Zebra chip, a new and economically important disease of potato, Solanum tuberosum L., in the United States, Mexico, Guatemala, Honduras, Nicaragua, and New Zealand has caused millions of dollars in loss to the potato industry. The disease is associated with the bacterium “Candidatus Liberibacter solanacearum” transmitted to potato by the potato psyllid, Bactericera cockerelli (Sulc). Since its initial U.S. appearance in southern Texas in 2000, zebra chip has caused serious damage to potato production in the state, often leading to abandonment of entire fields. A study at Weslaco assessed the impact of potato planting time on incidence of zebra chip in the Lower Rio Grande Valley of Texas. Non-treated experimental potato plots were planted in mid-December to midFebruary for 4 years, and incidence of zebra chip was estimated at harvest each potato-growing season. Results showed that, in the Lower Rio Grande Valley, potatoes planted early were more affected by zebra chip than were those planted later, with infection rate ranging from 23.2 to 72.7, 20 to 44.6, and 5.4 to 31.2% in potato plots planted in December, January, and February, respectively. The reasons behind this differential in disease incidence are unknown; however, rate of infection by “Candidatus Liberibacter solanacearum” of psyllids colonizing potatoes in the region is suspected. Information from this research will help growers in southern Texas whose potatoes are affected by zebra chip to minimize losses caused by this damaging disease by timely planting of potatoes and appropriately protecting fields from colonization by the potato psyllid.