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This study was conducted to evaluate the effect of lactic acid bacteria (LAB) on fermentation quality, mycotoxin concentrations, and microbial communities of whole-crop corn silages infested with mycotoxigenic fungi. Cultured spores (10⁶ cfu/mL) of mycotoxigenic <i>Aspergillus flavus</i> and <i>Fusarium graminearum</i> were sprayed (5 mL) on corn forage on 27 July and 10 August 2018. On 21 August 2018, sprayed (FI; 3 plots) and unsprayed (NFI; 3 plots) corn forage were harvested at the 1/2 kernel milk line stage, followed by chopping and ensiling without inoculants (CON), or with <i>Lactobacillus buchneri</i> (LB, 1 × 10⁶ cfu/g FW), <i>Lactobacillus plantarum</i> (LT, 1 × 10⁶ cfu/g FW), or <i>L. buchneri</i> + <i>L. plantarum</i> (BT: both <i>L. buchneri</i> and <i>L. plantarum</i> applied at 0.5 × 10⁶ cfu/g FW). After 90 d of ensiling, FI silages had a higher (<i>p</i> < 0.05) pH value and higher acetic acid (ACA), ethanol, and ammonia nitrogen (ammonia N) concentrations, but lower (<i>p</i> < 0.05) lactic acid (LA) concentrations than NFI silage. The inoculants decreased pH and increased LA concentration and LA/ACA compared with CON. The aflatoxin B₁ (AFB₁) was only detected in FI fresh corn and silages; ensiling decreased (<i>p</i> < 0.05) AFB₁ concentration compared with fresh corn, and LB and BT decreased AFB₁ concentration compared with CON. The zearalenone (ZEN), deoxynivalenol (DON), and fumonisin B₁ (FB₁) concentrations were similar (<i>p</i> < 0.05) for NFI silages, while ZEN concentration in BT was the lowest (<i>p</i> < 0.05) among all FI silages; DON and FB₁ concentrations in LB, LT, and BT silages were significantly lower (<i>p</i> < 0.05) than those of CON in FI silages. The fungal infestation increased the bacterial and fungal diversity of silages compared with NFI silages. The FI silages had a higher relative abundance (RA) of <i>Lactobacillus</i>, <i>Weissella</i>, <i>Wickerhamomyces</i>, <i>Pichia</i>, and <i>Epicoccum</i> than the corresponding NFI silages. The RA of <i>Aspergillus</i> and <i>Fusarium</i> markedly decreased after 90 d of ensiling, and the inoculation expanded this trend irrespective of fungal infestation. The <i>Penicillium</i> in FI silages survived after 90 d of ensiling, while the inoculants decreased the RA of <i>Penicillium</i>. Inoculants mitigate the adverse effects of fungal infestation on corn silage quality by changing the bacterial and fungal communities.