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United States Department of Agriculture

Agricultural Research Service

Title: Spore viability bioassay, in vitro and greenhouse evaluation of six potential methyl bromide alternatives

item Iriarte, Fanny
item Rosskopf, Erin

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/11/2011
Publication Date: 6/1/2007
Citation: Iriarte, F.B., Rosskopf, E.N. 2007. Spore viability bioassay, in vitro and greenhouse evaluation of six potential methyl bromide alternatives. American Phytopathological Society Annual Meeting.

Interpretive Summary:

Technical Abstract: Six test compounds were evaluated in vitro for their effectiveness in control of Phytophthora capsici, P. nicotianae, Pythium aphanidermatum, P. myriotylum, Sclerotinia sclerotiorum, Athelia rolfsii, Fusarium oxysporum, Colletotrichum acutatum, Rhizoctonia solani and Verticillium albo-atrum. Four of the materials (AJMC-83, AJMC-364, AJMC-333 and AJMC-331) inhibited mycelial growth of all fungi at 100 or 200 ppm. Higher concentrations (1000 to >=2000 ppm) were needed in the case of 2-bromoethanol and 2-iodoethanol, previously patented materials. A tetrazolium-based bioassay showed similar results. Most of the compounds significantly reduced spore viability of F. oxysporum, V. albo-atrum. P. capsici, P. aphanidermatum and C. acutatum at 100 ppm or 500 ppm. Similar techniques to evaluate sclerotia-forming fungi and Rhizoctonia are under investigation. In greenhouse evaluations, phytotoxicity symptoms of stunting, chlorosis and defoliation (pepper only) were observed in pepper and tomato when plants were transplanted before 15-20 days after soil treatment. No phytotoxicity was observed when plants were transplanted 20 or more days after soil treatment. Greenhouse assays of the other pathogens are underway.

Last Modified: 08/20/2017
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