Control of Dutch elm disease by the sterol biosynthesis inhibitors fenpropimorph and fenpropidin
article
Sterol biosynthesis inhibitors that inhibit the yeast-hyphae conversion in Ophiostoma ulmi suppressed Dutch elm disease development in two elm clones. After curative treatment with fenpropimorph-sulphate of 27 'Vegeta' elms which had previously been inoculated with O. ulmi, 25 trees did not show disease symptoms by the end of the second season. All 41 control trees, inoculated with O. ulmi only, were clearly diseased. In an experiment with 'Commelin' elms three fenpropimorph salts and thiabendazole were compared. Injection of the trees three weeks after inoculation with O. ulmi gave by the end of the second season no symptoms of Dutch elm disease in any of the trees injected with fenpropimorph-phosphate or thiabendazole, and in most trees injected with fenpropimorph-acetate or-sulphate. Similar treatments with the free base of fenpropimorph and fenpropidin-sulphate were less effective due to insufficient uptake of the fenpropimorph emulsion and phytotoxicity of fenpropidin-sulphate, respectively. Injection of fenpropimorph-sulphate or thiabendazole six weeks after inoculation with O. ulmi did not result in significant differences from the control group inoculated with O. ulmi only. Fenpropimorph-phosphate and-sulphate completely suppressed Dutch elm disease upon injection of only 7.5 or 10 g per tree (average tree diameter 28 cm). Residue analyses showed only a slow decrease in concentration of the fungicide over two growing seasons and an apparent transport into the new annual ring, other prerequisites for a possible future use for control of Dutch elm disease. © 1988 Koninklijke Nederlandse Planteziektenkundige Vereniging.
Topics
TNO Identifier
230670
ISSN
00282944
Source
Netherlands Journal of Plant Pathology, 94(3), pp. 161-173.
Pages
161-173
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