Lettuce Mosaic Virus Testing
The ELISA assay method that is used to detect lettuce mosaic virus (LMV) developed by our laboratory is combined with a highly refined statistical analysis of the data. It is a very sensitive and specific test which can be routinely used to detect 1 infected seed in 30,000, as required in California counties where lettuce is grown commercially. We test both seed and leaf tissue for LMV.
SAMPLING: Please submit a sample of 3-4 oz (75-100gm), and include specific seedlot identification for the certificate. Our delivery address is:
Regular (Samples are processed in the order of arrival)
Rush (Quaranteed 2nd-Day Delivery of Results)
Speed-LMV : Results available the same day!
Statistical Evaluation of Lettuce Seed Lots
Lettuce seed lots which are received for evaluation by the standard 30,000 seed assay are subdivided into 60 samples (sublots) of approximately 500 seeds each. Research conducted at the University of California, Davis, and the University of Florida has previously shown that assaying sublots of this size maximizes both the sensitivity and efficiency of the assay. Each sublot is then analyzed by an Enzyme-Linked Immunosorbent Assay (ELISA) for the presence of LMV. Based on the results obtained from the assay of the 60 sublots, two rates are deduced:
Observed Rate of Infection: The number of LMV-infected seeds detected from the 30,000 seeds actually assayed.
Statistical Rate of Infection: An extrapolation of the Observed Rate of Infection which attempts to estimate the rate of infection in the entire seedlot.
Mosaic Symptoms on LettuceYoung plants first show a slight leaf rolling, followed by light green to yellow mottling. Foliage has a yellowish color and plants are small or dwarfed. Symptoms vary according to type or variety of lettuce. The virus is seed-borne and overwinters in wild hosts and weeds. Infected seed is the most common source of infection. Once infected plants are present in the field, aphids will continue to spread the virus. There is no cure for mosaic once a plant is infected. The control is to use virus-free seed.
Soil Content AssaysIf determination of soil content of the seedlot is needed, please submit a 100 gm sample, and include specific seedlot identification for the report. Our delivery address is: