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Investigators | Department | Objectives | Approach Keywords | Progress Reports | Impact Statements | Publications | |
Project * COL00225 | |
| Title | Biology and Management of Iris yellow spot virus (IYSV) and Thrips in Onions |
| Investigator(s) | Schwartz, HF; Cranshaw, WS; Bartolo, ME; Hammon, RW; |
| Department | Bioagricultural Sciences and Pest Mgmt. |
| Objectives | 1. Screen onion germplasm for improved levels of tolerance to Iris yellow spot virus (IYSV) and thrips 2. Study the biology and epidemiology of IYSV and thrips, and impacts of chemical, cultural and biological tactics that can reduce their impacts upon onions. 3. Transfer information on progress dealing with IYSV and thrips biology and IPM strategies to the onion industry and other interested parties |
| Approach | Objective 1 - Randomized, split-block design of 15 to 25 entries with 3 replicates; with 1 bed treated with an insecticide(s) to control thrips and the other bed left untreated. Plant population will be thinned to 18 emerged plants/linear meter per line. Count the average number of adult and larval thrips per plant on 10 plants for each entry and treatment at 4 and 2 weeks pre-bulbing, bulbing, 2 and 4 weeks post-bulbing. Estimate the IYSV ratings for each entry and treatment at bulbing, 3 and 6 weeks post-bulbing. Record percent incidence as proportion of 25 plants exhibiting symptoms of infection, and severity as an average rating of infected plants. Objective 2, methodologies will include the use of molecular tools such as DAS-ELISA and PCR/rt-PCR protocols. Using GPS/GIS technology, survey transects (10 to 25 km in length) will be established in major onion production areas with a history of IYSV, with 5 to 10 fields per transect. Plant samples (10 to 25 representative individuals of the target onion or weed species from in and around the sample field) will be collected (as aliquots of leaf, seed, stem tissues), stored on ice, and transported/mailed to the nearest laboratory for assay with ELISA and rt-PCR. Thrips will be counted from a bulked composite of 10 randomly selected onion plants at each plot grid on a 2 - 4 week interval. Representative thrips will be washed from plants using 70 percent ethanol, stored, and later classified to the species level. Objective 3, Participate in annual meetings of W1008 to update participants on current research and progress. Peer-reviewed research and extension publications, in addition to articles in trade magazines such as Onion World are also encouraged as a way to communicate with peers and growers. Information will be shared with collaborators in a common database that will be accessible via www.alliumnet.com. Milestones include: (2008) Implement an Onion IYSV/Thrips Evaluation Nursery to systematically evaluate onion germplasm; initiate development of transgenic plants with improved levels of resistance to IYSV; improve virus diagnostics with refinement of ELISA and PCR; expand knowledge on hosts of IYSV; technology transfer posted at www.alliumnet.com web site. (2009): Develop inoculation protocol; expand knowledge on biological and molecular properties of virus strains; identify stress factors involved in expression of IYSV in onion; describe virus movement within the plant; describe field relationship between virus and thrips on onion. (2010): Expand knowledge base on thrips species roles as a pest and/or vector; develop regional IYSV Risk Index Model and regional IYSV and Thrips IPM Strategies. (2011 and 2012): Evaluate transgenic plants for reaction to IYSV; validate regional IYSV Risk Index Model and regional IYSV and Thrips IPM Strategies. |
| Keywords | Germplasm Evaluation, Pest and Disease Management, Plant Virus Tolerance, Insect Pest Tolerance, Integrated Pest Management, Vegetable Production, Onion, Onion Thrips, Iris Yellow Spot Virus, Pest and Disease Biology, Pest and Disease Epidemiology, Cultural Practice Modification |
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