Effects of Azoxystrobin Application Rate and Treatment Interval on the Control of <i>Rhabdocline</i> <i>pseudotsugae</i> on Douglas-fir Christmas Trees

Fig. 5. Efficacy of azoxystrobin (Quadris) and chlorothalonil (Bravo Weather Stik) spray treatments on Rhabdocline needlecast infection of Douglas-fir at two Pennsylvania sites during 2003. Disease Index = disease severity (1 to 5 scale; 1 = no infection) x disease incidence (needles with one or more lesions). Control = untreated trees; Standard = chlorothalonil 1.7 kg a.i/ha, four applications; 1, 2, 3 = azoxystrobin, 0.28 g a.i./liter, 0.55 g a.i./liter, 1.10 g a.i./liter, four applications. Letters indicate significant differences between treatments. Mean separation was tested according to Fisher’s protected Least Significance test (LSD; P = 0.05).



Image from Plant Health Progress article:
Effects of Azoxystrobin Application Rate and Treatment Interval on the Control of Rhabdocline pseudotsugae on Douglas-fir Christmas Trees