Sensitivity to Azoxystrobin Among Isolates of Uncinula necator : Baseline Distribution and Relationship to Myclobutanil Sensitivity

Two hundred fifty-six single-conidial chain isolates of Uncinula necator were assayed for their sensitivity to azoxystrobin and myclobutanil. These isolates were collected from two sites in New York in 1999: an "organic" vineyard where no synthetic fungicides have been used (baseline popul...

Ausführliche Beschreibung

Bibliographische Detailangaben
Veröffentlicht in:Plant disease. - 1997. - 86(2002), 4 vom: 01. Apr., Seite 394-404
1. Verfasser: Wong, Francis P (VerfasserIn)
Weitere Verfasser: Wilcox, Wayne F
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2002
Zugriff auf das übergeordnete Werk:Plant disease
Schlagworte:Journal Article
LEADER 01000naa a22002652 4500
001 NLM294430970
003 DE-627
005 20231225081448.0
007 cr uuu---uuuuu
008 231225s2002 xx |||||o 00| ||eng c
024 7 |a 10.1094/PDIS.2002.86.4.394  |2 doi 
028 5 2 |a pubmed24n0981.xml 
035 |a (DE-627)NLM294430970 
035 |a (NLM)30818714 
040 |a DE-627  |b ger  |c DE-627  |e rakwb 
041 |a eng 
100 1 |a Wong, Francis P  |e verfasserin  |4 aut 
245 1 0 |a Sensitivity to Azoxystrobin Among Isolates of Uncinula necator  |b Baseline Distribution and Relationship to Myclobutanil Sensitivity 
264 1 |c 2002 
336 |a Text  |b txt  |2 rdacontent 
337 |a ƒaComputermedien  |b c  |2 rdamedia 
338 |a ƒa Online-Ressource  |b cr  |2 rdacarrier 
500 |a Date Revised 20.11.2019 
500 |a published: Print 
500 |a Citation Status PubMed-not-MEDLINE 
520 |a Two hundred fifty-six single-conidial chain isolates of Uncinula necator were assayed for their sensitivity to azoxystrobin and myclobutanil. These isolates were collected from two sites in New York in 1999: an "organic" vineyard where no synthetic fungicides have been used (baseline population) and a commercial vineyard having a history of compromised powdery mildew control with myclobutanil (demethylation inhibitor [DMI]-resistant population). Mean coefficients of variance for a leaf disk assay used to test fungicide sensitivities were 31% for azoxystrobin and 41% for myclobutanil. Baseline ED50 values ranged from 0.0037 to 0.028 μg/ml (mean 0.0097μg/ml) for azoxystrobin and from 0.0049 to 0.69 μg/ml (mean 0.075 μg/ml) for myclobutanil. A shift in the mean ED50 value for azoxystrobin to 0.018 μg/ml was observed in the DMI-resistant population; with the strongest shift observed for isolates collected from vines treated exclusively with myclobutanil (0.024 μg/ml). For the 256 tested isolates, there was a moderate, but statistically significant, correlation between azoxystrobin and myclobutanil sensitivities (R2 = 0.36, P < 0.001). Tests with three other strobilurin fungicides (kresoxim-methyl, pyraclostrobin, and trifloxystrobin) indicate clear differences in the intrinsic activity of these compounds against U. necator, and the applicability of the methods developed with azoxystrobin for assays with pyraclostrobin and trifloxystrobin. Isolates from the high and low ends of the azoxystrobin sensitivity distribution (15× difference in mean ED50 values) were equally controlled in planta by protectant or postinfection treatment with azoxystrobin at 250 μg a.i./ml, but postinfection application at lower rates (2.5 and 25 μg a.i./ml) resulted in a 41 and 44% decrease, respectively, in the control of the low-sensitivity isolates versus high-sensitivity isolates. The results of this study document the baseline sensitivity distribution of U. necator to azoxystrobin, provide evidence of partial cross-sensitivity between azoxystrobin and myclobutanil, and illustrate the potential selection for individuals with reduced sensitivity (quantitative range) to azoxystrobin by postinfection application and reduced rates of this fungicide 
650 4 |a Journal Article 
700 1 |a Wilcox, Wayne F  |e verfasserin  |4 aut 
773 0 8 |i Enthalten in  |t Plant disease  |d 1997  |g 86(2002), 4 vom: 01. Apr., Seite 394-404  |w (DE-627)NLM098181742  |x 0191-2917  |7 nnns 
773 1 8 |g volume:86  |g year:2002  |g number:4  |g day:01  |g month:04  |g pages:394-404 
856 4 0 |u http://dx.doi.org/10.1094/PDIS.2002.86.4.394  |3 Volltext 
912 |a GBV_USEFLAG_A 
912 |a SYSFLAG_A 
912 |a GBV_NLM 
912 |a GBV_ILN_350 
951 |a AR 
952 |d 86  |j 2002  |e 4  |b 01  |c 04  |h 394-404