Evaluation of foliar fungicides on corn in 2011
Stalk rot severity was low (approximately 1 on the University of Illinois 1 to 5 scale) at all five locations where it was assessed. Treatment differences were detected only at the Armstrong location; stalk rot severity was significantly lower with applications of fungicide made at V5+R1 (0.0 to 0.35 versus 0.8 for the unsprayed check).
Seed moisture ranged from 14.4 to 20.5 percent depending on the location, but did not differ more than a few tenths of a percent amongst treatments within any location.
Yield varied across locations ranging from 156.7 to 229.6 bu/ac in the untreated control (Table 1). No differences in yield were detected between fungicide treatments and the untreated control at five of the six locations. At Armstrong, lower yields (P=0.08) occurred with some treatments than the unsprayed check.
Where foliar disease severity was moderate to high, all fungicide products successfully reduced disease when applied during early reproductive growth stages. Applications of fungicides made at V5 to V6 had no effect on foliar disease severity. Surprisingly low stalk rot disease occurred in the trial at all locations. There were no significant positive yield responses to fungicide applications. There was no justification in terms of reduced disease severity or yield response for double applications of fungicides made at V5 and R1.