チャ園におけるチャノミドリヒメヨコバイの発生密度と新芽における被害との関係

抄録

We investigated the relationship between the density of the tea green leafhopper, Empoasca onukii Matsuda, in tea fields and damage to new shoots of the tea crop. The density of E. onukii, determined by beating the tea canopy, was investigated twice before plucking, and the damage rates of plucked new shoots were determined. The correlation between the density and damage rate was higher when the cumulative density from the two survey times were used than when data from only one survey were used. The relationship between the cumulative density from two surveys (x) and the damage rate (y) produced the following regression equation: y = 1 – exp(–0.0227x), R² = 0.76, n = 99. The relationship between the damage rate (x: angle conversion value) and the damage indexes: Σ(each grade × number of damaged shoots, applying grade values from 0 to 6)/6 × total number of shoots checked (y: angle conversion value), showed a high correlation (R² = 0.99, n = 30). It is suggested that these results can contribute to the development of a technique for controlling the density of E. onukii to produce special tea containing diol induced by E. onukii damage.