INTRAPLANT DISTRIBUTION AND SAMPLING OF THE CITRUS LEAFMINER (LEPIDOPTERA, GRACILLARIIDAE) ON LIME

The distribution and spatial dispersion patterns of citrus, Phyllocnis tis citrella Stainton, leafminer eggs and larvae were assessed in an e xperimental lime orchard in Dade County, Florida. Significantly higher egg and larval densities were found on apical leaves on young branche s compared with older, middle, and bottom leaves on young branches. Th e spatial dispersion pattern determined for larvae generally were aggr egated on 48-70% of the sampling dates. No significant differences in egg densities were observed among the top, middle, or lower tree canop y. However, egg and larval stages were considered statistically aggreg ated (b > 1) within the canopy. Sample size requirements for fixed lev els of precision were determined for eggs and larvae using estimated v ariance-mean relationships obtained from the Taylor power law regressi ons. The performance of the sampling plan was evaluated using resampli ng software. When egg densities fluctuated between 0.34 and 0.58 eggs per leaf, the performance of the sampling plan required too few sample s. Performance of existing sampling plans for larvae was low when larv al densities fluctuated between 0.12 and 0.16 larvae per leaf, but imp roved for higher densities greater than or equal to 1.97 larvae per le af. Mean samples sizes for a precision level of 0.25 were 10 leaves pe r tree.