Issue link: https://read.dmtmag.com/i/705612
www.goodfruit.com Good Fruit Grower AUGUST 2016 33 confirmed in vineyards tobacco ringspot will involve clean plants and nematode suppression strategies. The symptomatic Grenache vines showed severe stunting and decline symptoms and poor fruit set, he said. The pathogen resides in the soil and can be a problem when grapes follow tree fruit crops like apples and pears. In this case, the virus did not have any impact on pears that were planted before the vineyard, but caused devas- tation in the wine grapes. Sampling of soil near the symptom- atic Grenache vines showed dagger nematode (Xiphinema rivesi) was the predominant nematode species. Further experiments using virus-free Cabernet Franc vines and cucumber seedlings planted near the symptom- atic Grenache vines as bait showed that the dagger nematode can transmit tobacco ringspot virus. "This is a classic example of a virus 'jumping' from one crop to another and serves as a learning experience for growers to keep in mind the crop history before planting wine grapes because some viruses may be a more serious problem to grapevines than to other crops," Rayapati said. —M. Hansen Grape viruses in WashinGton 1,500 samples collected from 2014 to 2015 Virus Percent testing PositiVe Grapevine leafroll associated virus 3 70 Grapevine red blotch associated virus 6 Grapevine leafroll and red blotch combined 8 Other viruses 16 Samples include red and white wine grape varieties collected from throughout eastern Washington. Samples for red varieties were taken based on visual virus symptoms, but samples were randomly collected for white varieties. Source: WaShington State univerSity