Berg, L. L.1; Lubenow, L.2; Endres, G.3; Bjerke, K.4
1Towner County Extension Agent, ANR, North Dakota State University, Cando, ND, 58324
2Extension Specialist, North Dakota State University, Langdon, ND, 58249
3Extension Specialist, North Dakota State University, Carrington, ND, 58421
4Research Technician, North Dakota State University, Carrington, ND, 58421


The objective of this greenhouse study is to determine soybean plant response to Priaxor® (fluxapyroxad + pyraclostrobin) application after simulated hail injury (33% defoliation, 66% defoliation, stem bent at 135-degree angle, and stem cut-off) at the R2 and R5 soybean growth stages.  Priaxor® was applied at 4 fl oz/a three days post plant injury. Plant greenness was observed and measured using the Minolta SPAD-502 chlorophyll meter.  Plant maturity date was noted at the R8 growth stage. Seed was hand-harvested and seed weight was determined. No interactions between fungicide and hail injury level were recorded. Foliar fungicide application did not increase seed yield nor change plant maturity date when averaged across R2 and R5. Hail injury impacted plant maturity and seed weight across crop stages.  The 33% defoliation injury level was similar in plant maturity and seed weight compared to untreated. More severe defoliation methods reduced seed yield by 19 to 32% and plant maturity was delayed 5 to 11 days as compared to the control. At R2, the plants were greener nine days post fungicide application than nontreated plants, however this was temporary. Greenness observations after this timing were not significantly different.

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