This summer we are surveying commercial grower fields as part of an ongoing research project studying the impact of RBDV on ‘Marion’. To date, we have found this virus present in two commercial fields.

What is RBDV?

RBDV is a pollen- and seed-borne virus that is commonly found in red and black raspberry. In red raspberry, it reduces yield and induces drupelet abortion leading to crumbly fruit. RBDV is presently a major problem in the ‘Meeker’ industry in northern Washington. In 1998, we found that 27 of 54 ‘Marion’ blackberry plants sampled at the North Willamette Research and Extension Center were positive for RBDV. This planting was established in 1993 from tissue-cultured plants. This provided us with an opportunity to research the impact of this virus on ‘Marion’ as we can study infected and non-infected plants side-by-side.

For more information see the RBDV Web Site by Dr. Robert Martin, USDA Plant Virologist.

Impact of RBDV on ‘Marion’

In 1999, we hand harvested 17 RBDV-infected and 17 non-infected plants and obtained yield, berry weight and drupelet number/berry data. Yield was low in 1999, even on uninfected plants, due to winter damage. However, infection with RBDV reduced total yield by 50%, average berry size by 40% and drupelet number per berry by 39%. RBDV had no effect on berry number. However, due to the cold damage experienced in this planting in 1999, we decided to repeat this study in 2000 to make sure that the winter injury we saw last year did not affect the results.

Industry survey

We are presently collecting samples from commercial ‘Marion’ fields throughout the Willamette Valley to determine whether RBDV is present. This survey is necessary to determine the potential impact of RBDV on commercial ‘Marion’ production. To date (mid-June) we have found this virus in two grower fields. We need grower assistance to identify suspect fields. If you have noticed leaf symptoms that look like a yellowing on either fruiting cane (see Photo 1) or on primocane leaves later in the season (see Photo 3) contact us. Please note that symptoms of RBDV look different than those of another virus found in ‘Marion’ called Calico Virus (see Photo 2).

If you feel you have some “suspect” ‘Marion’ plants and would like to be included in our survery, please contact Jason Lett at 503-678-1264 x 47 or by e-mail at jason.lett@oregonstate.edu

Photo 1: Leaf symptoms of RBDV on fruiting laterals of ‘Marion’ (B. Strik)	Â
Photo 2: Leaf symptoms of Calico Virus on ‘Marion’ (B.Strik) Â Â Photo 3: Leaf symptoms of RBDV on primocane leaves of ‘Marion’ in summer (B. Strik)	Â

We’d like to thank the Oregon Raspberry & Blackberry Commission for their support of this research. For an update of our findings, attend the ORBC progress report day on December 14, 2000.