落叶松幼苗心止病,也称早期封顶病。在苗木出土后,刚进入生长初期,长出五六轮真叶,苗高4～8厘米左右时,突然停止了高生长,在幼苗顶端长出圆圆的小芽苞,起初呈绿色,经三四天变为褐色,完成了年生长发育。落叶松幼苗心止病是一种生态病害,防治方法如下:1.正确选择育苗地。要选择沙 Larch seedling heart disease, also known as early cap disease. In the unearthed nursery stock, just entered the early stages of growth, grow five or six round true leaves, height 4 to 8 cm or so, suddenly stopped high growth, the top of the seedlings grow round bud buds, initially green, the Three or four days into a brown, completed the annual growth and development. Larch seedling heart disease is an ecological disease, prevention and treatment as follows: 1. Proper selection of nursery. To choose sand