Abstract Rice blast (Pyricularia oryzae Cavara) is one of the most devastating diseases affecting the rice crop in Cambodia and other countries in the world. The fungus Trichoderma spp. is known as one of biological control agents applied as a soil treatment, seed treatment and foliar application, that is used for suppression of various diseases caused by fungal pathogens. Trichoderma harzianum strain BTB 022 is one of the commercial biological control products available in Cambodian markets. The combined use of T. harzianum and a resistant variety, to manage blast disease, are considered as sustainable approaches to reduce yield losses and to cope with recent restrictions on fungicide use. A series of consecutive experiments was conducted to examine the effectiveness of T. harzianum on suppression of rice blast incidence in Koktrap and Polors agricultural research stations during wet and dry seasons in 2016 and 2017. In both years, the treatments consisted of the use of Trichoderma on susceptible and resistant rice varieties. In 2017 the two treatments were combined with conventional practice treatments representing the average farmers' practice. The experiments were arranged in randomized complete block design with three replications in 2016 and four replications in 2017. Leaf blast incidence was assessed at five and four growth stages in 2016 and 2017, respectively, and the area under the leaf blast progress curve (AULBPC) was computed for each year and location. Neck blast (NB) incidence was assessed at dough stage and grain yield (GY) was measured at ripening stage. T. harzianum reduced the incidence of leaf blast and neck blast on IR504 (susceptible strain), but its efficacy was not consistent. The magnitude of disease suppression by T. harzianum was higher for neck blast than for leaf blast. GY variation was correlated with AULBPC and NB incidence, which suggests that disease reduction corresponded to an increase in yield (AULBPC: r = −0.877, P

中文翻译：

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使用哈茨木霉及其抗性品种在柬埔寨稻田中进行稻瘟病管理

摘要 稻瘟病（Pyricularia oryzae Cavara）是影响柬埔寨和世界其他国家水稻作物的最具破坏性的病害之一。真菌木霉属。已知作为土壤处理、种子处理和叶面施用的生物防治剂之一，用于抑制由真菌病原体引起的各种疾病。哈茨木霉菌株 BTB 022 是柬埔寨市场上可用的商业生物防治产品之一。联合使用哈茨木霉和抗性品种来控制稻瘟病，被认为是减少产量损失和应对近期杀菌剂使用限制的可持续方法。进行了一系列连续实验以检查 T 的有效性。harzianum 在 2016 年和 2017 年湿季和旱季期间 Koktrap 和 Polors 农业研究站抑制稻瘟病发病率的作用。 在这两年中，处理包括对易感和抗性水稻品种使用木霉。2017 年，这两种处理方式与代表普通农民实践的常规实践处理相结合。实验采用随机完整区组设计，2016 年重复 3 次，2017 年重复 4 次。 分别在 2016 年和 2017 年评估了 5 个和 4 个生长阶段的叶瘟发生率，以及叶瘟进展曲线下面积 (AULBPC)每年和地点计算。在面团阶段评估颈裂 (NB) 发生率，在成熟阶段测量谷物产量 (GY)。T。harzianum 降低了 IR504（敏感菌株）的叶瘟和颈瘟的发生率，但其功效并不一致。T. harzianum 对颈瘟的病害抑制程度高于叶瘟。GY 变异与 AULBPC 和 NB 发生率相关，这表明疾病减少对应于产量的增加（AULBPC：r = -0.877，P