Submitted to: Proceedings of Northeastern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/6/2003
Publication Date: 1/5/2004
Citation: Bruckart, W.L., Cavin, C.A. 2004. Fungicide control of the biological control candidate colletotrichum gloesporioides on spinach. Proceedings of Northeastern Weed Science Society. 58:160.
Technical Abstract: A strain of Colletotrichum gloeosporioides (CG) from Hungary is under evaluation for biological control of Russian thistle (Salsola tragus) in the United States. In preliminary tests, minor symptoms of infection were noted on older or flower spinach that would not likely affect vegetable production. Other mitigating factors might eliminate risk to spinach from CG. This study was run to test whether fungicides registered on spinach would also control either CG or C. dematium (CD), a U.S. pathogen of spinach. The first test with Kocide 2000 (53.8% Copper hydroxide was run in a 2x3 factorial treatment design including all combinations of the fungicide and either CG or CD. Kocide was applied at 2.52 kg/ha to 4 wk old spinach plants, which were then treated either with CD (0.5x106 conidia/ml), CG (1x106 conidia/ml), or they were left uninoculated. Following dew for 16 hr at 25 C overnight, and incubation for 4 wk in a greenhouse at 20 C and a 12 hr photoperiod, plants were rated for disease and biomass data were collected. There were no differences between treatments with CG, with or without Kocide, and the controls. Spinach plants inoculated with CD, with or without Kocide, had significantly less biomass than controls. CG did not damage spinach and Kocide did not control CD in this study. Another fungicide, Quadris (Azoxystrobin) is being tested.