PREVENTIVE AND CURATIVE CONTROL OF Oidium eucalypti IN Eucalyptus benthamii CLONAL SEEDLINGS

ABSTRACT One of the main diseases occurring in clonal nurseries of Eucalyptus spp. is powdery mildew caused by the fungus Oidium eucalypti. This work evaluated the efficiency of biological products based on Trichoderma spp. and Bacillus spp. applied as preventive and curative treatments for the control of Oidium eucalypti in clonal seedlings of E. benthamii Maiden et Cambage. Treatments were: Trichoderma harzianum (THP), T. atroviride (TAI), T. harzianum (THE), Trichoderma spp. (TTA), Bacillus spp. (BNE), Sulfur (KUM), Difenoconazol (SCO) and distilled water (AD). Treatments were applied preventively by spraying seven days before inoculation of the pathogen, and in curatively, ten days after inoculation. Weekly evaluations of the incidence and severity of the disease were done. The analyzed variables were: Disease Index (ID) and Incidence (I), calculating the area under the disease curve (AUDPC) for each treatment. The results pointed BNE (Bacillus spp.) and TAI (isolate T. atroviride) as effective preventive treatments and BNE (Bacillus spp.), applied curatively for the control of O. eucalypti in E. benthamii seedlings, proving that treatments based on biological products may be effective for controlling eucalyptus powdery mildew in clonal nurseries.

摘要：桉树（Eucalyptus spp.）无性系苗圃的主要病害之一为由桉树粉孢（Oidium eucalypti）引起的白粉病。本研究旨在评估以木霉菌（Trichoderma spp.）和芽孢杆菌（Bacillus spp.）为基础的生物制剂，分别作为预防与治疗手段，对本哈姆桉（E. benthamii Maiden et Cambage）无性系幼苗上的桉树粉孢病害的防控效果。供试处理组包括：哈茨木霉菌（Trichoderma harzianum，THP）、深绿木霉菌（T. atroviride，TAI）、哈茨木霉菌（Trichoderma harzianum，THE）、木霉菌属混合制剂（Trichoderma spp.，TTA）、芽孢杆菌属制剂（Bacillus spp.，BNE）、硫磺（Sulfur，KUM）、苯醚甲环唑（Difenoconazol，SCO）以及蒸馏水（AD）。所有处理均通过喷施方式施药：预防组于病原菌接种前7天施药，治疗组于病原菌接种后10天施药。研究人员每周对病害的发病率与严重度进行调查评估。本研究分析的指标包括病情指数（Disease Index, ID）与发病率（Incidence, I），并计算各处理组的病害曲线下面积（Area Under the Disease Curve, AUDPC）。结果表明，芽孢杆菌属制剂（BNE）与深绿木霉菌菌株（TAI，T. atroviride分离物）可作为有效的预防处理方案；采用治疗施药方式的芽孢杆菌属制剂（BNE），可有效防控本哈姆桉幼苗上的桉树粉孢病害，证实基于生物制剂的处理手段可用于防控桉树无性系苗圃中的桉树白粉病。