What diseases and insect pests does Poinsettia have and how to control them

I. grey mould

1. Symptoms: the disease is harmful to poinsettia. Generally, the catkins are damaged first, so that the catkins appear water stains. The pathogen spread from the catkins to the bracts, causing irregular discoloration spots. After that, the pathogen spread to the branches, causing the branches to produce yellow brown to brown spots. In the later stage, the disease spots obviously sunken down and turned black brown, which in serious cases resulted in the dry of the disease plants.

2. Prevention and control methods: strengthen the maintenance management in winter, increase the indoor temperature and reduce the humidity. If the infected plant is found, it should be moved to the place with ventilation and light immediately, which can play an effective control effect. When the disease is serious, it needs to be treated with Bordeaux spray.

II. Root rot

1. Symptoms: the disease is more serious in high temperature season, which will cause root rot. When you get sick, the roots produce light brown spots. In the later stage, the root could not absorb water seriously because of the disease, leading to the death of the plant due to water shortage.

2. Prevention and control method: strengthen maintenance at ordinary times, and change the plant in time. During maintenance, root can be irrigated with disinfectant every month to inhibit the growth of bacteria. When the disease occurs, the plants can be sprayed with Carbendazim and other chemicals for control.

III. whitefly

1. Symptoms: the main pests of Poinsettia usually occur in large quantities when the temperature is high and the humidity is low. Its adults and larvae will cluster on the back of the leaf and suck the juice of the leaf. Leaves will fade or appear green spots, affecting photosynthesis, leading to poor plant growth. Honeydew discharged by insects often causes mildew.

2. Control method: the Yellow armyworm board can be inserted in the middle of Poinsettia to block the transmission of whitefly. When the disease comes on, you can spray loujingning, chongjike, yifenjing and other drugs to the diseased plant for treatment.