Through partitioning of ecological niches, several fungi are able to coexist on the same host crop. In (partial) absence of niche partitioning, competitive exclusion among fungi can occur. Competitive exclusion is one of the bases for biocontrol. We investigated fungal correlations, in terms of relative abundance of the fungi, in pre-harvest maize, as a natural ecosystem model. Internal mycobiome fungal relative abundance of maize was used to establish correlations. The maize had been harvested from dry and wet agro-ecological zones of Zambia. The relative abundances of the fungal genera were determined using DNA amplicon sequencing. For this study, positive or absence of correlations between fungal genera signified good niche partitioning (co-existence), whereas negative correlations signified poor niche partitioning and potential for competitive exclusion. When species compete within one niche (competitive exclusion), we may expect to detect higher levels of mycotoxins—since mycotoxins are considered antagonistic agents aimed at defending or invading an ecological niche. To estimate the importance of mycotoxins in competitive exclusion, we measured the influence of the fungal correlations on levels of fumonisin-B1 (FB1) in the maize. FB1 data were derived from a previous study on the maize, determined by HPLC. Results showed that Sarocladium and Stenocarpella had the strongest significant negative correlation with Fusarium, suggesting poor niche partitioning and potential for antagonism of these genera with Fusarium. Furthermore, higher levels of Stenocarpella resonated with lower levels of FB1 and vice versa. It was also observed that, when Sarocladium was in low abundance (< 10%), the frequency of detection of higher levels of FB1 (> 100 µg kg⁻¹) in the pre-harvest maize was highest.

通过生态位的划分，多种真菌能够在同一寄主作物上共存。在（部分）缺乏生态位划分的情况下，真菌之间可能会发生竞争排斥。竞争排斥是生物防治的基础之一。我们根据收获前玉米中真菌的相对丰度来研究真菌相关性，作为自然生态系统模型。使用玉米的内部分枝菌组真菌相对丰度来建立相关性。这些玉米是从赞比亚的干燥和湿润农业生态区收获的。使用 DNA 扩增子测序确定真菌属的相对丰度。在这项研究中，真菌属之间的正相关或不相关意味着良好的生态位划分（共存），而负相关则意味着较差的生态位划分和潜在的竞争排斥。当物种在一个生态位内竞争（竞争排斥）时，我们可能会检测到更高水平的霉菌毒素，因为霉菌毒素被认为是旨在防御或入侵生态位的拮抗剂。为了评估霉菌毒素在竞争排斥中的重要性，我们测量了真菌相关性对玉米中伏马菌素 B1 (FB1) 水平的影响。 FB1 数据源自之前对玉米的研究，通过 HPLC 测定。结果表明，Sarocladium和Stenocarpella与Fusarium的显着负相关性最强，表明这些属的生态位划分较差，且具有与Fusarium拮抗的潜力。此外，较高水平的Stenocarpella与较低水平的 FB1 产生共振，反之亦然。还观察到，当Sarocladium丰度较低（< 10%）时，收获前玉米中检测到较高水平 FB1（> 100 µg kg ^{-1 ）的频率最高。}