我家的也是这样, 每次都剪掉长斑的叶子和发黑的树枝,可是马上又长出来了, 怎么办
我的玫瑰没有得过黑斑,没有试验过。有人说有大蒜液可以治,你可以试试。
帮你查了Sheridan Nursery的玫瑰种植,关于病虫害的防治如下:
Pest Control
Roses, like all plants, can have insect problems.
- Watch for aphids which are small, soft-bodied insects that can be bright green, brown, red, or black. They usually cluster around the new growing shoots or on young flower buds.
- Spider mites are tiny and suck sap from the underside of leaves. Look for flecked foliage that turns yellow and drops off. Insecticidal soap is the easiest, most environmentally friendly solution to these problems.
- Black Spot looks exactly like its name while Powdery Mildew is a white, powder-like covering of the leaves and stems. Try to grow roses that are labeled “disease-resistant” to minimize the occurrence of these 2 conditions. If this happens, it has to be treated or your rose bush will defoliate and be weakened in the process.
- Sulphur Dust, Lime Sulphur and Safer’s Defender are three excellent organic fungicides. Start using one in early July, before you see any signs of disease, and continue every 2 weeks until late September. Safer’s End-All is an organic insecticide that can be used to control most insect pests. Dormant Spray can also be applied in March/Early April.
要想治疗效果快,去Sheridan Nursery问问,买哪种Spay治黑斑。我觉得你应该注意土壤的消毒,通常这种病菌是通过土壤传播的,光摘掉病叶还不够。盆栽的话就换新土,地栽土壤要消毒,休眠期再喷石硫合剂吧。