Note to readers, attached is the complete final report for FNE99-262
Rodolfo worked with Steve McKay of Cornell Cooperative Extension on this project. Their objectives were to develop better propagation techniques for Ribes, test these on various Ribes cultivars, and experiment with the use of stylet oil for control of mildew and blossom blight.
Method: Steve and Rodolfo collected cuttings from 30 cultivars in September and January. Those collected in September were placed in water, to promote root growth. Those collected in January were wrapped in moist paper towel, placed in sealed plastic bags, and kept in a refrigerator, also to promote root growth.
Findings: Of the September cuttings, black currants initiated root growth in 6 to 10 days. Red currants callused, and some initiated root growth in 10 to 14 days. Only 25% of the gooseberries produced roots, and this took about a month.
Of the January cuttings, all of the black currants, 75% of the red currants, and 15% of the gooseberries, had callused or initiated roots by March.
2) Disease control
Method: A field experiment was set up to compare various treatment schedules for application of stylet oil (2% formulation, with Cu) for control of fungal diseases. The treatments are a) pre-bloom and post-bloom, b) pre-bloom, post-bloom, and every two weeks thereafter, c) pre-bloom, post-bloom, and “as necessary” thereafter, and d) control receiving no spray.
Findings: Initial results indicate that the pre- and post-bloom applications are critical. Whether further applications are necessary beyond that is yet to be determined.
Currant cuttings should be taken between September 15 and October 15. Cuttings can be placed in water for five days before planting to help initiate root growth, though this may not be necessary. Leaves can be removed from the cuttings. Gooseberries will be more successfully propagated by stooling (partially burying a low-growing stem in the earth), and removing the rooted stem from the mother plant in September.
Cuttings can be taken in the winter. Winter cuttings should be wrapped in a moist paper towel, placed in a sealed plastic bag, and kept refrigerated at about 38-40 °F, colder if kept into April, because fungus can become a problem. Cuttings that develop roots, if not planted, should be kept at 33 °F.
Currant cuttings establish well in the field, when planted in September. Gooseberries do too, but only if they are taken from stooled plants.
For disease control, pre-bloom and post-bloom applications (at least) of copper and stylet oil are recommended, to control mildew, Botrytis, and leaf spot. The oil can eliminate an existing infection of mildew.
The Titania variety of black currant is recommended, as immune to both mildew and white pine blister rust. Gooseberries and red currants are more resistant to rust than are most of the black currant cultivars.
Steve projects a strong demand for currants and gooseberries, particularly in gourmet and ethnic markets, and says that current production falls far short of satisfying that demand. He is promoting the cultivation of Ribes throughout New York, and is working with Cornell to develop value-added products.