紫薇白粉病的病原为______，寄主植物为紫薇树。
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桂花叶蜂属______叶蜂科昆虫，只为害桂花。
A. 膜翅目
B. 双翅目
C. 半翅目
D. 脉翅目
对树木进行切刻，纵伤与横伤的深度应该达到______。
A. 表皮层
B. 真皮层
C. 韧皮部
D. 木质部
The thief was arrested after ______.
A. Mrs. Clarke described about him to the police
B. the police found his finger-prints on the wire
C. he went to a doctor about his burned hand
D. a doctor recognized him on the street
下列短截中，可以降低枝位、用于竞争枝处理的是______。
A. 轻短截
B. 中短截
C. 重短截
D. 极重短截
E. 回缩修剪
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