Symptoms: the disease is caused by infection of bacteria, which is manifested as shrinking and deformity of leaves, resulting in dark green spots on the leaves. After infection, the primroses may not bloom, or they may be short and have some stripes, which has a great influence on primroses.
Prevention and control: weeds beside shall be removed to completely reduce the source of infection.
Symptoms: This is also one of the common diseases. After infection, the whole plant turns yellow and starts to dry and die. In humid environment, grey mould spots will appear on the affected parts.
Prevention and control: first of all, we should strengthen prevention, pay attention to the ventilation environment, remove the infected plants in time, and reduce the source of infection. At the beginning of the disease, you can spray 50% sukelin.
Symptoms: the infection is mainly transmitted by strong wind and rain at ordinary times, resulting in brown spots on the leaves of plants.
Prevention and control: at the beginning of the disease, chlorothalonil can be sprayed, which can play an effective role in the treatment of melasma.
Symptoms: it mainly endangers the back position of the leaves, biting the stem and leaves.
Prevention and control: to prevent and control this insect pest, we should start before incubation, scrape off the bark during the winter to destroy it intensively, and smear lime water on the trunk, so that most of the eggs can be killed.
