Targeted Virus Screen, Pear

Targeted Virus Screening starts with RNA from the plant tissue that is being tested, which contains both the plant’s native RNA and RNA from any other organism that was in the plant (including pathogens like viruses, viroids, or phytoplasma). This RNA is reverse-transcribed (“RT”-PCR) to generate DNA, which can then be used in a reaction called Polymerase Chain Reaction (PCR). PCR amplifies specific, targeted segments of the DNA so that there is enough to be able to detect it – in this case, we target sequences that are specific to the pathogens of interest, so that we detect a signal only if the pest of interest is present in the sample. Different pathogens can be detected separately by either using fluorescent tags  of different color (in qPCR) or by qualitatively measuring the amplification.

Comprehensive Virus Screening tests for all 2,500+ known plant pathogenic viruses, plus other common pathogens, and is the most sensitive detection method available. It is most useful for testing mother plants, new varieties, and pooled blocks of crops, or when you believe there is a complex or unknown infection in the crop.

Targeted Virus Screen is a more economical option to test for the diseases most commonly found in the crop of interest. This is most useful in cases where you see symptoms in the field and have narrowed down the cause to one or a small number of viruses.

We will contact you with sample preparation and shipping information after the test is ordered, but here are some pointers to get you started:

When to test: The best time to detect viruses is when they are actively replicating in the plant – and this can vary based on the virus you are targeting! A good rule of thumb is that June-August is the best time to test for most diseases, including testing for the viruses and phytoplasma that cause Little Cherry Disease.

Harvesting and Submitting Samples: Plan to use clean pruners for each separate tree/plant, and keep material from each plant separate in its own bag, even if samples are being pooled for testing. Provide 6” of stem/branch and 3-5 mature leaves for each plant. Keep all material cold, and ship as soon as possible via overnight courier.

What’s the turn-around-time?

We do all sample prep, testing, and analysis in house, so we can usually provide results in 2 weeks.

What if you don’t test for the virus that I’m interested in testing for?

We offer Comprehensive Virus Screening, which includes all plant pathogenic viruses. You can also Contact Us and let us know – we want to know what’s most important to you.