Control of experimental Phytophthora cinnamomi stem infections of Rhododendron, Leucadendron and Eucalyptus by dimethomorph, fosetyl-Al and metalaxyl
GC Marks and IW Smith
Australian Journal of Experimental Agriculture
30(1) 139 - 143
Published: 1990
Abstract
The efficacy of dimethomorph, (E,Z)-4-[3- (4-chloropheny1)-3-(3,4-dimethoxypheny1)-1 -acryloyl] morpholine, in controlling Phytoplzthora cinnanionii stem infections of Rhododendron, Leucadendron and Eucalyptus was compared with that of fosetyl-Al, metalaxyl and phosphonate (potassium dihydrogen phosphonate) in a phytotron and greenhouse. The plants were inoculated on the stem and the effect of the fungicides applied either as foliar sprays or root drenches on lesion development was measured. The results showed that dimethomorph inhibited lesion extension when applied as a soil drench at rates of 0.6 and 1.2 mg a.i./mL. When used as a soil drench dimethomorph was about as effective as fosetyl-A1 and somewhat less effective than metalaxyl. When applied as foliar sprays, dimethomorph was ineffective and phosphonate was markedly superior to fosetyl-Al. Single applications of the fungicides tested were not able to kill P. cinnanzonzi in established infections within the duration of the experiment and under the test conditions which strongly favoured the fungus. Dimethomorph was slightly phytotoxic to Eucalyptus sieberi at dosages of 1.2 mg a.i./mL.https://doi.org/10.1071/EA9900139
© CSIRO 1990