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earlier years. Primer design is of most importance in any PCR assay, conventional or real-time, especially when aiming to detect RNA viruses. To assure proper detection, primers and probes are designed to target conserved areas of virus genome. These are areas that often serve essential biological functions or are of ultimate necessity for the organism. Therefore. they are kept unchanged or minimally altered over generations of viruses. To overcome variability between strains, sometimes several different primers and probes have to be designed. Different qPCR chemistries can also offer different levels of stringency for detection. While probe-based assays are highly specific (stringent), research suggests that SYBR Green assays may allow more variability within the target sequence. A good example is our GLRaV-3 SYBR Green assay that is capable of detecting more variable members of GLRaV3, including group VI variants such as ���Napa strain.��� QUANTIFICATION OF GRAPEVINE POWDERY MILDEW For years, measuring the amount of virus in grapevine tissue was not possible, even though seasonal variation in virus titer was a known phenomenon. Now with qPCR, such approaches are at our finger tips. In the recent International Council for the Study of Grapevine Virus and Virus-Like Diseases of the Grapevine (ICVG) meeting at UC Davis in October 2012, several qPCR-based assays were presented for quantification of grapevine viruses. The primary take-home message from these studies for diagnostic purposes is that viruses can be detected now with qPCR throughout the year. Even more, these assays have much broader applications in studying virus ecology and transmission, and provide valuable tools for plant breeders for disease assessment. Pathogen quantification is of great importance in epidemiological studies where monitoring of disease pressure is needed. This past growing season, AL&L Crop Solutions offered qPCR assay for monitoring of powdery mildew spores in the vineyard air. The method is highly sensitive with a detection limit of less than 10 spores. High sensitivity is essential in order to detect first release of ascospores, the initial inoculum for powdery mildew each season. This technology can be a powerful tool in vineyard IPM programs intending to apply more targeted approaches for powdery mildew control. In 2013, our goal is to expand the project for monitoring the presence of spores of Eutypa and Botryosphaeria fungi, to provide growers with real-time information that can be used for making decisions about the timing of pruning. GOLD STANDARD The qPCR technology is demonstratively more sensitive than ELISA and classical PCR methods. It provides superior specificity, allowing for the identification of various sub-pathogen types. Because of these two qualities, it is adaptable and has the potential to be used in the monitoring of disease development and the implementation of future pest management strategies. The qPCR technology will rapidly become the ���gold standard��� for identification and research in plant pathology, if this has not already taken place. Anna-Liisa Fabritius is a plant pathologist and owner, and Lana Dubrovsky is a lab manager and owner, of AL&L Crop Solutions Inc., in Davis, Calif. Both can be contacted at (530) 387-3270 or info@ allcropsolutions.com. Comments? Please e-mail us at feedback@vwmmedia.com. www.enartisvinquiry.com EVQ_WINE STABILITY_WBM OK tr.indd 1 w w w. v w m media.com J a n - F e b 2 0 13 | V I N E YA R D & W I N E RY 06/12/12 E M E N T M A N A G 11:17 79