Common diseases and pests of African violets and their control

Common diseases of African violets and their prevention and treatment

Root-knot nematode disease

This is a root disease caused by root-knot nematodes. The symptoms are the formation of nodular root nodes of varying sizes on the fibrous roots and lateral roots. The color of the root nodes is milky white at first, and then turns light brown. When the root nodes are cut open, tiny milky white nematodes will be found inside. The disease will cause the plant to be short and poorly developed. Specific prevention and control methods are as follows:

You can use 5% chlorpyrifos, the dosage of which is generally 0.1% of the soil weight; or you can use 10% propamidophos, the dosage of which can be referred to the size of the flower pot, such as 0.5 grams is generally applied to a 6 cm flower pot. Both agents can be used during the growth period of African violets, but the best effect is achieved before planting.

Sclerotium rolfsii

The disease mainly harms the stem base and roots of African violets. Initially, some water-soaked yellow-brown spots will appear at the base of the plant close to the soil, which will quickly expand and invade the roots. In severe cases, the affected areas will rot and the entire plant will die. To prevent and control white rot, fungicides such as carbendazim, Bordeaux mixture, and Baume lime sulfur can be sprayed on the base of the plant stems and the substrate.

Leaf spot

The disease mainly damages the lower leaves of African violets. In the early stages of leaf spot disease, small necrotic spots will appear on the leaves, and then the spots will expand rapidly, and the diameter of the spots may reach more than 5 cm. Specific prevention and control methods are as follows:

In the early stage of the disease, generally spray fungicides such as carbendazim, thiophanate-methyl, thiophanate-methyl, and benomyl for prevention and control every 7-10 days, and spray 2-3 times in a row.

Disease

The disease first manifests itself on the leaves, with water-soaked brown spots and obvious ring patterns. Under humid conditions, the lesions expand rapidly, with unclear edges, and sparse white mold will appear. Under dry conditions, the lesions stop expanding and the diseased tissue dries up. For the prevention and control of the disease, you can spray metalaxyl, ethylene phosphine aluminum, chlorpyrifos and alum and other agents for prevention and control.

Common Pests of African Violaceae and Their Control

The main pests of African violets are scale insects and red spiders, which often occur during the growth period of the plant. You can spray 40% omethoate emulsifiable concentrate 1000 to prevent and control the pests.