2011 Annual Report 1a.Objectives (from AD-416) Increasing the understanding of the zebra chip potato disease vector biology, vector-pathogen interaction, and the epidemiology of the disease. 1b.Approach (from AD-416) Assess the role of the potato psyllid in zebra chip potato disease by:. 1)conducting insect transmission studies under laboratory conditions to determine liberibacter acquisition and inoculation access time required for the potato psyllid to effectively transmit the bacterium and induce zebra chip,. 2)determining the impact of zebra chip on different plant growth stages under controlled field cage conditions,. 3)determining density of potato psyllid required for this insect pest to effectively cause zebra chip,. 4)assessing environmental conditions that may influence ZC symptom expression, including temperature, relative humidity, and light intensity, and. 5)screening potato breeding material for zebra chip. Documents Reimbursable with Texas A&M (SCRI). Log 44012. 3.Progress Report The project goal is to develop effective management strategies for potato psyllid and zebra chip disease. The project addresses NP 304 2A, Protectioin of Agricultural and Horticultural Crops, Biology and Ecology of Pests and Natural Enemies, and 2B, Protection of Agricultural and Horticultural Crops Control. Zebra chip, an important disease of potato in US, Mexico, Central America, and New Zealand, is causing millions of dollars in losses to the potato industry. It has been determined that the disease is associated with a new species of the bacterium liberibacter that is transmitted by the potato psyllid. The main objective of the present research project is to increase the understanding of the zebra chip potato disease vector biology, vector-pathogen interaction, and the epidemiology of the disease. As a continuation of the project #5352-22000-018-19R, experiments were conducted to:. 1)determine insect transmission under laboratory conditions to further determine liberibacter acquisition and inoculation access time required for the potato psyllid to effectively transmit the bacterium and induce zebra chip,. 2)determine the impact of zebra chip on different plant growth stages under controlled field cage conditions,. 3)determine density of potato psyllid required for this insect pest to effectively cause zebra chip,. 4)assess environmental factors that influence zebra chip disease severity, and. 5)screen most important potato varieties in US and advanced potato breeding lines for zebra chip disease. It was found that single potato psyllid can transmit liberibacter to potato in a period as short as 2 hours and cause zebra chip. In addition, it was found that temperature has a significant impact on zebra chip disease development, with high temperature preventing development of zebra chip and liberibacter. Furthermore, several advanced breeding lines exhibiting some tolerance to zebra chip were identified. This information enables the development and adoption of better and sustainable management strategies for this disease. This project is an extension of research on the management of insects vectoring potato diseases and addresses objective 3 of the related in-house project. Monitoring of activities and progress on this project was accomplished by direct supervision of on-site employees, and use of site visits, e-mail and telephone to communicate with off-site collaborators.