leaf rust of barley

例句：

1. 1.The leaves of the tree are showing signs of leaf rust.
   这棵树的叶子出现了叶锈病的迹象。
2. 2. The rust on the leaves is a sign of poor growing conditions.
   叶子上的锈迹是生长条件不佳的标志。
3. 3. Leaf rust can be spread by insects and can cause significant damage to crops.
   叶锈病可以通过昆虫传播，对农作物造成严重损害。