The rubber tree (Hevea brasiliensis)–cassava (Manihot esculenta) intercropping system is one of the most popular intercropping patterns for small-holder rubber planters. However, this practice is not recommended in some rubber-producing countries, since it is believed that the rubber tree and cassava share some identical pathogens and that the intercropping system will deplete soil fertility. The effects of cassava allelochemicals on rubber tree pathogens have never been reported. Using controlled plate tests, pot tests, and field experiments, this study aimed to assess the possible adverse effects that cassavas may impart to rubber plantations. The results showed: (1) although the leaf extract, decomposed leaf extract and root exudates of cassava inhibited or had no effect on the mycelial growth of the rubber tree pathogen Corynespora cassiicola, 10 mg mL⁻¹ and 100 mg mL⁻¹ cassava leaf water extracts and testing concentrations of cassava root extraction significantly promoted the mycelial growth of the rubber tree pathogen Rigidoporus lignosus, which increased the risk of rubber tree white root disease; (2) the overall soil fertility was increased significantly in the rubber tree–cassava intercropping system. However, the soil phosphorus content was reduced significantly in the field experiment; (3) the average girth of rubber trees was significantly reduced, and the girth uniformity was decreased in the intercropping system. Based on the experiment results, we suggested that an optimised fertiliser recommendation, particularly on the phosphorus amount, should be developed and implemented for the rubber tree–cassava intercropping system. In addition, since the intercropping of cassava will increase the risk of R. lignosus-induced rubber tree white root disease, which is very hard to prevent and eradicate once rubber trees are infected, the intercropping of cassava in rubber plantation rows should not be recommended in the R. lignosus prevailing areas.

橡胶树（巴西橡胶树）-木薯（Manihot esculenta）套作系统是小农橡胶播种机最流行的套作模式之一。但是，在某些橡胶生产国不建议采用这种做法，因为据信橡胶树和木薯具有相同的病原体，并且间作系统会耗尽土壤的肥力。从未报道过木薯化感物质对橡胶树病原体的影响。本研究使用受控平板试验，盆栽试验和田间试验，旨在评估木薯可能给橡胶园带来的不利影响。结果表明：（1）尽管木薯的叶提取物，腐烂的叶提取物和根系分泌物抑制或不影响橡胶树病原体Corynespora cassiicola的菌丝体生长，但10 mg mL ^-1和100 mg mL ^-1的木薯叶水提取物，并检测木薯根提取物的浓度可显着促进橡胶树病原体木质假单胞菌的菌丝体生长，增加了橡胶树白根病的风险；（2）橡胶树-木薯间作系统的整体土壤肥力显着提高。然而，在田间试验中，土壤磷含量显着降低。（3）间作系统中橡胶树的平均周长明显减少，周长均匀性降低。根据实验结果，我们建议应针对橡胶树-木薯间作系统开发并实施优化的肥料推荐，尤其是磷含量。此外，由于木薯间作会增加木糖罗非鱼的风险引起的橡胶树白根病，一旦橡胶树被感染，很难预防和根除，因此不应在木犀草流行地区建议在橡胶种植园行间种植木薯。