips in flue-cured tobacco at seedling stages, both the population dynamics of thrips and optimum release pattern of predatory mites in seedling stage of flue-cured tobacco were systematically studied. The results showed that after the emergence of flue-cured tobacco, the harm of thrips could be seen, and the population density increased gradually until reaching the peak before transplanting （about amount of 29.34 per 50 strains）, which decreased sharply after transplanting; The quick action of flaky release was significantly better than that of punctate release, but the lasting effect was significantly worse than that of punctate release; After the 40 days of punctate release, no matter in terms of population decline rate or control effect, the punctate release method was better than the flaky release method. When using predatory mites to control thrips in flue-cured tobacco at seedling stage, they should be released as soon as possible after emergence; When the number of thrips population in the seedling stage was large, it was recommended to use the surface release method to control the thrips; When the number of thrips population in the seedling stage was low, it was recommended to use the punctate release method to control the thrips.

Key words: flue-cured tobacco, thrips, occurrence regularity, predatory mite, control effect