Abstract
A sampling program for red and black flat mite, Brevipalpus phoenicis (Geijskes), damage and population density was developed and tested at an Indonesian tea, Camellial sinensis, plantation. A photographic standard was developed With five damage classes increasing in damage intensity, indicated by leaf area discolored by B. plwerlicis feeding. Leaf damage' was evaluated by comparison With the photographic standard. The intraclass correlation method of Fisher was then used to test the repeatability of damage assessment by different field workers. In a population density experiment, transects were established in four tea fields. Leaf samples were taken monthly along each transect. The sample sizes required for density estimation with a relative error value of 0.20 are ≈100 and 300 leaves per plot for susceptible and resistant genotypes, respectively. Samples were also taken from a fifth field with plants grown from seedlings, and the required sample sizes for these plants the with hetero-generous genotypes fell between those values needed for pest resistant and susceptible clones. Because of tilt' stable coefficients of variation for the widely different mean mite densities measured during the season, a sample size of no more than 200 leaves per plot is recommended.
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