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Effects of corn treated with foliar fungicide at various times of applications on corn silage quality and aerobic stability
About 10 percent of the corn planted in the US is used for corn silage for dairy and beef cattle. Fungicide use on corn has been increasingly investigated within the past few years in order to increase farmers’ yield and profitability. This study utilized four 0.8 ha plots, where each plot was randomly assigned to one of four treatments, as follows; control (CON) corn received no foliar fungicide application; treatment 1 (1X) which corn received one application of pyraclostrobin foliar fungicide (Headline; BASF Corp.) at a rate of 0.11 kg a.i./ha at corn stage V5; treatment 2 (2X) which corn received 2 applications of foliar fungicides, pyraclostrobin at 0.11 kg a.i./ha at corn stage V5, and a mixture of pyraclostrobin + metconazole (Headline AMP; BASF Corp.) at 0.11 + 0.04 kg a.i./ha at corn stage R1; and treatment 3 (3X) which corn received 3 applications of foliar fungicide, pyraclostrobin at 0.11 kg a.i./ha at corn stage V5, pyraclostrobin + metconazole at 0.11 + 0.04 kg a.i./ha at corn stage R1, and pyraclostrobin + metconazole at 0.11 + 0.04 kg a.i./ha at corn stage R3. Foliar disease was evaluated two times during corn silk emergence, and scores for disease severity were assigned to 10 random plants within each plot. Corn was harvested at a dry matter of 33%, 30%, 30%, 32.5% for CON, 1X, 2X, and 3X respectively and then stored in silo bags from September 2013 until April 2014. Corn silage was sampled twice weekly for physical characteristics, major nutrients, net energy, fermentation products, mold count, yeast counts, mycotoxins, denstiy, and aerobic stability. Statistical analysis was performed using the MIXED procedure in SAS. The average temperature for CON, 1X, 2X, and 3X post aeration was different among treatments (32.30, 33.13, 33.68, and 29.10 oC, respectively; P < 0.01). There was a treatment effect (P < 0.05) for content of sugar, fat, ADF, and soluble crude protein. The Neutral detergent fiber content was 47.32 % of DM for CON and 45.28% of DM for 3X (P = 0.05). Total digestible nutrients, as well as net energy of lactation were higher for 3X when compared to CON (P < 0.05). Application of fungicide increased corn silage aerobic stability and energy content, and reduced fiber content which may contribute to a higher quality feedstuff for animals.
Keywords: corn silage, foliar fungicide, aerobic stability