Resistance to chemical seed and post-harvest treatments in isolates of Fusarium spp. causing potato seed-piece decay and tuber dry rot in Atlantic Canada
R.D.Peters, K.A. Seifert and H.W. (Bud) Platt.
Journal of Plant Pathology Volume 90 (2, Supplement) August 2008, Book of Abstract, 9th International Congress of Plant Pathology, August 24-29, 2008 Torino,Italy,. 507 pages.
2008
บทคัดย่อ
Resistance to chemical seed and post-harvest treatments in isolates of Fusarium spp. causing potato seed-piece decay and tuber dry rot in Atlantic Canada
VariousFusariumspp. can cause potato seed-piece decay priorto planting and tuber dry rot in storage, resulting in tuber yield and quality losses. In Atlantic Canada,F. sambucinum,F. coeruleumandF. avenaceumare the species most commonly isolated from diseased tuber tissue. Testing of isolates ofFusariumspp. collected in Atlantic Canada from 2000-2007 for resistance to thiophanate-methyl and thiabendazole using amended agar assays has revealed the association of resistance with a particular species. All isolates ofF. sambucinumrecovered during this time period were resistant to both thiophanate-methyl and thiabendazole, whereas all isolates ofF. coeruleumandF. avenaceumwere sensitive to both compounds. In field trials where potato seed pieces were inoculated with eitherF. sambucinumorF. coeruleumand then treated with either thiophanate-methyl, fludioxonil or water (control), significant yield increases (compared to the inoculated control plots) were achieved with both chemical seed treatments when seed pieces were inoculated withF. coeruleum.However, only plants in plots grown from fludioxonil-treated seed yielded significantly more than plants in inoculated control plots whenF. sambucinumwas used for inoculation. More recently (spring 2007),isolates ofF. sambucinumandF. coeruleumresistant to fludioxonil in amended agar assays have been recovered in Atlantic Canada. Since the isolates ofF. sambucinumwere also resistant to thiophanate-methyl and thiabendazole, multi-class (benzimidazole and pyrrole) resistance was also documented. Resistance ofFusariumspp. to chemical products is increasing the challenge of managing potato seed-piece decay and tuber dry rot in Atlantic Canada.