In the early stage of Pelargonium leaf spot, there will be many small water spots on the back of the leaves. As the spots expand and connect, the veins and petioles gradually turn brown, and most of the leaves die. The cuttings are also vulnerable to leaf spot disease. When they are damaged, the branches are difficult to take root, and start to rot from the bottom to the top, and the leaves gradually wither until they die.
Daily maintenance shall be strengthened, ventilation and light transmission shall be conducted frequently to avoid high humidity. Watering should be appropriate, try not to spray water directly on the plant, so as to avoid splashing.
Do not select the plants infected with leaf spot disease or the soil for daily cutting. Most of the pathogens inhabit in the soil will cause the infection of cutting plants.
Remove the diseased plant in time. Those with mild symptoms can be sprayed with Bordeaux solution once every 10-15 days.
Nematode is a common pest of Geranium. When the temperature is between 25 ℃ and 35 ℃, and the humidity is about 40%, it is the most suitable time for nematodes to invade the geranium roots. Nematodes mainly inhabit in the soil, which mainly damage the roots and cause root rot.
Once nematodes appear, it is not easy to eradicate them, and prevention should be carried out in advance. When watering and fertilizing, 3% furan and 10 times water can be used to prevent larva growth effectively.
In addition, nematodes can be found on the surface of the basin soil, covered with a layer of fine sand accompanied with pesticides. Because of the lack of air in the soil, nematodes will soon drill out of the basin soil, and then they can remove the sand and insects together. Two or three times in a row can basically cure the disease.
