Submitted to: Caribbean Food Crops Society Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2005
Publication Date: 6/1/2005
Citation: Cook, J., Charudattan, R., Rosskopf, E.N., Zimmerman, T., MacDonald, G., Stall, W. 2005. Integrated control of dodder (Cuscuta pentagona) using glyphosate, ammonium sulfate, and the biological control agent Alternaria destruens. Proceedings of the Caribbean Food Crops Society Meeting. 6-8. Interpretive Summary:
Technical Abstract: Studies were conducted to develop an integrated control strategy for dodder (Cuscuta pentagona) using glyphosate, ammonium sulfate, and Alternaria destruens. In greenhouse studies, dodder parasitizing citrus was sprayed with glyphosate using 0%, 0.25%, 0.50%, 1%, 2%, and 4% concentrations of Roundup Pro® or ammonium sulfate at 0%, 1%, 2%, 3%, 4%, 5%, and 10% w/v. Five weeks after treatment (WAT) dodder plants treated with glyphosate were dead and the control plants were 95% dead. Highest levels of damage on citrus from glyphosate at 1%, 2%, and 4% ranged from 28% to 50%; the lowest levels, 10% to 20%, were from 0.25% and 0.5%. Five WAT, dodder in ammonium sulfate and control treatments necrosed; damage to citrus was <10%. In a field study, sunn hemp (Crotalaria juncea) naturally parasitized by dodder was hand-sprayed with 1.7 x 105 spores per ml of A. destruens at 100 ml per m2. The fungus was applied with and without a corn-oil-based carrier, PCC588. The fungal treatments produced 97% necrosis at 5 WAT; by 6 WAT, the control was 95% dead. Studies are underway to develop an integrated strategy using lowest effective levels of glyphosate, ammonium sulfate, and A. destruens. The reason for the damage and death of dodder in control treatments is also under investigation.