|Picton, Deric - OREGON STATE UNIVERSITY|
Submitted to: Small Fruit Reviews
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 25, 2003
Publication Date: January 1, 2003
Citation: Small Fruit Review, Volume 2, Number 1 2003, ISSN: 1522-8851, Page 43-49 Interpretive Summary: White pine blister rust can severely infect black currant leaves in North America. This rust can kill white pine trees, which are an alternate host for the disease. Environmentally sound control measures are being sought as alternatives to eradication or prohibition of black currant production. This study examined the effect of mineral oil spray on infection in seven black currants. Mineral oil was sprayed on currants at 0, 4 wk, and 2 wk intervals from August through Mid- October in 1999 and 2000. Leaves were rated for the percentages of rust infection in Mid-October 2000. Oil applications significantly reduced rust on susceptible cultivars as compared to that the unsprayed control. In Corvallis, application of oil every two weeks resulted in the greatest amount of rust control on the most susceptible black currants. This study suggests that oil spray could be considered for controlling rust on cultivated black currants where infection is of concern.
Technical Abstract: White pine blister rust (Cronartium ribicola Fisch.), an economically important disease of five-needled white pines (Pinus L. section strobus), also infects leaves of black currants (Ribes nigrum L.), as an alternate host. Recommended rust control-procedures include eradication, prohibition, or restriction of planting or growing black currants in specific states. Chemical or cultural control techniques for cultivated Ribes have been neglected in rust Management plans. The objective of this study was to examine the effect of mineral oil spray on rust infection in susceptible cultivated black currants. Mineral oil at 8 ml/L was sprayed to runoff at 0, 2-week, and 4-week intervals from August through October 2000 on rust- infected black current cultivars growing in Corvallis, Oregon. Leaves were visually rated for percent infection in mid-October. Mineral oil applications significantly reduced rust infection as compared to that of the unsprayed control. The infection of 3 highly susceptible cultivars treated every two weeks was significantly less than that of control plants. One of the three highly susceptible cultivars showed significant reduction in infection when compared to the two-week treatment. The four least susceptible cultivars did not show significant reduction in infection when compared to the control. Infection was significantly reduced in the most susceptible black currants. Mineral oil application could reduce rust on cultivated susceptible black currants in areas where this infection is of concern.