Common diseases of geranium and their control

The main diseases of geranium are:

① leaf spot disease. Early leaves will appear needle-sized, round or irregular brown spots, and then gradually expand into dark brown or auburn spots, serious when the whole leaf is full of disease spots, until dry and fall off; its stem and branches are also black, wrinkled and rotten, even the leaves on the stem wither and die, leaving only a few leaves at the top. Preventive measures: a. The density should not be too high during greenhouse cultivation, and attention should be paid to frequent ventilation and light transmission;b. Avoid watering the plants and avoiding water droplets splashing;c. Avoid cutting cuttings on diseased plants, and if diseased leaves and diseased branches are found, cut them off and burn them in time;d. Spray 200-fold equivalent Bordeaux mixture once every 2 weeks during high humidity period for 3 consecutive times.

② Grey mold. The disease is mainly caused by excessive watering, if encountered cold and wet when the incidence of more central. First harm flowers, so that the edge of the petals dark withered, air humidity will appear gray mold layer, floret kink together, the victim petals fall on the leaves, but also cause the disease of the leaves. Brown spots like water stains appear on the leaves, and after drying, they are covered with light gray layers. Prevention and control measures: a. timely removal of diseased leaves and flowers, watering to avoid feeling the plant, timely removal of water leaves and flowers, often pay attention to ventilation and light transmission;b. early stage of disease timely use 75% chlorothalonil 500 times solution spray, 3 consecutive times.