1a.Objectives (from AD-416)
Develop integrated pest management of the potato psyllid and Liberibacter in a multicrop system.

1b.Approach (from AD-416)
Conduct 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 diseases. Determine the impact of Liberibacter on different plant growth stages under controlled field cage conditions. Determine density of potato psyllid required for this insect pest to effectively cause diseases in potato, tomato, and pepper.

3.Progress Report

“Zebra Chip” is an emerging and serious disease which severely reduces the quality of potato tubers used for producing potato chips and other processed potato products. The symptoms in diseased tubers often appear as stripes or streaks, thus the name zebra chip. The disease is caused by a bacterium, Candidatus Liberibacter solanacearum (= psyllaurous), which is transmitted to the potatoes by the potato psyllid. In order to better understand the role of the psyllid and alternate host plants, we have infested several weeds with psyllids. Results indicated all of the weeds were hosts of the bacterium. This has implications in the epidemiology of this disease. The occurrence of the psyllid was also studied in several locations in southern California on tomatoes, bell peppers, and potatoes. Results showed variation in the timing of arrival of the psyllid on different crops and the most psyllids were reported on tomatoes. Several species of beneficial insects that parasitized or fed upon potato psyllids were identified. These results provide useful information on the biology of the potato psyllid, role of different crops, and suggest biological control strategies for this important insect. This project contributes to Objective 2 of the parent project. The project was monitored through phone and email conversations.