チャにおけるチャノナガサビダニの葉位別寄生密度と増殖能力の品種間差異

抄録

The adult density of the tea rust mite, Acaphylla theavagrans Kadono, on tea leaves at different levels and the reproductive rate of the mite were investigated in the laboratory using different tea varieties and lines. The adult density of the mite was highest on the 4th to 5th leaves from the terminal leaf. Laboratory experiments revealed that females laid more eggs on the middle leaves. The difference in the adult density in relation to the leaf order was mainly caused by a difference in the oviposition rate of the mite since the number of eggs laid per 20 females for 3 days was the highest on the 5th leaf. Among the 8 Japanese cultivars, the number of eggs laid per 20 females for 3 days varied from 34.8 on the ‘Kuritawase’ to 97.8 on the ‘Ooiwase’ and were significantly different among the varieties. Large differences in the number of eggs were found among the 9 introduced tea lines, ranging from 3.5 on the ‘Miya taiwan-yamacha’ to 63.5 on the ‘Chinshindapan.’ Moreover, the intrinsic rate of natural increase varied from 0.1559 on the ‘Miya taiwan-yamacha’ to 0.1973 on the ‘Chinshindapan.’