Distribution pattern and estimation method for the population density of Polyphagotarsonemus latus (Banks) in tea [Camellia sinensis] field
1995
Kawai, Y. (National Research Inst. of Vegetables, Ornamental Plants and Tea, Ano, Mie (Japan))
Distribution patterns in a tea shoot and in a tea field and an estimation method for the population density of Polyphagotarsonemus latus (Banks) were examined at field and in netted house. Most mites infested on two upper developed leaves of new shoot. The rate of the mites infested on the upper leaves was higher in netted house than at field. The most number of mite were observed on lower surface of a leaf. The rate of the mites infested on lower surface was higher in field than at netted house. The distribution of adults, larvae or eggs were contagious both in field and at netted house. Adults and larvae were distributed as individual and eggs were distributed as colony a field, and these three stages were distributed as colony in netted house. From the distribution data obtained, a sampling method for estimating population density was proposed, i.e. two upper developed leaves should be sampled, and numbers of mite on lower surface of the leaf should be counted. The relationship between the precision of the estimation and the number of new shoots required to estimate the population density was discussed
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