Report for period ending 9/2015 At the beginning of this reporting period we setup a greenhouse pot study to compare the spatial distribution of insecticide within citrus leaves. Previous preliminary work we conducted suggested that there is likely differences in the distribution of imidacloprid within leaf tissue that may affect the lognevity and amount of control provided by soil drench applications. Here, we examine this further and also examine movement of thiamethoxam and chothianidin as well. The insecticide concentration along the leaf margin was compared to the concentration in the leaf center. Citrus (v. Hamlin / r.s. Swingle) was planted to 3-gal pots containing a custom soil blend (50% sand, 50% potting media). The study was arranged in a randomized complete block design (RCBD) with 4 treatments and 4 replicates. Each plot consisted of 4 citrus trees 3-5 ft in height. A single insecticide application was made to the soil using 8 fl oz of insecticide solution per tree. Leaves were sampled prior to the insecticide application to ensure no insecticide was present, and again every 7 days, until the concentration fell to undetectable levels. At each sampling event, four leaves were removed from the upper canopy of each of the 4 trees within each plot. Leaves will be dissected into two regions: 1. leaf margin region (area 0.5 cm from leaf edge), and 2. leaf center region (area within 0.5 cm on each side of the mid-vein). Concentrations were analyzed using Liquid Chromotography-Mass Spectrometry. Due to number of samples to be analyzed, this experiment will be completed during the next reporting period.