Abstract
Abstract A randomized complete block experiment with 6 single-tree replicates and 4 treatments was conducted in a field of 15-ft trees in a 20 × 24-ft planting at the Citrus Experiment Station in Riverside, California. Pretreatment densities of California red scale (CRS) were evaluated in late Apr ’84 by examining in each plot 75 9-in twigs from the previous growth flush that were randomly selected from around the trees. Each sample unit was scored in situ as being infested or not infested with live CRS. Posttreatment counts were made in late Sep ’84 and again in mid May ’85 by examining 75 twigs and 100 fruit per plot in a similar manner. Fruit counts were included in the posttreatment evaluation because they are an index of how well a treatment prevented the current crop from becoming infested and consequently downgraded, thus determining the immediate benefit of the treatment. Twig counts were evaluated to determine how well a treatment suppressed scale population growth. The single tree plots were assigned to blocks on the basis of pretreatment twig counts and on position in the field (one row of trees, for some unknown reason, tended to have high posttreatment counts for all treatments). Thus, plots within each block had similar pretreatment counts and were located in the same part of the field. Treatments were randomly assigned to each of the 6 blocks. The Rol6-1295 0.063 lb/100 gal treatment was not applied in 1 of the blocks; all other treatments were represented in each block. Pesticides were applied with hand guns from the ground and from a tower at ca 505 psi and ca 17.45 gal/tree (ca 1584 gal/A) on 7 Jun ’84. Age class distribution of CRS at this time was estimated as ca 50% adult and 50% immature stages.
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