Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 10/24/2004
Publication Date: 12/1/2004
Citation: Cook, J., Charudattan, R., Rosskopf, E.N., Zimmerman, T., Macdonald, G., Stall, W. 2004. Integrated control of dodder (cuscuta pentagona) using glyphosate, ammonium sulfate, and the biological control agent alternaria destruens. Proceedings of the 27th Annual Florida Weed Science Society, p. 3. Interpretive Summary:
Technical Abstract: Greenhouse and field studies were conducted to develop an integrated weed management system for dodder (Cuscuta pentagona) using glyphosate, ammonium sulfate, and the biological control agent Alternaria destruens. In greenhouse studies, dodder was vegetatively propagated on citrus plants and the treatments were applied with a hand-held sprayer. There were 4 replications and the studies were repeated once. Glyphosate was applied at 0%, 0.25%, 0.50%, 1.0%, 2.0%, and 4.0% of the labeled rate, while ammonium sulfate was applied at 0%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, and 10.0% w/v in water. By 2 weeks after treatment (WAT), dodder treated with 2.0% and 4.0% glyphosate exhibited 100% injury. By 4 WAT, all dodder plants, excluding those at 0%, were dead. At 1 WAT, dodder with glyphosate applied at 0% started to exhibit symptoms of injury and by 5 WAT was 95% dead. The greatest amount of injury was observed with glyphosate at 1.0%, 2.0%, and 4.0%. In the first trial of the ammonium sulfate experiment, no differences were observed in any of the treatments, except between the 0% and 1%. In the second trial, the damage level from 0% and 10.0% ammonium sulfate was not different from each other but was different from the damage at 1.0%. The greatest amount of injury observed was 98% by 4 WAT. In the field study, Sunn hemp (Crotalaria juncea) naturally parasitized by dodder was inoculated with 1.7 x 105 fungal spores per ml and applied with a hand-held sprayer at 100 ml per m2. A. destruens was applied with and without the oil PCC 588. Preliminary results indicate that by 5 WAT, 95% of dodder treated with A. destruens with and without oil was dead. By 6 WAT, both untreated dodder and dodder treated with oil were 95% dead. Management and control of dodder can possibly be achieved through use of this integrated weed program. The reason for the gradual increase in damage of the untreated control plants is under investigation.