Molecular Pathogens, 2025, Vol.16, No.3, 100-110 http://microbescipublisher.com/index.php/mp 105 continuous cropping plots, and the crop growth cycle was extended and the grains were full (Jalli et al., 2021). Analysis shows that flavonoids secreted by the rhizosphere of legumes have a significant inhibitory effect on Fusarium, while increasing the proportion of Bacillus bacteria in the root zone. These strains have both antagonistic and inducing functions (Torres-Rodríguez et al., 2022). For the root rot caused by Macrophomina phaseolina, its dormant structure - microsclerotia - can survive in the soil for more than 5 years, so short-term rotation is difficult to significantly reduce the amount of pathogens (Little et al., 2023). However, long-term rotation with non-host crops such as cotton, sesame or high-oleic peanuts can reduce its nutrient source and enhance the ability of soil microorganisms to decompose microsclerotia. In field trials in India, after three years of sorghum-peanut-sesame rotation, the incidence of root rot decreased by more than 40%, and the rate of lesion expansion was significantly slowed down (Li et al., 2024). 5 Effects of Sorghum Rotation on Pest Populations 5.1 Dynamic changes in pest populations and host avoidance In sorghum planting systems, underground pests (such as white grubs and wireworms), aboveground sucking pests (such as aphids) and chewing pests (such as armyworms and ear borers) cause damage to crops at different stages, and their occurrence is highly host-dependent. Studies have shown that crop rotation can effectively disrupt the generational continuity and host-locating behavior of these pests and reduce insect population density in the field (Okosun et al., 2021). Crop rotation creates an environment that is not conducive to the survival and reproduction of specific pests by replacing crop species, thereby causing pests to decline naturally in the absence of hosts (Khan et al., 2016). Taking the sugarcane aphid (Melanaphis sacchari) as an example, this pest has a strong specialization for sorghum, and rotating soybeans or cotton for one year can significantly reduce the size of its overwintering population. Experiments have shown that under the sorghum-soybean rotation model, the insect population density of sugarcane aphids in spring was reduced by 46.3% compared with the continuous cropping area, and the degree of field damage was significantly reduced (Sun et al., 2024). Noctuid pests such as armyworms (Mythimna separata) have the habit of phototropism and feeding on grass leaves, and continuous sorghum fields often form a stable feeding and oviposition base for them. After one year of rotation with non-host crops such as legumes and crucifers, the number of adults decreased, and the hatching rate and survival rate of larvae were significantly limited (Okosun et al., 2021). In a field survey in Iowa, the number of corn borers in the continuous sorghum planting area was nearly twice that of the rotation area, indicating that rotation has a significant population suppression effect (Schlegel et al., 2017).Therefore, the rotation system breaks the dependence between pests and hosts through the "ecological dislocation" intervention mechanism, effectively inhibiting the expansion trend of major pest populations. 5.2 Dual Regulation of Soil and Ground Pests By Crop Rotation 5.2.1 Control of underground pest population Underground pests mainly feed on sorghum rhizomes during the seedling stage. In severe cases, it can lead to seedling loss and ridge breakage, slow plant growth, and seriously affect yield. The survival of such pests depends on continuous and suitable root structure and underground organic matter sources. The rotation system can break their habitat by replacing non-host crops, thereby weakening the population base. In the sorghum-alfalfa rotation system, studies have found that certain phenolic compounds in alfalfa root secretions have a repellent effect on underground pest larvae, and the number of wireworms decreased by about 37% after one year of rotation . In addition, crop rotation promotes the recovery of natural enemy groups such as predatory nematodes, ground beetles and ground-dwelling spiders, providing a natural biological control barrier for underground pests (Carrión et al., 2019). Crop rotation can also break the "soil memory effect" of underground pests. Some pests can overwinter in the rhizosphere of sorghum using the residues of the previous crop. Crop rotation removes sorghum stalks and adjusts
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