Determination of the sampling unit and spatial distribution of Leptopharsa gibbicarina (Hemiptera: Tingidae) in oil palm plantations.

Our research aimed to establish a practical methodology for monitoring populations of Leptopharsa gibbicarina Froeschner (Hemiptera: Tingidae) in oil palm plantations. This innovative approach will enable oil palm growers to detect early increases in these populations and implement necessary control measures on time. We identified the most suitable palm leaf sections and sampling intensity by selecting 30 palms on a commercial plantation. We divided each leaf into three sections (apex, middle, and base) and recorded the number of L. gibbicarina adults in each section every 20 d for a period of 6 mo. The data were analyzed using GLM, the Tukey test, and Poisson regression. Our findings revealed significant statistical differences (P < 0.05) in the number of L. gibbicarina across different leaf sections. Specifically, the apex and the middle part of leaves 25, 31, and 24, recorded the highest number of L. gibbicarina adults. Additionally, we determined the appropriate sampling intensity by recording the number of L. gibbicarina at the apex of leaf 25 across all palms in a 15.3-hectare plot every 20 d for 1 yr. The data were further analyzed through lattice analysis, and the Moran index was calculated. The results indicated that sampling intensity depended on the plot's level of L. gibbicarina infestation and that sampling grids can vary from one palm every five palms every five lines of palms (45 m × 45 m) to one palm every thirteen palms every thirteen lines (117 m × 117 m). These findings are invaluable for optimizing the sampling of L. gibbicarina in oil palm plantations, making a significant contribution to the fields of entomology and agriculture.