|SHRESTHA, ANIL - Fresno State University|
Submitted to: Entomological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/2/2012
Publication Date: 3/25/2012
Citation: Krugner, R., Ledbetter, C.A., Chen, J., Shrestha, A. 2012. Phenology of Xylella fastidiosa and its Vector, Draeculacephala minerva, in vegetation surrounding California Almond Nurseries. Entomological Society of America Proceedings, Pacific Branch Meting, March 25-28, 2012, Portland, Oregon. p. 21.
Technical Abstract: Management of almond leaf scorch disease requires knowledge of all possible infection pathways. The disease is caused by the xylem-limited bacterium Xylella fastidiosa, which is transmitted by several species of leafhoppers. The objectives of this research were to elucidate the fate of bacteria in planta after inoculations in almond nursery plants and to determine patterns of insect vector population dynamics and temporal distribution of X. fastidiosa-infected plants relative to host plant assemblages in habitats surrounding commercial nurseries. In an experimental nursery, disease incidence was markedly affected by rootstock type. Prior to bud grafting, ‘Nemaguard’ rootstock seedlings were immune to bacterial infection. After bud grafting with a susceptible scion, scions were susceptible to infection regardless of rootstock genotype. Surveys in commercial nurseries revealed that only habitats with permanent grass cover sustained vector populations throughout the season. A total of 87 plant samples tested positive for X. fastidiosa (6.3%) using ELISA, with a higher number of X. fastidiosa-infected plants found in weedy alfalfa fields than in other habitat types. Among plant species infected by X. fastidiosa, 33% were winter annuals, 45% were biennials or perennials, and 22% were summer annuals. Collectively, these findings identified a potential pathway for X. fastidiosa infection of almonds.