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

Fig. 4. Efficacy of azoxystrobin (Quadris) and chlorothalonil (Bravo Weather Stik) spray treatments on Rhabdocline needlecast infection of Douglas-fir at two Pennsylvania sites during 2002. 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 1.29 g a.i./liter, four applications; 1, 2, 3, 4, 5 = Azoxystrobin, 0.14 g a.i./liter, 0.28 g a.i./liter, one application as first or second spray. 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