EFFECTS OF PRODIAMINE ON TALL FESCUE (FESTUCA-ARUNDINACEA) ROOTING

With the increased development of new tall fescue cultivars used in tu rf, it is important to understand their individual response to herbici de treatment. The effect of prodiamine on tall fescue root dry weight and root length of selected tall fescue cultivars was studied in the g reenhouse in 1.3-m-deep pots of calcined clay. Prodiamine at 0.8 kg ai /ha did not significantly affect either root dry weight or root length . However, the mean root dry weight and maximum root length averaged o ver all cultivars were significantly reduced at 4 wk after treatment w ith 1.7 kg/ha. When the prodiamine treatments were repeated in a secon d experiment, both rates caused a significant reduction in the mean ro ot dry weight and maximum root length but there was no significant dif ference between prodiamine rates. Single degree of freedom contrasts b etween the untreated and treated turfs for each cultivar had some diff erential response in root dry weight. The reduction in root dry weight in the prodiamine treatments was more pronounced in the second study because the turf was less mature. 'Olympic' and 'Rebel' tall fescue ha d significantly reduced root dry weight at the 1.7 kg/ha rate in first study; whereas,'Amigo,' Olympic, 'Sundance,' and 'Taurus' tall fescue had significant reduction in root dry weight at both 0.8 and 1.7 kg/h a prodiamine rates. 'Midnight' Kentucky bluegrass had significantly re duced root length at both prodiamine rates in the second experiment bu t in general there was little difference among tall fescue cultivars t reated with prodiamine.