02484nam a2200265 a 450000100080000000500110000800800410001910000190006024500480007926000580012730000090018550000180019452018560021265000150206865000140208365000160209765000090211365300080212265300150213065300110214565300210215665300210217765300120219865300080221014443842009-06-01       1977    bl uuuu  m   00u1 u    #d1 aHENNING, A. A.  aEvaluation of foliar fungicides on soybean.  aMississippi State: Mississippi State Universityc1977  a68p.  aM.Sc. Thesis.  aSoybean diseases frequently cause yield reductions and low quality seed. Recently, foliar application of fungicides has been reported to increase yield and improve seed quality in soybean. In this study, the effect of four foliar fungicides on leaf disease severity and leaf retention, yield components, yield, and seed infection, as well as the effect os spray timing and number of benomyl applications on the seed quality of Forrest soybean were investigated. Distinct differences were observed in the incidence of leaf diseases and leaf retention. Sprayed plants remained green longer than the controls. Yield increases were observed but they were not significant at the 5% level of probability. The effect of the fungicides on the yield components studied did not explain the observed yield increases; olny the 250-seed weight was significantly increased in some causes. The number of seed per pod and pods per plant were not increased by the treatments. Diaporthe phaseolorum was the most frequent fungus isolated from surface-sterilized seed. All fungicides reduced the incidence of seedborne fungi, but not statistically significant results were found. The overall results of this work showed that benomyl was, in all cases, the most effective fungicide, followed by chlorothalonil, thiabendazole, and pyrithione in order. In regard to seed quality, no advantage was found in adding a third fungicide application nor in delaying the normal spray schedule; although, the percentage of infected seed was reduced in both cases. Two fungicide applications (normal treatment) resulted in higher germination and vigor; however, only the vigor was significantly increased by the treatments. The 25-seed weight and the leaf retention were significantly increased over the control and other treatments when a third spray was adde to the normal schedule.  afungicides  aFungicida  aGlycine Max  aSoja  aEUA  aEvaluation  aFoliar  aFoliar fungicide  aFungicida foliar  aSoybean  aUSA