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Effects of foliar fungicide application on the growing corn plant
The presence of disease and fungus threaten corn health. Foliar fungicide applications to corn (Zea mays) may reduce disease and provide developmental benefits to the crop. The objective of this study was to evaluate the effect of various applications of foliar fungicide on the health and growth of the corn plant.
Eight one-acre plots of corn were planted in 2015. Treatments were replicated once and randomly assigned to one of the plots. Treatments were: CON, no foliar fungicide application; V5, one application of pyraclotrobin (Priaxor; BASF Corp.) foliar fungicide at corn vegetative growth stage V5; R1, one application of pyraclostrobin and metconazole (Headline AMP; BASF Corp.) foliar fungicide at corn reproductive growth stage R1; and V5+R1, one application of pyraclotrobin foliar fungicide at V5 and one application of pyraclostrobin and metconazole foliar fungicide at R1. Total yield for treatments CON, V5, R1, and V5+R1 were 31.6, 33.6, 32.9, and 33.5 tons/acre.
Measurements of height and weight were recorded at two time points: R1 - the silking stage and R3- the kernel milk stage, for six individual corn plants and cobs per row from two locations within each replicate at both time points. The same plant’s leaves, corncobs, and stalks were assessed and collected at R1 and R3. Foliar disease evaluation and scoring of ten random plants within each plot was conducted at R1 and R3. At R3, a 24.7% of disease incidence in plants evaluated showed symptoms of Grey Leaf Spot. Treatment V5 at R3 was most effected by Grey Leaf Spot (15%). Northern Leaf Blight was also found in the field, the highest percentage of disease incidence being in CON (10%) and least disease incidence in V5+R1 (1.63%). Statistical analysis was conducted using the MIXED procedure in SAS. There was no difference (P=0.52) for the weight of the plants among treatments. Applications of foliar fungicide increased (P<0.0001) the average heights for CON, V5, R1, V5+R1 (251±6.9, 297±7.1, 305.28±6.9, 286.46±7.1 cm, respectively). Furthermore, applications of foliar fungicide in V5, R1, V5+R1 (1.44±0.18, 0.83±0.18, 0.88±0.18, respectively) decreased (P=0.0018) the average number of yellow leaves compared with CON (1.71±0.18). In conclusion, applications of foliar fungicides increased plant health, which may contribute to a higher quality feedstuff.
Keywords: corn silage, foliar fungicide, ruminant nutrition